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Java example source code file (CachedRowSet.java)
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The CachedRowSet.java Java example source code
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package javax.sql.rowset;
import java.sql.*;
import javax.sql.*;
import javax.naming.*;
import java.io.*;
import java.math.*;
import java.util.*;
import javax.sql.rowset.spi.*;
/**
* The interface that all standard implementations of
* <code>CachedRowSet must implement.
* <P>
* The reference implementation of the <code>CachedRowSet interface provided
* by Oracle Corporation is a standard implementation. Developers may use this implementation
* just as it is, they may extend it, or they may choose to write their own implementations
* of this interface.
* <P>
* A <code>CachedRowSet object is a container for rows of data
* that caches its rows in memory, which makes it possible to operate without always being
* connected to its data source. Further, it is a
* JavaBeans™ component and is scrollable,
* updatable, and serializable. A <code>CachedRowSet object typically
* contains rows from a result set, but it can also contain rows from any file
* with a tabular format, such as a spread sheet. The reference implementation
* supports getting data only from a <code>ResultSet object, but
* developers can extend the <code>SyncProvider implementations to provide
* access to other tabular data sources.
* <P>
* An application can modify the data in a <code>CachedRowSet object, and
* those modifications can then be propagated back to the source of the data.
* <P>
* A <code>CachedRowSet object is a disconnected rowset, which means
* that it makes use of a connection to its data source only briefly. It connects to its
* data source while it is reading data to populate itself with rows and again
* while it is propagating changes back to its underlying data source. The rest
* of the time, a <code>CachedRowSet object is disconnected, including
* while its data is being modified. Being disconnected makes a <code>RowSet
* object much leaner and therefore much easier to pass to another component. For
* example, a disconnected <code>RowSet object can be serialized and passed
* over the wire to a thin client such as a personal digital assistant (PDA).
*
*
* <h3>1.0 Creating a CachedRowSet Object
* The following line of code uses the default constructor for
* <code>CachedRowSet
* supplied in the reference implementation (RI) to create a default
* <code>CachedRowSet object.
* <PRE>
* CachedRowSetImpl crs = new CachedRowSetImpl();
* </PRE>
* This new <code>CachedRowSet object will have its properties set to the
* default properties of a <code>BaseRowSet object, and, in addition, it will
* have an <code>RIOptimisticProvider object as its synchronization provider.
* <code>RIOptimisticProvider, one of two SyncProvider
* implementations included in the RI, is the default provider that the
* <code>SyncFactory singleton will supply when no synchronization
* provider is specified.
* <P>
* A <code>SyncProvider object provides a CachedRowSet object
* with a reader (a <code>RowSetReader object) for reading data from a
* data source to populate itself with data. A reader can be implemented to read
* data from a <code>ResultSet object or from a file with a tabular format.
* A <code>SyncProvider object also provides
* a writer (a <code>RowSetWriter object) for synchronizing any
* modifications to the <code>CachedRowSet object's data made while it was
* disconnected with the data in the underlying data source.
* <P>
* A writer can be implemented to exercise various degrees of care in checking
* for conflicts and in avoiding them.
* (A conflict occurs when a value in the data source has been changed after
* the rowset populated itself with that value.)
* The <code>RIOptimisticProvider implementation assumes there will be
* few or no conflicts and therefore sets no locks. It updates the data source
* with values from the <code>CachedRowSet object only if there are no
* conflicts.
* Other writers can be implemented so that they always write modified data to
* the data source, which can be accomplished either by not checking for conflicts
* or, on the other end of the spectrum, by setting locks sufficient to prevent data
* in the data source from being changed. Still other writer implementations can be
* somewhere in between.
* <P>
* A <code>CachedRowSet object may use any
* <code>SyncProvider implementation that has been registered
* with the <code>SyncFactory singleton. An application
* can find out which <code>SyncProvider implementations have been
* registered by calling the following line of code.
* <PRE>
* java.util.Enumeration providers = SyncFactory.getRegisteredProviders();
* </PRE>
* <P>
* There are two ways for a <code>CachedRowSet object to specify which
* <code>SyncProvider object it will use.
* <UL>
* <LI>Supplying the name of the implementation to the constructor
* The following line of code creates the <code>CachedRowSet
* object <i>crs2 that is initialized with default values except that its
* <code>SyncProvider object is the one specified.
* <PRE>
* CachedRowSetImpl crs2 = new CachedRowSetImpl(
* "com.fred.providers.HighAvailabilityProvider");
* </PRE>
* <LI>Setting the SyncProvider using the CachedRowSet
* method <code>setSyncProvider
* The following line of code resets the <code>SyncProvider object
* for <i>crs, the CachedRowSet object created with the
* default constructor.
* <PRE>
* crs.setSyncProvider("com.fred.providers.HighAvailabilityProvider");
* </PRE>
* </UL>
* See the comments for <code>SyncFactory and SyncProvider for
* more details.
*
*
* <h3>2.0 Retrieving Data from a CachedRowSet Object
* Data is retrieved from a <code>CachedRowSet object by using the
* getter methods inherited from the <code>ResultSet
* interface. The following examples, in which <code>crs is a
* <code>CachedRowSet
* object, demonstrate how to iterate through the rows, retrieving the column
* values in each row. The first example uses the version of the
* getter methods that take a column number; the second example
* uses the version that takes a column name. Column numbers are generally
* used when the <code>RowSet object's command
* is of the form <code>SELECT * FROM TABLENAME; column names are most
* commonly used when the command specifies columns by name.
* <PRE>
* while (crs.next()) {
* String name = crs.getString(1);
* int id = crs.getInt(2);
* Clob comment = crs.getClob(3);
* short dept = crs.getShort(4);
* System.out.println(name + " " + id + " " + comment + " " + dept);
* }
* </PRE>
*
* <PRE>
* while (crs.next()) {
* String name = crs.getString("NAME");
* int id = crs.getInt("ID");
* Clob comment = crs.getClob("COM");
* short dept = crs.getShort("DEPT");
* System.out.println(name + " " + id + " " + comment + " " + dept);
* }
* </PRE>
* <h4>2.1 Retrieving RowSetMetaData
* An application can get information about the columns in a <code>CachedRowSet
* object by calling <code>ResultSetMetaData and RowSetMetaData
* methods on a <code>RowSetMetaData object. The following code fragment,
* in which <i>crs is a CachedRowSet object, illustrates the process.
* The first line creates a <code>RowSetMetaData object with information
* about the columns in <i>crs. The method getMetaData,
* inherited from the <code>ResultSet interface, returns a
* <code>ResultSetMetaData object, which is cast to a
* <code>RowSetMetaData object before being assigned to the variable
* <i>rsmd. The second line finds out how many columns jrs has, and
* the third line gets the JDBC type of values stored in the second column of
* <code>jrs.
* <PRE>
* RowSetMetaData rsmd = (RowSetMetaData)crs.getMetaData();
* int count = rsmd.getColumnCount();
* int type = rsmd.getColumnType(2);
* </PRE>
* The <code>RowSetMetaData interface differs from the
* <code>ResultSetMetaData interface in two ways.
* <UL>
* <LI>It includes setter methods: A RowSet
* object uses these methods internally when it is populated with data from a
* different <code>ResultSet object.
*
* <LI>It contains fewer getter methods: Some
* <code>ResultSetMetaData methods to not apply to a RowSet
* object. For example, methods retrieving whether a column value is writable
* or read only do not apply because all of a <code>RowSet object's
* columns will be writable or read only, depending on whether the rowset is
* updatable or not.
* </UL>
* NOTE: In order to return a <code>RowSetMetaData object, implementations must
* override the <code>getMetaData() method defined in
* <code>java.sql.ResultSet and return a RowSetMetaData object.
*
* <h3>3.0 Updating a CachedRowSet Object
* Updating a <code>CachedRowSet object is similar to updating a
* <code>ResultSet object, but because the rowset is not connected to
* its data source while it is being updated, it must take an additional step
* to effect changes in its underlying data source. After calling the method
* <code>updateRow or insertRow, a
* <code>CachedRowSet
* object must also call the method <code>acceptChanges to have updates
* written to the data source. The following example, in which the cursor is
* on a row in the <code>CachedRowSet object crs, shows
* the code required to update two column values in the current row and also
* update the <code>RowSet object's underlying data source.
* <PRE>
* crs.updateShort(3, 58);
* crs.updateInt(4, 150000);
* crs.updateRow();
* crs.acceptChanges();
* </PRE>
* <P>
* The next example demonstrates moving to the insert row, building a new
* row on the insert row, inserting it into the rowset, and then calling the
* method <code>acceptChanges to add the new row to the underlying data
* source. Note that as with the getter methods, the updater methods may take
* either a column index or a column name to designate the column being acted upon.
* <PRE>
* crs.moveToInsertRow();
* crs.updateString("Name", "Shakespeare");
* crs.updateInt("ID", 10098347);
* crs.updateShort("Age", 58);
* crs.updateInt("Sal", 150000);
* crs.insertRow();
* crs.moveToCurrentRow();
* crs.acceptChanges();
* </PRE>
* <P>
* NOTE: Where the <code>insertRow() method inserts the contents of a
* <code>CachedRowSet object's insert row is implementation-defined.
* The reference implementation for the <code>CachedRowSet interface
* inserts a new row immediately following the current row, but it could be
* implemented to insert new rows in any number of other places.
* <P>
* Another thing to note about these examples is how they use the method
* <code>acceptChanges. It is this method that propagates changes in
* a <code>CachedRowSet object back to the underlying data source,
* calling on the <code>RowSet object's writer internally to write
* changes to the data source. To do this, the writer has to incur the expense
* of establishing a connection with that data source. The
* preceding two code fragments call the method <code>acceptChanges
* immediately after calling <code>updateRow or insertRow.
* However, when there are multiple rows being changed, it is more efficient to call
* <code>acceptChanges after all calls to updateRow
* and <code>insertRow have been made. If acceptChanges
* is called only once, only one connection needs to be established.
*
* <h3>4.0 Updating the Underlying Data Source
* When the method <code>acceptChanges is executed, the
* <code>CachedRowSet object's writer, a RowSetWriterImpl
* object, is called behind the scenes to write the changes made to the
* rowset to the underlying data source. The writer is implemented to make a
* connection to the data source and write updates to it.
* <P>
* A writer is made available through an implementation of the
* <code>SyncProvider interface, as discussed in section 1,
* "Creating a <code>CachedRowSet Object."
* The default reference implementation provider, <code>RIOptimisticProvider,
* has its writer implemented to use an optimistic concurrency control
* mechanism. That is, it maintains no locks in the underlying database while
* the rowset is disconnected from the database and simply checks to see if there
* are any conflicts before writing data to the data source. If there are any
* conflicts, it does not write anything to the data source.
* <P>
* The reader/writer facility
* provided by the <code>SyncProvider class is pluggable, allowing for the
* customization of data retrieval and updating. If a different concurrency
* control mechanism is desired, a different implementation of
* <code>SyncProvider can be plugged in using the method
* <code>setSyncProvider.
* <P>
* In order to use the optimistic concurrency control routine, the
* <code>RIOptismisticProvider maintains both its current
* value and its original value (the value it had immediately preceding the
* current value). Note that if no changes have been made to the data in a
* <code>RowSet object, its current values and its original values are the same,
* both being the values with which the <code>RowSet object was initially
* populated. However, once any values in the <code>RowSet object have been
* changed, the current values and the original values will be different, though at
* this stage, the original values are still the initial values. With any subsequent
* changes to data in a <code>RowSet object, its original values and current
* values will still differ, but its original values will be the values that
* were previously the current values.
* <P>
* Keeping track of original values allows the writer to compare the <code>RowSet
* object's original value with the value in the database. If the values in
* the database differ from the <code>RowSet object's original values, which means that
* the values in the database have been changed, there is a conflict.
* Whether a writer checks for conflicts, what degree of checking it does, and how
* it handles conflicts all depend on how it is implemented.
*
* <h3>5.0 Registering and Notifying Listeners
* Being JavaBeans components, all rowsets participate in the JavaBeans event
* model, inheriting methods for registering listeners and notifying them of
* changes from the <code>BaseRowSet class. A listener for a
* <code>CachedRowSet object is a component that wants to be notified
* whenever there is a change in the rowset. For example, if a
* <code>CachedRowSet object contains the results of a query and
* those
* results are being displayed in, say, a table and a bar graph, the table and
* bar graph could be registered as listeners with the rowset so that they can
* update themselves to reflect changes. To become listeners, the table and
* bar graph classes must implement the <code>RowSetListener interface.
* Then they can be added to the <Code>CachedRowSet object's list of
* listeners, as is illustrated in the following lines of code.
* <PRE>
* crs.addRowSetListener(table);
* crs.addRowSetListener(barGraph);
* </PRE>
* Each <code>CachedRowSet method that moves the cursor or changes
* data also notifies registered listeners of the changes, so
* <code>table and barGraph will be notified when there is
* a change in <code>crs.
*
* <h3>6.0 Passing Data to Thin Clients
* One of the main reasons to use a <code>CachedRowSet object is to
* pass data between different components of an application. Because it is
* serializable, a <code>CachedRowSet object can be used, for example,
* to send the result of a query executed by an enterprise JavaBeans component
* running in a server environment over a network to a client running in a
* web browser.
* <P>
* While a <code>CachedRowSet object is disconnected, it can be much
* leaner than a <code>ResultSet object with the same data.
* As a result, it can be especially suitable for sending data to a thin client
* such as a PDA, where it would be inappropriate to use a JDBC driver
* due to resource limitations or security considerations.
* Thus, a <code>CachedRowSet object provides a means to "get rows in"
* without the need to implement the full JDBC API.
*
* <h3>7.0 Scrolling and Updating
* A second major use for <code>CachedRowSet objects is to provide
* scrolling and updating for <code>ResultSet objects that
* do not provide these capabilities themselves. In other words, a
* <code>CachedRowSet object can be used to augment the
* capabilities of a JDBC technology-enabled driver (hereafter called a
* "JDBC driver") when the DBMS does not provide full support for scrolling and
* updating. To achieve the effect of making a non-scrollble and read-only
* <code>ResultSet object scrollable and updatable, a programmer
* simply needs to create a <code>CachedRowSet object populated
* with that <code>ResultSet object's data. This is demonstrated
* in the following code fragment, where <code>stmt is a
* <code>Statement object.
* <PRE>
* ResultSet rs = stmt.executeQuery("SELECT * FROM EMPLOYEES");
* CachedRowSetImpl crs = new CachedRowSetImpl();
* crs.populate(rs);
* </PRE>
* <P>
* The object <code>crs now contains the data from the table
* <code>EMPLOYEES, just as the object rs does.
* The difference is that the cursor for <code>crs can be moved
* forward, backward, or to a particular row even if the cursor for
* <code>rs can move only forward. In addition, crs is
* updatable even if <code>rs is not because by default, a
* <code>CachedRowSet object is both scrollable and updatable.
* <P>
* In summary, a <code>CachedRowSet object can be thought of as simply
* a disconnected set of rows that are being cached outside of a data source.
* Being thin and serializable, it can easily be sent across a wire,
* and it is well suited to sending data to a thin client. However, a
* <code>CachedRowSet object does have a limitation: It is limited in
* size by the amount of data it can store in memory at one time.
*
* <h3>8.0 Getting Universal Data Access
* Another advantage of the <code>CachedRowSet class is that it makes it
* possible to retrieve and store data from sources other than a relational
* database. The reader for a rowset can be implemented to read and populate
* its rowset with data from any tabular data source, including a spreadsheet
* or flat file.
* Because both a <code>CachedRowSet object and its metadata can be
* created from scratch, a component that acts as a factory for rowsets
* can use this capability to create a rowset containing data from
* non-SQL data sources. Nevertheless, it is expected that most of the time,
* <code>CachedRowSet objects will contain data that was fetched
* from an SQL database using the JDBC API.
*
* <h3>9.0 Setting Properties
* All rowsets maintain a set of properties, which will usually be set using
* a tool. The number and kinds of properties a rowset has will vary,
* depending on what the rowset does and how it gets its data. For example,
* rowsets that get their data from a <code>ResultSet object need to
* set the properties that are required for making a database connection.
* If a rowset uses the <code>DriverManager facility to make a
* connection, it needs to set a property for the JDBC URL that identifies
* the appropriate driver, and it needs to set the properties that give the
* user name and password.
* If, on the other hand, the rowset uses a <code>DataSource object
* to make the connection, which is the preferred method, it does not need to
* set the property for the JDBC URL. Instead, it needs to set
* properties for the logical name of the data source, for the user name,
* and for the password.
* <P>
* NOTE: In order to use a <code>DataSource object for making a
* connection, the <code>DataSource object must have been registered
* with a naming service that uses the Java Naming and Directory
* Interface™ (JNDI) API. This registration
* is usually done by a person acting in the capacity of a system
* administrator.
* <P>
* In order to be able to populate itself with data from a database, a rowset
* needs to set a command property. This property is a query that is a
* <code>PreparedStatement object, which allows the query to have
* parameter placeholders that are set at run time, as opposed to design time.
* To set these placeholder parameters with values, a rowset provides
* setter methods for setting values of each data type,
* similar to the setter methods provided by the <code>PreparedStatement
* interface.
* <P>
* The following code fragment illustrates how the <code>CachedRowSet
* object <code>crs might have its command property set. Note that if a
* tool is used to set properties, this is the code that the tool would use.
* <PRE>{@code
* crs.setCommand("SELECT FIRST_NAME, LAST_NAME, ADDRESS FROM CUSTOMERS " +
* "WHERE CREDIT_LIMIT > ? AND REGION = ?");
* } </PRE>
* <P>
* The values that will be used to set the command's placeholder parameters are
* contained in the <code>RowSet object's params field, which is a
* <code>Vector object.
* The <code>CachedRowSet class provides a set of setter
* methods for setting the elements in its <code>params field. The
* following code fragment demonstrates setting the two parameters in the
* query from the previous example.
* <PRE>
* crs.setInt(1, 5000);
* crs.setString(2, "West");
* </PRE>
* <P>
* The <code>params field now contains two elements, each of which is
* an array two elements long. The first element is the parameter number;
* the second is the value to be set.
* In this case, the first element of <code>params is
* <code>1, 5000, and the second element is 2,
* <code>"West". When an application calls the method
* <code>execute, it will in turn call on this RowSet object's reader,
* which will in turn invoke its <code>readData method. As part of
* its implementation, <code>readData will get the values in
* <code>params and use them to set the command's placeholder
* parameters.
* The following code fragment gives an idea of how the reader
* does this, after obtaining the <code>Connection object
* <code>con.
* <PRE>{@code
* PreparedStatement pstmt = con.prepareStatement(crs.getCommand());
* reader.decodeParams();
* // decodeParams figures out which setter methods to use and does something
* // like the following:
* // for (i = 0; i < params.length; i++) {
* // pstmt.setObject(i + 1, params[i]);
* // }
* }</PRE>
* <P>
* At this point, the command for <code>crs is the query {@code "SELECT
* FIRST_NAME, LAST_NAME, ADDRESS FROM CUSTOMERS WHERE CREDIT_LIMIT > 5000
* AND REGION = "West"}. After the <code>readData method executes
* this command with the following line of code, it will have the data from
* <code>rs with which to populate crs.
* <PRE>{@code
* ResultSet rs = pstmt.executeQuery();
* }</PRE>
* <P>
* The preceding code fragments give an idea of what goes on behind the
* scenes; they would not appear in an application, which would not invoke
* methods like <code>readData and decodeParams.
* In contrast, the following code fragment shows what an application might do.
* It sets the rowset's command, sets the command's parameters, and executes
* the command. Simply by calling the <code>execute method,
* <code>crs populates itself with the requested data from the
* table <code>CUSTOMERS.
* <PRE>{@code
* crs.setCommand("SELECT FIRST_NAME, LAST_NAME, ADDRESS FROM CUSTOMERS" +
* "WHERE CREDIT_LIMIT > ? AND REGION = ?");
* crs.setInt(1, 5000);
* crs.setString(2, "West");
* crs.execute();
* }</PRE>
*
* <h3>10.0 Paging Data
* Because a <code>CachedRowSet object stores data in memory,
* the amount of data that it can contain at any one
* time is determined by the amount of memory available. To get around this limitation,
* a <code>CachedRowSet object can retrieve data from a ResultSet
* object in chunks of data, called <i>pages. To take advantage of this mechanism,
* an application sets the number of rows to be included in a page using the method
* <code>setPageSize. In other words, if the page size is set to five, a chunk
* of five rows of
* data will be fetched from the data source at one time. An application can also
* optionally set the maximum number of rows that may be fetched at one time. If the
* maximum number of rows is set to zero, or no maximum number of rows is set, there is
* no limit to the number of rows that may be fetched at a time.
* <P>
* After properties have been set,
* the <code>CachedRowSet object must be populated with data
* using either the method <code>populate or the method execute.
* The following lines of code demonstrate using the method <code>populate.
* Note that this version of the method takes two parameters, a <code>ResultSet
* handle and the row in the <code>ResultSet object from which to start
* retrieving rows.
* <PRE>
* CachedRowSet crs = new CachedRowSetImpl();
* crs.setMaxRows(20);
* crs.setPageSize(4);
* crs.populate(rsHandle, 10);
* </PRE>
* When this code runs, <i>crs will be populated with four rows from
* <i>rsHandle starting with the tenth row.
* <P>
* The next code fragment shows populating a <code>CachedRowSet object using the
* method <code>execute, which may or may not take a Connection
* object as a parameter. This code passes <code>execute the Connection
* object <i>conHandle.
* <P>
* Note that there are two differences between the following code
* fragment and the previous one. First, the method <code>setMaxRows is not
* called, so there is no limit set for the number of rows that <i>crs may contain.
* (Remember that <i>crs always has the overriding limit of how much data it can
* store in memory.) The second difference is that the you cannot pass the method
* <code>execute the number of the row in the ResultSet object
* from which to start retrieving rows. This method always starts with the first row.
* <PRE>
* CachedRowSet crs = new CachedRowSetImpl();
* crs.setPageSize(5);
* crs.execute(conHandle);
* </PRE>
* After this code has run, <i>crs will contain five rows of data from the
* <code>ResultSet object produced by the command for crs. The writer
* for <i>crs will use conHandle to connect to the data source and
* execute the command for <i>crs. An application is then able to operate on the
* data in <i>crs in the same way that it would operate on data in any other
* <code>CachedRowSet object.
* <P>
* To access the next page (chunk of data), an application calls the method
* <code>nextPage. This method creates a new CachedRowSet object
* and fills it with the next page of data. For example, assume that the
* <code>CachedRowSet object's command returns a ResultSet object
* <i>rs with 1000 rows of data. If the page size has been set to 100, the first
* call to the method <code>nextPage will create a CachedRowSet object
* containing the first 100 rows of <i>rs. After doing what it needs to do with the
* data in these first 100 rows, the application can again call the method
* <code>nextPage to create another CachedRowSet object
* with the second 100 rows from <i>rs. The data from the first CachedRowSet
* object will no longer be in memory because it is replaced with the data from the
* second <code>CachedRowSet object. After the tenth call to the method nextPage,
* the tenth <code>CachedRowSet object will contain the last 100 rows of data from
* <i>rs, which are stored in memory. At any given time, the data from only one
* <code>CachedRowSet object is stored in memory.
* <P>
* The method <code>nextPage returns true as long as the current
* page is not the last page of rows and <code>false when there are no more pages.
* It can therefore be used in a <code>while loop to retrieve all of the pages,
* as is demonstrated in the following lines of code.
* <PRE>
* CachedRowSet crs = CachedRowSetImpl();
* crs.setPageSize(100);
* crs.execute(conHandle);
*
* while(crs.nextPage()) {
* while(crs.next()) {
* . . . // operate on chunks (of 100 rows each) in crs,
* // row by row
* }
* }
* </PRE>
* After this code fragment has been run, the application will have traversed all
* 1000 rows, but it will have had no more than 100 rows in memory at a time.
* <P>
* The <code>CachedRowSet interface also defines the method previousPage.
* Just as the method <code>nextPage is analogous to the ResultSet
* method <code>next, the method previousPage is analogous to
* the <code>ResultSet method previous. Similar to the method
* <code>nextPage, previousPage creates a CachedRowSet
* object containing the number of rows set as the page size. So, for instance, the
* method <code>previousPage could be used in a while loop at
* the end of the preceding code fragment to navigate back through the pages from the last
* page to the first page.
* The method <code>previousPage is also similar to nextPage
* in that it can be used in a <code>while
* loop, except that it returns <code>true as long as there is another page
* preceding it and <code>false when there are no more pages ahead of it.
* <P>
* By positioning the cursor after the last row for each page,
* as is done in the following code fragment, the method <code>previous
* navigates from the last row to the first row in each page.
* The code could also have left the cursor before the first row on each page and then
* used the method <code>next in a while loop to navigate each page
* from the first row to the last row.
* <P>
* The following code fragment assumes a continuation from the previous code fragment,
* meaning that the cursor for the tenth <code>CachedRowSet object is on the
* last row. The code moves the cursor to after the last row so that the first
* call to the method <code>previous will put the cursor back on the last row.
* After going through all of the rows in the last page (the <code>CachedRowSet
* object <i>crs), the code then enters
* the <code>while loop to get to the ninth page, go through the rows backwards,
* go to the eighth page, go through the rows backwards, and so on to the first row
* of the first page.
*
* <PRE>
* crs.afterLast();
* while(crs.previous()) {
* . . . // navigate through the rows, last to first
* {
* while(crs.previousPage()) {
* crs.afterLast();
* while(crs.previous()) {
* . . . // go from the last row to the first row of each page
* }
* }
* </PRE>
*
* @author Jonathan Bruce
*/
public interface CachedRowSet extends RowSet, Joinable {
/**
* Populates this <code>CachedRowSet object with data from
* the given <code>ResultSet object.
* <P>
* This method can be used as an alternative to the <code>execute method when an
* application has a connection to an open <code>ResultSet object.
* Using the method <code>populate can be more efficient than using
* the version of the <code>execute method that takes no parameters
* because it does not open a new connection and re-execute this
* <code>CachedRowSet object's command. Using the populate
* method is more a matter of convenience when compared to using the version
* of <code>execute that takes a ResultSet object.
*
* @param data the <code>ResultSet object containing the data
* to be read into this <code>CachedRowSet object
* @throws SQLException if a null <code>ResultSet object is supplied
* or this <code>CachedRowSet object cannot
* retrieve the associated <code>ResultSetMetaData object
* @see #execute
* @see java.sql.ResultSet
* @see java.sql.ResultSetMetaData
*/
public void populate(ResultSet data) throws SQLException;
/**
* Populates this <code>CachedRowSet object with data, using the
* given connection to produce the result set from which the data will be read.
* This method should close any database connections that it creates to
* ensure that this <code>CachedRowSet object is disconnected except when
* it is reading data from its data source or writing data to its data source.
* <P>
* The reader for this <code>CachedRowSet object
* will use <i>conn to establish a connection to the data source
* so that it can execute the rowset's command and read data from the
* the resulting <code>ResultSet object into this
* <code>CachedRowSet object. This method also closes conn
* after it has populated this <code>CachedRowSet object.
* <P>
* If this method is called when an implementation has already been
* populated, the contents and the metadata are (re)set. Also, if this method is
* called before the method <code>acceptChanges has been called
* to commit outstanding updates, those updates are lost.
*
* @param conn a standard JDBC <code>Connection object with valid
* properties
* @throws SQLException if an invalid <code>Connection object is supplied
* or an error occurs in establishing the connection to the
* data source
* @see #populate
* @see java.sql.Connection
*/
public void execute(Connection conn) throws SQLException;
/**
* Propagates row update, insert and delete changes made to this
* <code>CachedRowSet object to the underlying data source.
* <P>
* This method calls on this <code>CachedRowSet object's writer
* to do the work behind the scenes.
* Standard <code>CachedRowSet implementations should use the
* <code>SyncFactory singleton
* to obtain a <code>SyncProvider instance providing a
* <code>RowSetWriter object (writer). The writer will attempt
* to propagate changes made in this <code>CachedRowSet object
* back to the data source.
* <P>
* When the method <code>acceptChanges executes successfully, in
* addition to writing changes to the data source, it
* makes the values in the current row be the values in the original row.
* <P>
* Depending on the synchronization level of the <code>SyncProvider
* implementation being used, the writer will compare the original values
* with those in the data source to check for conflicts. When there is a conflict,
* the <code>RIOptimisticProvider implementation, for example, throws a
* <code>SyncProviderException and does not write anything to the
* data source.
* <P>
* An application may choose to catch the <code>SyncProviderException
* object and retrieve the <code>SyncResolver object it contains.
* The <code>SyncResolver object lists the conflicts row by row and
* sets a lock on the data source to avoid further conflicts while the
* current conflicts are being resolved.
* Further, for each conflict, it provides methods for examining the conflict
* and setting the value that should be persisted in the data source.
* After all conflicts have been resolved, an application must call the
* <code>acceptChanges method again to write resolved values to the
* data source. If all of the values in the data source are already the
* values to be persisted, the method <code>acceptChanges does nothing.
* <P>
* Some provider implementations may use locks to ensure that there are no
* conflicts. In such cases, it is guaranteed that the writer will succeed in
* writing changes to the data source when the method <code>acceptChanges
* is called. This method may be called immediately after the methods
* <code>updateRow, insertRow, or deleteRow
* have been called, but it is more efficient to call it only once after
* all changes have been made so that only one connection needs to be
* established.
* <P>
* Note: The <code>acceptChanges() method will determine if the
* <code>COMMIT_ON_ACCEPT_CHANGES is set to true or not. If it is set
* to true, all updates in the synchronization are committed to the data
* source. Otherwise, the application <b>must explicity call the
* <code>commit() or rollback() methods as appropriate.
*
* @throws SyncProviderException if the underlying
* synchronization provider's writer fails to write the updates
* back to the data source
* @see #acceptChanges(java.sql.Connection)
* @see javax.sql.RowSetWriter
* @see javax.sql.rowset.spi.SyncFactory
* @see javax.sql.rowset.spi.SyncProvider
* @see javax.sql.rowset.spi.SyncProviderException
* @see javax.sql.rowset.spi.SyncResolver
*/
public void acceptChanges() throws SyncProviderException;
/**
* Propagates all row update, insert and delete changes to the
* data source backing this <code>CachedRowSet object
* using the specified <code>Connection object to establish a
* connection to the data source.
* <P>
* The other version of the <code>acceptChanges method is not passed
* a connection because it uses
* the <code>Connection object already defined within the RowSet
* object, which is the connection used for populating it initially.
* <P>
* This form of the method <code>acceptChanges is similar to the
* form that takes no arguments; however, unlike the other form, this form
* can be used only when the underlying data source is a JDBC data source.
* The updated <code>Connection properties must be used by the
* <code>SyncProvider to reset the RowSetWriter
* configuration to ensure that the contents of the <code>CachedRowSet
* object are synchronized correctly.
* <P>
* When the method <code>acceptChanges executes successfully, in
* addition to writing changes to the data source, it
* makes the values in the current row be the values in the original row.
* <P>
* Depending on the synchronization level of the <code>SyncProvider
* implementation being used, the writer will compare the original values
* with those in the data source to check for conflicts. When there is a conflict,
* the <code>RIOptimisticProvider implementation, for example, throws a
* <code>SyncProviderException and does not write anything to the
* data source.
* <P>
* An application may choose to catch the <code>SyncProviderException
* object and retrieve the <code>SyncResolver object it contains.
* The <code>SyncResolver object lists the conflicts row by row and
* sets a lock on the data source to avoid further conflicts while the
* current conflicts are being resolved.
* Further, for each conflict, it provides methods for examining the conflict
* and setting the value that should be persisted in the data source.
* After all conflicts have been resolved, an application must call the
* <code>acceptChanges method again to write resolved values to the
* data source. If all of the values in the data source are already the
* values to be persisted, the method <code>acceptChanges does nothing.
* <P>
* Some provider implementations may use locks to ensure that there are no
* conflicts. In such cases, it is guaranteed that the writer will succeed in
* writing changes to the data source when the method <code>acceptChanges
* is called. This method may be called immediately after the methods
* <code>updateRow, insertRow, or deleteRow
* have been called, but it is more efficient to call it only once after
* all changes have been made so that only one connection needs to be
* established.
* <P>
* Note: The <code>acceptChanges() method will determine if the
* <code>COMMIT_ON_ACCEPT_CHANGES is set to true or not. If it is set
* to true, all updates in the synchronization are committed to the data
* source. Otherwise, the application <b>must explicity call the
* <code>commit or rollback methods as appropriate.
*
* @param con a standard JDBC <code>Connection object
* @throws SyncProviderException if the underlying
* synchronization provider's writer fails to write the updates
* back to the data source
* @see #acceptChanges()
* @see javax.sql.RowSetWriter
* @see javax.sql.rowset.spi.SyncFactory
* @see javax.sql.rowset.spi.SyncProvider
* @see javax.sql.rowset.spi.SyncProviderException
* @see javax.sql.rowset.spi.SyncResolver
*/
public void acceptChanges(Connection con) throws SyncProviderException;
/**
* Restores this <code>CachedRowSet object to its original
* value, that is, its value before the last set of changes. If there
* have been no changes to the rowset or only one set of changes,
* the original value is the value with which this <code>CachedRowSet object
* was populated; otherwise, the original value is
* the value it had immediately before its current value.
* <P>
* When this method is called, a <code>CachedRowSet implementation
* must ensure that all updates, inserts, and deletes to the current
* rowset instance are replaced by the previous values. In addition,
* the cursor should be
* reset to the first row and a <code>rowSetChanged event
* should be fired to notify all registered listeners.
*
* @throws SQLException if an error occurs rolling back the current value of
* this <code>CachedRowSet object to its previous value
* @see javax.sql.RowSetListener#rowSetChanged
*/
public void restoreOriginal() throws SQLException;
/**
* Releases the current contents of this <code>CachedRowSet
* object and sends a <code>rowSetChanged event to all
* registered listeners. Any outstanding updates are discarded and
* the rowset contains no rows after this method is called. There
* are no interactions with the underlying data source, and any rowset
* content, metadata, and content updates should be non-recoverable.
* <P>
* This <code>CachedRowSet object should lock until its contents and
* associated updates are fully cleared, thus preventing 'dirty' reads by
* other components that hold a reference to this <code>RowSet object.
* In addition, the contents cannot be released
* until all all components reading this <code>CachedRowSet object
* have completed their reads. This <code>CachedRowSet object
* should be returned to normal behavior after firing the
* <code>rowSetChanged event.
* <P>
* The metadata, including JDBC properties and Synchronization SPI
* properties, are maintained for future use. It is important that
* properties such as the <code>command property be
* relevant to the originating data source from which this <code>CachedRowSet
* object was originally established.
* <P>
* This method empties a rowset, as opposed to the <code>close method,
* which marks the entire rowset as recoverable to allow the garbage collector
* the rowset's Java VM resources.
*
* @throws SQLException if an error occurs flushing the contents of this
* <code>CachedRowSet object
* @see javax.sql.RowSetListener#rowSetChanged
* @see java.sql.ResultSet#close
*/
public void release() throws SQLException;
/**
* Cancels the deletion of the current row and notifies listeners that
* a row has changed. After this method is called, the current row is
* no longer marked for deletion. This method can be called at any
* time during the lifetime of the rowset.
* <P>
* In addition, multiple cancellations of row deletions can be made
* by adjusting the position of the cursor using any of the cursor
* position control methods such as:
* <ul>
* <li>CachedRowSet.absolute
* <li>CachedRowSet.first
* <li>CachedRowSet.last
* </ul>
*
* @throws SQLException if (1) the current row has not been deleted or
* (2) the cursor is on the insert row, before the first row, or
* after the last row
* @see javax.sql.rowset.CachedRowSet#undoInsert
* @see java.sql.ResultSet#cancelRowUpdates
*/
public void undoDelete() throws SQLException;
/**
* Immediately removes the current row from this <code>CachedRowSet
* object if the row has been inserted, and also notifies listeners that a
* row has changed. This method can be called at any time during the
* lifetime of a rowset and assuming the current row is within
* the exception limitations (see below), it cancels the row insertion
* of the current row.
* <P>
* In addition, multiple cancellations of row insertions can be made
* by adjusting the position of the cursor using any of the cursor
* position control methods such as:
* <ul>
* <li>CachedRowSet.absolute
* <li>CachedRowSet.first
* <li>CachedRowSet.last
* </ul>
*
* @throws SQLException if (1) the current row has not been inserted or (2)
* the cursor is before the first row, after the last row, or on the
* insert row
* @see javax.sql.rowset.CachedRowSet#undoDelete
* @see java.sql.ResultSet#cancelRowUpdates
*/
public void undoInsert() throws SQLException;
/**
* Immediately reverses the last update operation if the
* row has been modified. This method can be
* called to reverse updates on all columns until all updates in a row have
* been rolled back to their state just prior to the last synchronization
* (<code>acceptChanges) or population. This method may also be called
* while performing updates to the insert row.
* <P>
* <code>undoUpdate may be called at any time during the lifetime of a
* rowset; however, after a synchronization has occurred, this method has no
* effect until further modification to the rowset data has occurred.
*
* @throws SQLException if the cursor is before the first row or after the last
* row in in this <code>CachedRowSet object
* @see #undoDelete
* @see #undoInsert
* @see java.sql.ResultSet#cancelRowUpdates
*/
public void undoUpdate() throws SQLException;
/**
* Indicates whether the designated column in the current row of this
* <code>CachedRowSet object has been updated.
*
* @param idx an <code>int identifying the column to be checked for updates
* @return <code>true if the designated column has been visibly updated;
* <code>false otherwise
* @throws SQLException if the cursor is on the insert row, before the first row,
* or after the last row
* @see java.sql.DatabaseMetaData#updatesAreDetected
*/
public boolean columnUpdated(int idx) throws SQLException;
/**
* Indicates whether the designated column in the current row of this
* <code>CachedRowSet object has been updated.
*
* @param columnName a <code>String object giving the name of the
* column to be checked for updates
* @return <code>true if the column has been visibly updated;
* <code>false otherwise
* @throws SQLException if the cursor is on the insert row, before the first row,
* or after the last row
* @see java.sql.DatabaseMetaData#updatesAreDetected
*/
public boolean columnUpdated(String columnName) throws SQLException;
/**
* Converts this <code>CachedRowSet object to a Collection
* object that contains all of this <code>CachedRowSet object's data.
* Implementations have some latitude in
* how they can represent this <code>Collection object because of the
* abstract nature of the <code>Collection framework.
* Each row must be fully represented in either a
* general purpose <code>Collection implementation or a specialized
* <code>Collection implementation, such as a TreeMap
* object or a <code>Vector object.
* An SQL <code>NULL column value must be represented as a null
* in the Java programming language.
* <P>
* The standard reference implementation for the <code>CachedRowSet
* interface uses a <code>TreeMap object for the rowset, with the
* values in each row being contained in <code>Vector objects. It is
* expected that most implementations will do the same.
* <P>
* The <code>TreeMap type of collection guarantees that the map will be in
* ascending key order, sorted according to the natural order for the
* key's class.
* Each key references a <code>Vector object that corresponds to one
* row of a <code>RowSet object. Therefore, the size of each
* <code>Vector object must be exactly equal to the number of
* columns in the <code>RowSet object.
* The key used by the <code>TreeMap collection is determined by the
* implementation, which may choose to leverage a set key that is
* available within the internal <code>RowSet tabular structure by
* virtue of a key already set either on the <code>RowSet object
* itself or on the underlying SQL data.
* <P>
*
* @return a <code>Collection object that contains the values in
* each row in this <code>CachedRowSet object
* @throws SQLException if an error occurs generating the collection
* @see #toCollection(int)
* @see #toCollection(String)
*/
public Collection<?> toCollection() throws SQLException;
/**
* Converts the designated column in this <code>CachedRowSet object
* to a <code>Collection object. Implementations have some latitude in
* how they can represent this <code>Collection object because of the
* abstract nature of the <code>Collection framework.
* Each column value should be fully represented in either a
* general purpose <code>Collection implementation or a specialized
* <code>Collection implementation, such as a Vector object.
* An SQL <code>NULL column value must be represented as a null
* in the Java programming language.
* <P>
* The standard reference implementation uses a <code>Vector object
* to contain the column values, and it is expected
* that most implementations will do the same. If a <code>Vector object
* is used, it size must be exactly equal to the number of rows
* in this <code>CachedRowSet object.
*
* @param column an <code>int indicating the column whose values
* are to be represented in a <code>Collection object
* @return a <code>Collection object that contains the values
* stored in the specified column of this <code>CachedRowSet
* object
* @throws SQLException if an error occurs generating the collection or
* an invalid column id is provided
* @see #toCollection
* @see #toCollection(String)
*/
public Collection<?> toCollection(int column) throws SQLException;
/**
* Converts the designated column in this <code>CachedRowSet object
* to a <code>Collection object. Implementations have some latitude in
* how they can represent this <code>Collection object because of the
* abstract nature of the <code>Collection framework.
* Each column value should be fully represented in either a
* general purpose <code>Collection implementation or a specialized
* <code>Collection implementation, such as a Vector object.
* An SQL <code>NULL column value must be represented as a null
* in the Java programming language.
* <P>
* The standard reference implementation uses a <code>Vector object
* to contain the column values, and it is expected
* that most implementations will do the same. If a <code>Vector object
* is used, it size must be exactly equal to the number of rows
* in this <code>CachedRowSet object.
*
* @param column a <code>String object giving the name of the
* column whose values are to be represented in a collection
* @return a <code>Collection object that contains the values
* stored in the specified column of this <code>CachedRowSet
* object
* @throws SQLException if an error occurs generating the collection or
* an invalid column id is provided
* @see #toCollection
* @see #toCollection(int)
*/
public Collection<?> toCollection(String column) throws SQLException;
/**
* Retrieves the <code>SyncProvider implementation for this
* <code>CachedRowSet object. Internally, this method is used by a rowset
* to trigger read or write actions between the rowset
* and the data source. For example, a rowset may need to get a handle
* on the the rowset reader (<code>RowSetReader object) from the
* <code>SyncProvider to allow the rowset to be populated.
* <pre>
* RowSetReader rowsetReader = null;
* SyncProvider provider =
* SyncFactory.getInstance("javax.sql.rowset.provider.RIOptimisticProvider");
* if (provider instanceof RIOptimisticProvider) {
* rowsetReader = provider.getRowSetReader();
* }
* </pre>
* Assuming <i>rowsetReader is a private, accessible field within
* the rowset implementation, when an application calls the <code>execute
* method, it in turn calls on the reader's <code>readData method
* to populate the <code>RowSet object.
*<pre>
* rowsetReader.readData((RowSetInternal)this);
* </pre>
* <P>
* In addition, an application can use the <code>SyncProvider object
* returned by this method to call methods that return information about the
* <code>SyncProvider object, including information about the
* vendor, version, provider identification, synchronization grade, and locks
* it currently has set.
*
* @return the <code>SyncProvider object that was set when the rowset
* was instantiated, or if none was was set, the default provider
* @throws SQLException if an error occurs while returning the
* <code>SyncProvider object
* @see #setSyncProvider
*/
public SyncProvider getSyncProvider() throws SQLException;
/**
* Sets the <code>SyncProvider object for this CachedRowSet
* object to the one specified. This method
* allows the <code>SyncProvider object to be reset.
* <P>
* A <code>CachedRowSet implementation should always be instantiated
* with an available <code>SyncProvider mechanism, but there are
* cases where resetting the <code>SyncProvider object is desirable
* or necessary. For example, an application might want to use the default
* <code>SyncProvider object for a time and then choose to use a provider
* that has more recently become available and better fits its needs.
* <P>
* Resetting the <code>SyncProvider object causes the
* <code>RowSet object to request a new SyncProvider implementation
* from the <code>SyncFactory. This has the effect of resetting
* all previous connections and relationships with the originating
* data source and can potentially drastically change the synchronization
* behavior of a disconnected rowset.
*
* @param provider a <code>String object giving the fully qualified class
* name of a <code>SyncProvider implementation
* @throws SQLException if an error occurs while attempting to reset the
* <code>SyncProvider implementation
* @see #getSyncProvider
*/
public void setSyncProvider(String provider) throws SQLException;
/**
* Returns the number of rows in this <code>CachedRowSet
* object.
*
* @return number of rows in the rowset
*/
public int size();
/**
* Sets the metadata for this <code>CachedRowSet object with
* the given <code>RowSetMetaData object. When a
* <code>RowSetReader object is reading the contents of a rowset,
* it creates a <code>RowSetMetaData object and initializes
* it using the methods in the <code>RowSetMetaData implementation.
* The reference implementation uses the <code>RowSetMetaDataImpl
* class. When the reader has completed reading the rowset contents,
* this method is called internally to pass the <code>RowSetMetaData
* object to the rowset.
*
* @param md a <code>RowSetMetaData object containing
* metadata about the columns in this <code>CachedRowSet object
* @throws SQLException if invalid metadata is supplied to the
* rowset
*/
public void setMetaData(RowSetMetaData md) throws SQLException;
/**
* Returns a <code>ResultSet object containing the original value of this
* <code>CachedRowSet object.
* <P>
* The cursor for the <code>ResultSet
* object should be positioned before the first row.
* In addition, the returned <code>ResultSet object should have the following
* properties:
* <UL>
* <LI>ResultSet.TYPE_SCROLL_INSENSITIVE
* <LI>ResultSet.CONCUR_UPDATABLE
* </UL>
* <P>
* The original value for a <code>RowSet object is the value it had before
* the last synchronization with the underlying data source. If there have been
* no synchronizations, the original value will be the value with which the
* <code>RowSet object was populated. This method is called internally
* when an application calls the method <code>acceptChanges and the
* <code>SyncProvider object has been implemented to check for conflicts.
* If this is the case, the writer compares the original value with the value
* currently in the data source to check for conflicts.
*
* @return a <code>ResultSet object that contains the original value for
* this <code>CachedRowSet object
* @throws SQLException if an error occurs producing the
* <code>ResultSet object
*/
public ResultSet getOriginal() throws SQLException;
/**
* Returns a <code>ResultSet object containing the original value for the
* current row only of this <code>CachedRowSet object.
* <P>
* The cursor for the <code>ResultSet
* object should be positioned before the first row.
* In addition, the returned <code>ResultSet object should have the following
* properties:
* <UL>
* <LI>ResultSet.TYPE_SCROLL_INSENSITIVE
* <LI>ResultSet.CONCUR_UPDATABLE
* </UL>
*
* @return the original result set of the row
* @throws SQLException if there is no current row
* @see #setOriginalRow
*/
public ResultSet getOriginalRow() throws SQLException;
/**
* Sets the current row in this <code>CachedRowSet object as the original
* row.
* <P>
* This method is called internally after the any modified values in the current
* row have been synchronized with the data source. The current row must be tagged
* as no longer inserted, deleted or updated.
* <P>
* A call to <code>setOriginalRow is irreversible.
*
* @throws SQLException if there is no current row or an error is
* encountered resetting the contents of the original row
* @see #getOriginalRow
*/
public void setOriginalRow() throws SQLException;
/**
* Returns an identifier for the object (table) that was used to
* create this <code>CachedRowSet object. This name may be set on multiple occasions,
* and the specification imposes no limits on how many times this
* may occur or whether standard implementations should keep track
* of previous table names.
*
* @return a <code>String object giving the name of the table that is the
* source of data for this <code>CachedRowSet object or null
* if no name has been set for the table
* @throws SQLException if an error is encountered returning the table name
* @see javax.sql.RowSetMetaData#getTableName
*/
public String getTableName() throws SQLException;
/**
* Sets the identifier for the table from which this <code>CachedRowSet
* object was derived to the given table name. The writer uses this name to
* determine which table to use when comparing the values in the data source with the
* <code>CachedRowSet object's values during a synchronization attempt.
* The table identifier also indicates where modified values from this
* <code>CachedRowSet object should be written.
* <P>
* The implementation of this <code>CachedRowSet object may obtain the
* the name internally from the <code>RowSetMetaDataImpl object.
*
* @param tabName a <code>String object identifying the table from which this
<code>CachedRowSet object was derived; cannot be null
* but may be an empty string
* @throws SQLException if an error is encountered naming the table or
* <i>tabName is null
* @see javax.sql.RowSetMetaData#setTableName
* @see javax.sql.RowSetWriter
* @see javax.sql.rowset.spi.SyncProvider
*/
public void setTableName(String tabName) throws SQLException;
/**
* Returns an array containing one or more column numbers indicating the columns
* that form a key that uniquely
* identifies a row in this <code>CachedRowSet object.
*
* @return an array containing the column number or numbers that indicate which columns
* constitute a primary key
* for a row in this <code>CachedRowSet object. This array should be
* empty if no columns are representative of a primary key.
* @throws SQLException if this <code>CachedRowSet object is empty
* @see #setKeyColumns
* @see Joinable#getMatchColumnIndexes
* @see Joinable#getMatchColumnNames
*/
public int[] getKeyColumns() throws SQLException;
/**
* Sets this <code>CachedRowSet object's keyCols
* field with the given array of column numbers, which forms a key
* for uniquely identifying a row in this <code>CachedRowSet object.
* <p>
* If a <code>CachedRowSet object becomes part of a JoinRowSet
* object, the keys defined by this method and the resulting constraints are
* maintained if the columns designated as key columns also become match
* columns.
*
* @param keys an array of <code>int indicating the columns that form
* a primary key for this <code>CachedRowSet object; every
* element in the array must be greater than <code>0 and
* less than or equal to the number of columns in this rowset
* @throws SQLException if any of the numbers in the given array
* are not valid for this rowset
* @see #getKeyColumns
* @see Joinable#setMatchColumn(String)
* @see Joinable#setMatchColumn(int)
*/
public void setKeyColumns(int[] keys) throws SQLException;
/**
* Returns a new <code>RowSet object backed by the same data as
* that of this <code>CachedRowSet object. In effect, both
* <code>CachedRowSet objects have a cursor over the same data.
* As a result, any changes made by a duplicate are visible to the original
* and to any other duplicates, just as a change made by the original is visible
* to all of its duplicates. If a duplicate calls a method that changes the
* underlying data, the method it calls notifies all registered listeners
* just as it would when it is called by the original <code>CachedRowSet
* object.
* <P>
* In addition, any <code>RowSet object
* created by this method will have the same properties as this
* <code>CachedRowSet object. For example, if this CachedRowSet
* object is read-only, all of its duplicates will also be read-only. If it is
* changed to be updatable, the duplicates also become updatable.
* <P>
* NOTE: If multiple threads access <code>RowSet objects created from
* the <code>createShared() method, the following behavior is specified
* to preserve shared data integrity: reads and writes of all
* shared <code>RowSet objects should be made serially between each
* object and the single underlying tabular structure.
*
* @return a new shared <code>RowSet object that has the same properties
* as this <code>CachedRowSet object and that has a cursor over
* the same data
* @throws SQLException if an error occurs or cloning is not
* supported in the underlying platform
* @see javax.sql.RowSetEvent
* @see javax.sql.RowSetListener
*/
public RowSet createShared() throws SQLException;
/**
* Creates a <code>RowSet object that is a deep copy of the data in
* this <code>CachedRowSet object. In contrast to
* the <code>RowSet object generated from a createShared
* call, updates made to the copy of the original <code>RowSet object
* must not be visible to the original <code>RowSet object. Also, any
* event listeners that are registered with the original
* <code>RowSet must not have scope over the new
* <code>RowSet copies. In addition, any constraint restrictions
* established must be maintained.
*
* @return a new <code>RowSet object that is a deep copy
* of this <code>CachedRowSet object and is
* completely independent of this <code>CachedRowSet object
* @throws SQLException if an error occurs in generating the copy of
* the of this <code>CachedRowSet object
* @see #createShared
* @see #createCopySchema
* @see #createCopyNoConstraints
* @see javax.sql.RowSetEvent
* @see javax.sql.RowSetListener
*/
public CachedRowSet createCopy() throws SQLException;
/**
* Creates a <code>CachedRowSet object that is an empty copy of this
* <code>CachedRowSet object. The copy
* must not contain any contents but only represent the table
* structure of the original <code>CachedRowSet object. In addition, primary
* or foreign key constraints set in the originating <code>CachedRowSet object must
* be equally enforced in the new empty <code>CachedRowSet object.
* In contrast to
* the <code>RowSet object generated from a createShared method
* call, updates made to a copy of this <code>CachedRowSet object with the
* <code>createCopySchema method must not be visible to it.
* <P>
* Applications can form a <code>WebRowSet object from the CachedRowSet
* object returned by this method in order
* to export the <code>RowSet schema definition to XML for future use.
* @return An empty copy of this {@code CachedRowSet} object
* @throws SQLException if an error occurs in cloning the structure of this
* <code>CachedRowSet object
* @see #createShared
* @see #createCopySchema
* @see #createCopyNoConstraints
* @see javax.sql.RowSetEvent
* @see javax.sql.RowSetListener
*/
public CachedRowSet createCopySchema() throws SQLException;
/**
* Creates a <code>CachedRowSet object that is a deep copy of
* this <code>CachedRowSet object's data but is independent of it.
* In contrast to
* the <code>RowSet object generated from a createShared
* method call, updates made to a copy of this <code>CachedRowSet object
* must not be visible to it. Also, any
* event listeners that are registered with this
* <code>CachedRowSet object must not have scope over the new
* <code>RowSet object. In addition, any constraint restrictions
* established for this <code>CachedRowSet object must not be maintained
* in the copy.
*
* @return a new <code>CachedRowSet object that is a deep copy
* of this <code>CachedRowSet object and is
* completely independent of this <code>CachedRowSet object
* @throws SQLException if an error occurs in generating the copy of
* the of this <code>CachedRowSet object
* @see #createCopy
* @see #createShared
* @see #createCopySchema
* @see javax.sql.RowSetEvent
* @see javax.sql.RowSetListener
*/
public CachedRowSet createCopyNoConstraints() throws SQLException;
/**
* Retrieves the first warning reported by calls on this <code>RowSet object.
* Subsequent warnings on this <code>RowSet object will be chained to the
* <code>RowSetWarning object that this method returns.
*
* The warning chain is automatically cleared each time a new row is read.
* This method may not be called on a RowSet object that has been closed;
* doing so will cause a <code>SQLException to be thrown.
*
* @return RowSetWarning the first <code>RowSetWarning
* object reported or null if there are none
* @throws SQLException if this method is called on a closed RowSet
* @see RowSetWarning
*/
public RowSetWarning getRowSetWarnings() throws SQLException;
/**
* Retrieves a <code>boolean indicating whether rows marked
* for deletion appear in the set of current rows. If <code>true is
* returned, deleted rows are visible with the current rows. If
* <code>false is returned, rows are not visible with the set of
* current rows. The default value is <code>false.
* <P>
* Standard rowset implementations may choose to restrict this behavior
* due to security considerations or to better fit certain deployment
* scenarios. This is left as implementation defined and does not
* represent standard behavior.
* <P>
* Note: Allowing deleted rows to remain visible complicates the behavior
* of some standard JDBC <code>RowSet Implementations methods.
* However, most rowset users can simply ignore this extra detail because
* only very specialized applications will likely want to take advantage of
* this feature.
*
* @return <code>true if deleted rows are visible;
* <code>false otherwise
* @throws SQLException if a rowset implementation is unable to
* to determine whether rows marked for deletion are visible
* @see #setShowDeleted
*/
public boolean getShowDeleted() throws SQLException;
/**
* Sets the property <code>showDeleted to the given
* <code>boolean value, which determines whether
* rows marked for deletion appear in the set of current rows.
* If the value is set to <code>true, deleted rows are immediately
* visible with the set of current rows. If the value is set to
* <code>false, the deleted rows are set as invisible with the
* current set of rows.
* <P>
* Standard rowset implementations may choose to restrict this behavior
* due to security considerations or to better fit certain deployment
* scenarios. This is left as implementations defined and does not
* represent standard behavior.
*
* @param b <code>true if deleted rows should be shown;
* <code>false otherwise
* @exception SQLException if a rowset implementation is unable to
* to reset whether deleted rows should be visible
* @see #getShowDeleted
*/
public void setShowDeleted(boolean b) throws SQLException;
/**
* Each <code>CachedRowSet object's SyncProvider contains
* a <code>Connection object from the ResultSet or JDBC
* properties passed to it's constructors. This method wraps the
* <code>Connection commit method to allow flexible
* auto commit or non auto commit transactional control support.
* <p>
* Makes all changes that are performed by the <code>acceptChanges()
* method since the previous commit/rollback permanent. This method should
* be used only when auto-commit mode has been disabled.
*
* @throws SQLException if a database access error occurs or this
* Connection object within this <code>CachedRowSet is in auto-commit mode
* @see java.sql.Connection#setAutoCommit
*/
public void commit() throws SQLException;
/**
* Each <code>CachedRowSet object's SyncProvider contains
* a <code>Connection object from the original ResultSet
* or JDBC properties passed to it.
* <p>
* Undoes all changes made in the current transaction. This method
* should be used only when auto-commit mode has been disabled.
*
* @throws SQLException if a database access error occurs or this Connection
* object within this <code>CachedRowSet is in auto-commit mode.
*/
public void rollback() throws SQLException;
/**
* Each <code>CachedRowSet object's SyncProvider contains
* a <code>Connection object from the original ResultSet
* or JDBC properties passed to it.
* <p>
* Undoes all changes made in the current transaction back to the last
* <code>Savepoint transaction marker. This method should be used only
* when auto-commit mode has been disabled.
*
* @param s A <code>Savepoint transaction marker
* @throws SQLException if a database access error occurs or this Connection
* object within this <code>CachedRowSet is in auto-commit mode.
*/
public void rollback(Savepoint s) throws SQLException;
/**
* Causes the <code>CachedRowSet object's SyncProvider
* to commit the changes when <code>acceptChanges() is called. If
* set to false, the changes will <b>not be committed until one of the
* <code>CachedRowSet interface transaction methods is called.
*
* @deprecated Because this field is final (it is part of an interface),
* its value cannot be changed.
* @see #commit
* @see #rollback
*/
@Deprecated
public static final boolean COMMIT_ON_ACCEPT_CHANGES = true;
/**
* Notifies registered listeners that a RowSet object in the given RowSetEvent
* object has populated a number of additional rows. The <code>numRows parameter
* ensures that this event will only be fired every <code>numRow.
* <p>
* The source of the event can be retrieved with the method event.getSource.
*
* @param event a <code>RowSetEvent object that contains the
* <code>RowSet object that is the source of the events
* @param numRows when populating, the number of rows interval on which the
* <code>CachedRowSet populated should fire; the default value
* is zero; cannot be less than <code>fetchSize or zero
* @throws SQLException {@code numRows < 0 or numRows < getFetchSize() }
*/
public void rowSetPopulated(RowSetEvent event, int numRows) throws SQLException;
/**
* Populates this <code>CachedRowSet object with data from
* the given <code>ResultSet object. While related to the populate(ResultSet)
* method, an additional parameter is provided to allow starting position within
* the <code>ResultSet from where to populate the CachedRowSet
* instance.
* <P>
* This method can be used as an alternative to the <code>execute method when an
* application has a connection to an open <code>ResultSet object.
* Using the method <code>populate can be more efficient than using
* the version of the <code>execute method that takes no parameters
* because it does not open a new connection and re-execute this
* <code>CachedRowSet object's command. Using the populate
* method is more a matter of convenience when compared to using the version
* of <code>execute that takes a ResultSet object.
*
* @param startRow the position in the <code>ResultSet from where to start
* populating the records in this <code>CachedRowSet
* @param rs the <code>ResultSet object containing the data
* to be read into this <code>CachedRowSet object
* @throws SQLException if a null <code>ResultSet object is supplied
* or this <code>CachedRowSet object cannot
* retrieve the associated <code>ResultSetMetaData object
* @see #execute
* @see #populate(ResultSet)
* @see java.sql.ResultSet
* @see java.sql.ResultSetMetaData
*/
public void populate(ResultSet rs, int startRow) throws SQLException;
/**
* Sets the <code>CachedRowSet object's page-size. A CachedRowSet
* may be configured to populate itself in page-size sized batches of rows. When
* either <code>populate() or execute() are called, the
* <code>CachedRowSet fetches an additional page according to the
* original SQL query used to populate the RowSet.
*
* @param size the page-size of the <code>CachedRowSet
* @throws SQLException if an error occurs setting the <code>CachedRowSet
* page size or if the page size is less than 0.
*/
public void setPageSize(int size) throws SQLException;
/**
* Returns the page-size for the <code>CachedRowSet object
*
* @return an <code>int page size
*/
public int getPageSize();
/**
* Increments the current page of the <code>CachedRowSet. This causes
* the <code>CachedRowSet implementation to fetch the next page-size
* rows and populate the RowSet, if remaining rows remain within scope of the
* original SQL query used to populated the RowSet.
*
* @return true if more pages exist; false if this is the last page
* @throws SQLException if an error occurs fetching the next page, or if this
* method is called prematurely before populate or execute.
*/
public boolean nextPage() throws SQLException;
/**
* Decrements the current page of the <code>CachedRowSet. This causes
* the <code>CachedRowSet implementation to fetch the previous page-size
* rows and populate the RowSet. The amount of rows returned in the previous
* page must always remain within scope of the original SQL query used to
* populate the RowSet.
*
* @return true if the previous page is successfully retrieved; false if this
* is the first page.
* @throws SQLException if an error occurs fetching the previous page, or if
* this method is called prematurely before populate or execute.
*/
public boolean previousPage() throws SQLException;
}
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