Java example source code file (JoinRowSet.java)

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The JoinRowSet.java Java example source code

/*
 * Copyright (c) 2003, 2013, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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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.*;

/**
 * The <code>JoinRowSet interface provides a mechanism for combining related
 * data from different <code>RowSet objects into one JoinRowSet
 * object, which represents an SQL <code>JOIN.
 * In other words, a <code>JoinRowSet object acts as a
 * container for the data from <code>RowSet objects that form an SQL
 * <code>JOIN relationship.
 * <P>
 * The <code>Joinable interface provides the methods for setting,
 * retrieving, and unsetting a match column, the basis for
 * establishing an SQL <code>JOIN relationship. The match column may
 * alternatively be set by supplying it to the appropriate version of the
 * <code>JointRowSet method addRowSet.
 *
 * <h3>1.0 Overview
 * Disconnected <code>RowSet objects (CachedRowSet objects
 * and implementations extending the <code>CachedRowSet interface)
 * do not have a standard way to establish an SQL <code>JOIN between
 * <code>RowSet objects without the expensive operation of
 * reconnecting to the data source. The <code>JoinRowSet
 * interface is specifically designed to address this need.
 * <P>
 * Any <code>RowSet object
 * can be added to a <code>JoinRowSet object to become
 * part of an SQL <code>JOIN relationship. This means that both connected
 * and disconnected <code>RowSet objects can be part of a JOIN.
 * <code>RowSet objects operating in a connected environment
 * (<code>JdbcRowSet objects) are
 * encouraged to use the database to which they are already
 * connected to establish SQL <code>JOIN relationships between
 * tables directly. However, it is possible for a
 * <code>JdbcRowSet object to be added to a JoinRowSet object
 * if necessary.
 * <P>
 * Any number of <code>RowSet objects can be added to an
 * instance of <code>JoinRowSet provided that they
 * can be related in an SQL <code>JOIN.
 * By definition, the SQL <code>JOIN statement is used to
 * combine the data contained in two or more relational database tables based
 * upon a common attribute. The <code>Joinable interface provides the methods
 * for establishing a common attribute, which is done by setting a
 * <i>match column. The match column commonly coincides with
 * the primary key, but there is
 * no requirement that the match column be the same as the primary key.
 * By establishing and then enforcing column matches,
 * a <code>JoinRowSet object establishes JOIN relationships
 * between <code>RowSet objects without the assistance of an available
 * relational database.
 * <P>
 * The type of <code>JOIN to be established is determined by setting
 * one of the <code>JoinRowSet constants using the method
 * <code>setJoinType. The following SQL JOIN types can be set:
 * <UL>
 *  <LI>CROSS_JOIN
 *  <LI>FULL_JOIN
 *  <LI>INNER_JOIN - the default if no JOIN type has been set
 *  <LI>LEFT_OUTER_JOIN
 *  <LI>RIGHT_OUTER_JOIN
 * </UL>
 * Note that if no type is set, the <code>JOIN will automatically be an
 * inner join. The comments for the fields in the
 * <code>JoinRowSet interface explain these JOIN types, which are
 * standard SQL <code>JOIN types.
 *
 * <h3>2.0 Using a JoinRowSet Object for Creating a JOIN
 * When a <code>JoinRowSet object is created, it is empty.
 * The first <code>RowSet object to be added becomes the basis for the
 * <code>JOIN relationship.
 * Applications must determine which column in each of the
 * <code>RowSet objects to be added to the JoinRowSet object
 * should be the match column. All of the
 * <code>RowSet objects must contain a match column, and the values in
 * each match column must be ones that can be compared to values in the other match
 * columns. The columns do not have to have the same name, though they often do,
 * and they do not have to store the exact same data type as long as the data types
 * can be compared.
 * <P>
 * A match column can be be set in two ways:
 * <ul>
 *  <li>By calling the Joinable method setMatchColumn

 *  This is the only method that can set the match column before a <code>RowSet
 *  object is added to a <code>JoinRowSet object. The RowSet object
 *  must have implemented the <code>Joinable interface in order to use the method
 *  <code>setMatchColumn. Once the match column value
 *  has been set, this method can be used to reset the match column at any time.
 *  <li>By calling one of the versions of the JoinRowSet method
 *  <code>addRowSet that takes a column name or number (or an array of
 *  column names or numbers)<BR>
 *  Four of the five <code>addRowSet methods take a match column as a parameter.
 *  These four methods set or reset the match column at the time a <code>RowSet
 *  object is being added to a <code>JoinRowSet object.
 * </ul>
 * <h3>3.0 Sample Usage
 * <p>
 * The following code fragment adds two <code>CachedRowSet
 * objects to a <code>JoinRowSet object. Note that in this example,
 * no SQL <code>JOIN type is set, so the default JOIN type,
 * which is <i>INNER_JOIN, is established.
 * <p>
 * In the following code fragment, the table <code>EMPLOYEES, whose match
 * column is set to the first column (<code>EMP_ID), is added to the
 * <code>JoinRowSet object jrs. Then
 * the table <code>ESSP_BONUS_PLAN, whose match column is likewise
 * the <code>EMP_ID column, is added. When this second
 * table is added to <i>jrs, only the rows in
 * <code>ESSP_BONUS_PLAN whose EMP_ID value matches an
 * <code>EMP_ID value in the EMPLOYEES table are added.
 * In this case, everyone in the bonus plan is an employee, so all of the rows
 * in the table <code>ESSP_BONUS_PLAN are added to the JoinRowSet
 * object.  In this example, both <code>CachedRowSet objects being added
 * have implemented the <code>Joinable interface and can therefore call
 * the <code>Joinable method setMatchColumn.
 * <PRE>
 *     JoinRowSet jrs = new JoinRowSetImpl();
 *
 *     ResultSet rs1 = stmt.executeQuery("SELECT * FROM EMPLOYEES");
 *     CachedRowSet empl = new CachedRowSetImpl();
 *     empl.populate(rs1);
 *     empl.setMatchColumn(1);
 *     jrs.addRowSet(empl);
 *
 *     ResultSet rs2 = stmt.executeQuery("SELECT * FROM ESSP_BONUS_PLAN");
 *     CachedRowSet bonus = new CachedRowSetImpl();
 *     bonus.populate(rs2);
 *     bonus.setMatchColumn(1); // EMP_ID is the first column
 *     jrs.addRowSet(bonus);
 * </PRE>
 * <P>
 * At this point, <i>jrs is an inside JOIN of the two RowSet objects
 * based on their <code>EMP_ID columns. The application can now browse the
 * combined data as if it were browsing one single <code>RowSet object.
 * Because <i>jrs is itself a RowSet object, an application can
 * navigate or modify it using <code>RowSet methods.
 * <PRE>
 *     jrs.first();
 *     int employeeID = jrs.getInt(1);
 *     String employeeName = jrs.getString(2);
 * </PRE>
 * <P>
 * Note that because the SQL <code>JOIN must be enforced when an application
 * adds a second or subsequent <code>RowSet object, there
 * may be an initial degradation in performance while the <code>JOIN is
 * being performed.
 * <P>
 * The following code fragment adds an additional <code>CachedRowSet object.
 * In this case, the match column (<code>EMP_ID) is set when the
 * <code>CachedRowSet object is added to the JoinRowSet object.
 * <PRE>
 *     ResultSet rs3 = stmt.executeQuery("SELECT * FROM 401K_CONTRIB");
 *     CachedRowSet fourO1k = new CachedRowSetImpl();
 *     four01k.populate(rs3);
 *     jrs.addRowSet(four01k, 1);
 * </PRE>
 * <P>
 * The <code>JoinRowSet object jrs now contains values from all three
 * tables. The data in each row in <i>four01k in which the value for the
 * <code>EMP_ID column matches a value for the EMP_ID column
 * in <i>jrs has been added to jrs.
 *
 * <h3>4.0 JoinRowSet Methods
 * The <code>JoinRowSet interface supplies several methods for adding
 * <code>RowSet objects and for getting information about the
 * <code>JoinRowSet object.
 * <UL>
 *   <LI>Methods for adding one or more RowSet objects

 *       These methods allow an application to add one <code>RowSet object
 *       at a time or to add multiple <code>RowSet objects at one time. In
 *       either case, the methods may specify the match column for each
 *       <code>RowSet object being added.
 *   <LI>Methods for getting information

 *       One method retrieves the <code>RowSet objects in the
 *       <code>JoinRowSet object, and another method retrieves the
 *       <code>RowSet names.  A third method retrieves either the SQL
 *       <code>WHERE clause used behind the scenes to form the
 *       <code>JOIN or a text description of what the WHERE
 *       clause does.
 *   <LI>Methods related to the type of JOIN

 *       One method sets the <code>JOIN type, and five methods find out whether
 *       the <code>JoinRowSet object supports a given type.
 *   <LI>A method to make a separate copy of the JoinRowSet object

 *       This method creates a copy that can be persisted to the data source.
 * </UL>
 *
 */

public interface JoinRowSet extends WebRowSet {

    /**
     * Adds the given <code>RowSet object to this JoinRowSet
     * object. If the <code>RowSet object
     * is the first to be added to this <code>JoinRowSet
     * object, it forms the basis of the <code>JOIN relationship to be
     * established.
     * <P>
     * This method should be used only when the given <code>RowSet
     * object already has a match column that was set with the <code>Joinable
     * method <code>setMatchColumn.
     * <p>
     * Note: A <code>Joinable object is any RowSet object
     * that has implemented the <code>Joinable interface.
     *
     * @param rowset the <code>RowSet object that is to be added to this
     *        <code>JoinRowSet object; it must implement the
     *        <code>Joinable interface and have a match column set
     * @throws SQLException if (1) an empty rowset is added to the to this
     *         <code>JoinRowSet object, (2) a match column has not been
     *         set for <i>rowset, or (3) rowset
     *         violates the active <code>JOIN
     * @see Joinable#setMatchColumn
     */
    public void addRowSet(Joinable rowset) throws SQLException;

    /**
     * Adds the given <code>RowSet object to this JoinRowSet
     * object and sets the designated column as the match column for
     * the <code>RowSet object. If the RowSet object
     * is the first to be added to this <code>JoinRowSet
     * object, it forms the basis of the <code>JOIN relationship to be
     * established.
     * <P>
     * This method should be used when <i>RowSet does not already have a match
     * column set.
     *
     * @param rowset the <code>RowSet object that is to be added to this
     *        <code>JoinRowSet object; it may implement the
     *        <code>Joinable interface
     * @param columnIdx an <code>int that identifies the column to become the
     *         match column
     * @throws SQLException if (1) <i>rowset is an empty rowset or
     *         (2) <i>rowset violates the active JOIN
     * @see Joinable#unsetMatchColumn
     */
    public void addRowSet(RowSet rowset, int columnIdx) throws SQLException;

    /**
     * Adds <i>rowset to this JoinRowSet object and
     * sets the designated column as the match column. If <i>rowset
     * is the first to be added to this <code>JoinRowSet
     * object, it forms the basis for the <code>JOIN relationship to be
     * established.
     * <P>
     * This method should be used when the given <code>RowSet object
     * does not already have a match column.
     *
     * @param rowset the <code>RowSet object that is to be added to this
     *        <code>JoinRowSet object; it may implement the
     *        <code>Joinable interface
     * @param columnName the <code>String object giving the name of the
     *        column to be set as the match column
     * @throws SQLException if (1) <i>rowset is an empty rowset or
     *         (2) the match column for <i>rowset does not satisfy the
     *         conditions of the <code>JOIN
     */
     public void addRowSet(RowSet rowset,
                           String columnName) throws SQLException;

    /**
     * Adds one or more <code>RowSet objects contained in the given
     * array of <code>RowSet objects to this JoinRowSet
     * object and sets the match column for
     * each of the <code>RowSet objects to the match columns
     * in the given array of column indexes. The first element in
     * <i>columnIdx is set as the match column for the first
     * <code>RowSet object in rowset, the second element of
     * <i>columnIdx is set as the match column for the second element
     * in <i>rowset, and so on.
     * <P>
     * The first <code>RowSet object added to this JoinRowSet
     * object forms the basis for the <code>JOIN relationship.
     * <P>
     * This method should be used when the given <code>RowSet object
     * does not already have a match column.
     *
     * @param rowset an array of one or more <code>RowSet objects
     *        to be added to the <code>JOIN; it may implement the
     *        <code>Joinable interface
     * @param columnIdx an array of <code>int values indicating the index(es)
     *        of the columns to be set as the match columns for the <code>RowSet
     *        objects in <i>rowset
     * @throws SQLException if (1) an empty rowset is added to this
     *         <code>JoinRowSet object, (2) a match column is not set
     *         for a <code>RowSet object in rowset, or (3)
     *         a <code>RowSet object being added violates the active
     *         <code>JOIN
     */
    public void addRowSet(RowSet[] rowset,
                          int[] columnIdx) throws SQLException;

    /**
     * Adds one or more <code>RowSet objects contained in the given
     * array of <code>RowSet objects to this JoinRowSet
     * object and sets the match column for
     * each of the <code>RowSet objects to the match columns
     * in the given array of column names. The first element in
     * <i>columnName is set as the match column for the first
     * <code>RowSet object in rowset, the second element of
     * <i>columnName is set as the match column for the second element
     * in <i>rowset, and so on.
     * <P>
     * The first <code>RowSet object added to this JoinRowSet
     * object forms the basis for the <code>JOIN relationship.
     * <P>
     * This method should be used when the given <code>RowSet object(s)
     * does not already have a match column.
     *
     * @param rowset an array of one or more <code>RowSet objects
     *        to be added to the <code>JOIN; it may implement the
     *        <code>Joinable interface
     * @param columnName an array of <code>String values indicating the
     *        names of the columns to be set as the match columns for the
     *        <code>RowSet objects in rowset
     * @throws SQLException if (1) an empty rowset is added to this
     *         <code>JoinRowSet object, (2) a match column is not set
     *         for a <code>RowSet object in rowset, or (3)
     *         a <code>RowSet object being added violates the active
     *         <code>JOIN
     */
    public void addRowSet(RowSet[] rowset,
                          String[] columnName) throws SQLException;

    /**
     * Returns a <code>Collection object containing the
     * <code>RowSet objects that have been added to this
     * <code>JoinRowSet object.
     * This should return the 'n' number of RowSet contained
     * within the <code>JOIN and maintain any updates that have occurred while in
     * this union.
     *
     * @return a <code>Collection object consisting of the
     *        <code>RowSet objects added to this JoinRowSet
     *        object
     * @throws SQLException if an error occurs generating the
     *         <code>Collection object to be returned
     */
    public Collection<?> getRowSets() throws java.sql.SQLException;

    /**
     * Returns a <code>String array containing the names of the
     *         <code>RowSet objects added to this JoinRowSet
     *         object.
     *
     * @return a <code>String array of the names of the
     *         <code>RowSet objects in this JoinRowSet
     *         object
     * @throws SQLException if an error occurs retrieving the names of
     *         the <code>RowSet objects
     * @see CachedRowSet#setTableName
     */
    public String[] getRowSetNames() throws java.sql.SQLException;

    /**
     * Creates a new <code>CachedRowSet object containing the
     * data in this <code>JoinRowSet object, which can be saved
     * to a data source using the <code>SyncProvider object for
     * the <code>CachedRowSet object.
     * <P>
     * If any updates or modifications have been applied to the JoinRowSet
     * the CachedRowSet returned by the method will not be able to persist
     * it's changes back to the originating rows and tables in the
     * in the datasource. The CachedRowSet instance returned should not
     * contain modification data and it should clear all properties of
     * it's originating SQL statement. An application should reset the
     * SQL statement using the <code>RowSet.setCommand method.
     * <p>
     * In order to allow changes to be persisted back to the datasource
     * to the originating tables, the <code>acceptChanges method
     * should be used and called on a JoinRowSet object instance. Implementations
     * can leverage the internal data and update tracking in their
     * implementations to interact with the SyncProvider to persist any
     * changes.
     *
     * @return a CachedRowSet containing the contents of the JoinRowSet
     * @throws SQLException if an error occurs assembling the CachedRowSet
     * object
     * @see javax.sql.RowSet
     * @see javax.sql.rowset.CachedRowSet
     * @see javax.sql.rowset.spi.SyncProvider
     */
    public CachedRowSet toCachedRowSet() throws java.sql.SQLException;

    /**
     * Indicates if CROSS_JOIN is supported by a JoinRowSet
     * implementation
     *
     * @return true if the CROSS_JOIN is supported; false otherwise
     */
    public boolean supportsCrossJoin();

    /**
     * Indicates if INNER_JOIN is supported by a JoinRowSet
     * implementation
     *
     * @return true is the INNER_JOIN is supported; false otherwise
     */
    public boolean supportsInnerJoin();

    /**
     * Indicates if LEFT_OUTER_JOIN is supported by a JoinRowSet
     * implementation
     *
     * @return true is the LEFT_OUTER_JOIN is supported; false otherwise
     */
    public boolean supportsLeftOuterJoin();

    /**
     * Indicates if RIGHT_OUTER_JOIN is supported by a JoinRowSet
     * implementation
     *
     * @return true is the RIGHT_OUTER_JOIN is supported; false otherwise
     */
    public boolean supportsRightOuterJoin();

    /**
     * Indicates if FULL_JOIN is supported by a JoinRowSet
     * implementation
     *
     * @return true is the FULL_JOIN is supported; false otherwise
     */
    public boolean supportsFullJoin();

    /**
     * Allow the application to adjust the type of <code>JOIN imposed
     * on tables contained within the JoinRowSet object instance.
     * Implementations should throw a SQLException if they do
     * not support a given <code>JOIN type.
     *
     * @param joinType the standard JoinRowSet.XXX static field definition
     * of a SQL <code>JOIN to re-configure a JoinRowSet instance on
     * the fly.
     * @throws SQLException if an unsupported <code>JOIN type is set
     * @see #getJoinType
     */
    public void setJoinType(int joinType) throws SQLException;

    /**
     * Return a SQL-like description of the WHERE clause being used
     * in a JoinRowSet object. An implementation can describe
     * the WHERE clause of the SQL <code>JOIN by supplying a SQL
     * strings description of <code>JOIN or provide a textual
     * description to assist applications using a <code>JoinRowSet
     *
     * @return whereClause a textual or SQL description of the logical
     * WHERE clause used in the JoinRowSet instance
     * @throws SQLException if an error occurs in generating a representation
     * of the WHERE clause.
     */
    public String getWhereClause() throws SQLException;

    /**
     * Returns a <code>int describing the set SQL JOIN type
     * governing this JoinRowSet instance. The returned type will be one of
     * standard JoinRowSet types: <code>CROSS_JOIN, INNER_JOIN,
     * <code>LEFT_OUTER_JOIN, RIGHT_OUTER_JOIN or
     * <code>FULL_JOIN.
     *
     * @return joinType one of the standard JoinRowSet static field
     *     definitions of a SQL <code>JOIN. JoinRowSet.INNER_JOIN
     *     is returned as the default <code>JOIN type is no type has been
     *     explicitly set.
     * @throws SQLException if an error occurs determining the SQL <code>JOIN
     *     type supported by the JoinRowSet instance.
     * @see #setJoinType
     */
    public int getJoinType() throws SQLException;

    /**
     * An ANSI-style <code>JOIN providing a cross product of two tables
     */
    public static int CROSS_JOIN = 0;

    /**
     * An ANSI-style <code>JOIN providing a inner join between two tables. Any
     * unmatched rows in either table of the join should be discarded.
     */
    public static int INNER_JOIN = 1;

    /**
     * An ANSI-style <code>JOIN providing a left outer join between two
     * tables. In SQL, this is described where all records should be
     * returned from the left side of the JOIN statement.
     */
    public static int LEFT_OUTER_JOIN = 2;

    /**
     * An ANSI-style <code>JOIN providing a right outer join between
     * two tables. In SQL, this is described where all records from the
     * table on the right side of the JOIN statement even if the table
     * on the left has no matching record.
     */
    public static int RIGHT_OUTER_JOIN = 3;

    /**
     * An ANSI-style <code>JOIN providing a a full JOIN. Specifies that all
     * rows from either table be returned regardless of matching
     * records on the other table.
     */
    public static int FULL_JOIN = 4;


}