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HSQLDB example source code file (TextTable.java)

This example HSQLDB source code file (TextTable.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

Java - HSQLDB tags/keywords

cachedrow, hsqlexception, hsqlexception, integer, object, string, string, table, textcache, textcache, texttable, texttable

The HSQLDB TextTable.java source code

/* Copyright (c) 2001-2008, The HSQL Development Group
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * Redistributions of source code must retain the above copyright notice, this
 * list of conditions and the following disclaimer.
 *
 * Redistributions in binary form must reproduce the above copyright notice,
 * this list of conditions and the following disclaimer in the documentation
 * and/or other materials provided with the distribution.
 *
 * Neither the name of the HSQL Development Group nor the names of its
 * contributors may be used to endorse or promote products derived from this
 * software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL HSQL DEVELOPMENT GROUP, HSQLDB.ORG,
 * OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */


package org.hsqldb;

import org.hsqldb.lib.FileUtil;
import org.hsqldb.lib.StringConverter;
import org.hsqldb.persist.TextCache;

// tony_lai@users 20020820 - patch 595099 - user define PK name

/**
 * Subclass of Table to handle TEXT data source. <p>
 *
 * Extends Table to provide the notion of an SQL base table object whose
 * data is read from and written to a text format data file.
 *
 * @author sqlbob@users (RMP)
 * @version    1.8.0
 */
class TextTable extends org.hsqldb.Table {

    private String  dataSource  = "";
    private boolean isReversed  = false;
    private boolean isConnected = false;

    /**
     *  Constructs a new TextTable from the given arguments.
     *
     * @param  db the owning database
     * @param  name the table's HsqlName
     * @param  type (normal or temp text table)
     * @param  sessionid the id of the owning session (for temp table)
     * @exception  HsqlException  Description of the Exception
     */
    TextTable(Database db, HsqlNameManager.HsqlName name,
              int type) throws HsqlException {
        super(db, name, type);
    }

    /**
     * common handling for all errors during <code>connect
     */
    private void onConnectError(Session session) {

        if (cache != null) {
            try {
                cache.close(false);
            } catch (HsqlException ex) {}
        }

        cache = null;

        clearAllRows(session);
    }

    public boolean isConnected() {
        return isConnected;
    }

    /**
     * connects to the data source
     */
    public void connect(Session session) throws HsqlException {
        connect(session, isReadOnly);
    }

    /**
     * connects to the data source
     */
    private void connect(Session session,
                         boolean withReadOnlyData) throws HsqlException {

        // Open new cache:
        if ((dataSource.length() == 0) || isConnected) {

            // nothing to do
            return;
        }

        try {
            cache = database.logger.openTextCache(this, dataSource,
                                                  withReadOnlyData,
                                                  isReversed);

            // read and insert all the rows from the source file
            CachedRow row     = null;
            int       nextpos = 0;

            if (((TextCache) cache).ignoreFirst) {
                nextpos += ((TextCache) cache).readHeaderLine();
            }

            while (true) {
                row = (CachedRow) rowStore.get(nextpos);

                if (row == null) {
                    break;
                }

                nextpos = row.getPos() + row.getStorageSize();

                row.setNewNodes();
                insertFromTextSource(row);
            }
        } catch (HsqlException e) {
            int linenumber = cache == null ? 0
                                           : ((TextCache) cache)
                                               .getLineNumber();

            onConnectError(session);

            // everything is in order here.
            // At this point table should either have a valid (old) data
            // source and cache or have an empty source and null cache.
            throw Trace.error(Trace.TEXT_FILE, new Object[] {
                new Integer(linenumber), e.getMessage()
            });
        } catch (java.lang.RuntimeException t) {
            int linenumber = cache == null ? 0
                                           : ((TextCache) cache)
                                               .getLineNumber();

            onConnectError(session);

            throw Trace.error(Trace.TEXT_FILE, new Object[] {
                new Integer(linenumber),
                t.getClass().getName() + ": " + t.getMessage()
            });
        }

        isConnected = true;

        setIsReadOnly(withReadOnlyData);
    }

    /**
     * disconnects from the data source
     */
    public void disconnect(Session session) throws HsqlException {

        // Close old cache:
        database.logger.closeTextCache(this);

        cache = null;

        clearAllRows(session);

        isConnected = false;
    }

    /**
     * This method does some of the work involved with managing the creation
     * and openning of the cache, the rest is done in Log.java and
     * TextCache.java.
     *
     * Better clarification of the role of the methods is needed.
     */
    private void openCache(Session session, String dataSourceNew,
                           boolean isReversedNew,
                           boolean isReadOnlyNew) throws HsqlException {

        if (dataSourceNew == null) {
            dataSourceNew = "";
        }

        disconnect(session);

        dataSource = dataSourceNew;
        isReversed = (isReversedNew && dataSource.length() > 0);

        connect(session, isReadOnlyNew);
    }

    /**
     * High level command to assign a data source to the table definition.
     * Reassigns only if the data source or direction has changed.
     */
    protected void setDataSource(Session session, String dataSourceNew,
                                 boolean isReversedNew,
                                 boolean newFile) throws HsqlException {

        if (getTableType() == Table.TEMP_TEXT_TABLE) {
            ;
        } else {
            session.checkAdmin();
        }

        dataSourceNew = dataSourceNew.trim();

        if (newFile && FileUtil.getDefaultInstance().exists(dataSourceNew)) {
            throw Trace.error(Trace.TEXT_SOURCE_EXISTS, dataSourceNew);
        }

        //-- Open if descending, direction changed, file changed, or not connected currently
        if (isReversedNew || (isReversedNew != isReversed)
                || !dataSource.equals(dataSourceNew) || !isConnected) {
            openCache(session, dataSourceNew, isReversedNew, isReadOnly);
        }

        if (isReversed) {
            setIsReadOnly(true);
        }
    }

    protected String getDataSource() {
        return dataSource;
    }

    protected boolean isDescDataSource() {
        return isReversed;
    }

    public void setHeader(String header) throws HsqlException {

        if (cache != null && ((TextCache) cache).ignoreFirst) {
            ((TextCache) cache).setHeader(header);

            return;
        }

        throw Trace.error(Trace.TEXT_TABLE_HEADER);
    }

    public String getHeader() {

        String header = cache == null ? null
                                      : ((TextCache) cache).getHeader();

        return header == null ? null
                              : StringConverter.toQuotedString(header, '\"',
                              true);
    }

    /**
     * Used by INSERT, DELETE, UPDATE operations. This class will return
     * a more appropriate message when there is no data source.
     */
    void checkDataReadOnly() throws HsqlException {

        if (dataSource.length() == 0) {
            throw Trace.error(Trace.UNKNOWN_DATA_SOURCE);
        }

        if (isDataReadOnly()) {
            throw Trace.error(Trace.DATA_IS_READONLY);
        }
    }

    public boolean isDataReadOnly() {
        return !isConnected() || super.isDataReadOnly();
    }

    void setDataReadOnly(boolean value) throws HsqlException {

        if (isReversed && value == false) {
            throw Trace.error(Trace.DATA_IS_READONLY);
        }

        openCache(null, dataSource, isReversed, value);
        setIsReadOnly(value);
    }

    boolean isIndexCached() {
        return false;
    }

    protected Table duplicate() throws HsqlException {
        return new TextTable(database, tableName, getTableType());
    }

    void drop() throws HsqlException {
        openCache(null, "", false, false);
    }

    void setIndexRoots(String s) throws HsqlException {

        // do nothing
    }
}

Other HSQLDB examples (source code examples)

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