HSQLDB example source code file (ScriptWriterText.java)

This example HSQLDB source code file (ScriptWriterText.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

bytes_insert_into, bytes_term, hsqlexception, hsqlexception, io, ioexception, ioexception, iso8859-1, iso8859-1, object, rowoutputtextlog, rowoutputtextlog, scriptwritertext, string, table

The HSQLDB ScriptWriterText.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.scriptio;

import java.io.IOException;
import java.io.UnsupportedEncodingException;

import org.hsqldb.Database;
import org.hsqldb.HsqlException;
import org.hsqldb.HsqlNameManager;
import org.hsqldb.HsqlNameManager.HsqlName;
import org.hsqldb.NumberSequence;
import org.hsqldb.Session;
import org.hsqldb.Table;
import org.hsqldb.rowio.RowOutputTextLog;

/**
 * Handles all scripting and logging operations. A script consists of two blocks:<p>
 *
 * DDL: SQL statements for table and user definitions
 * DATA: INSERT statements for memory tables
 *
 * This happens as part of the CHECKPOINT and SHUTDOWN COMPACT
 * process. In this case, the
 * DATA block contains the CACHED table data as well.<p>
 *
 * A related use for this class is for saving a current snapshot of the
 * database data to a user-defined file with the SCRIPT command
 *
 * A log consists of SQL statements of different types. Each statement is
 * encoded as ASCII and saved.
 *
 *
 * @author fredt@users
 * @version 1.8.0
 * @since 1.7.2
 */
public class ScriptWriterText extends ScriptWriterBase {

    RowOutputTextLog rowOut;

    // todo - perhaps move this global into a lib utility class
    public final static byte[] BYTES_LINE_SEP;
    static final byte[]        BYTES_COMMIT;
    static final byte[]        BYTES_INSERT_INTO;
    static final byte[]        BYTES_VALUES;
    static final byte[]        BYTES_TERM;
    static final byte[]        BYTES_DELETE_FROM;
    static final byte[]        BYTES_WHERE;
    static final byte[]        BYTES_SEQUENCE;
    static final byte[]        BYTES_SEQUENCE_MID;
    static final byte[]        BYTES_C_ID_INIT;
    static final byte[]        BYTES_C_ID_TERM;
    static final byte[]        BYTES_SCHEMA;

    static {
        String sLineSep = System.getProperty("line.separator", "\n");

        try {
            BYTES_LINE_SEP     = sLineSep.getBytes("ISO8859-1");
            BYTES_COMMIT       = "COMMIT".getBytes("ISO8859-1");
            BYTES_INSERT_INTO  = "INSERT INTO ".getBytes("ISO8859-1");
            BYTES_VALUES       = " VALUES(".getBytes("ISO8859-1");
            BYTES_TERM         = ")".getBytes("ISO8859-1");
            BYTES_DELETE_FROM  = "DELETE FROM ".getBytes("ISO8859-1");
            BYTES_WHERE        = " WHERE ".getBytes("ISO8859-1");
            BYTES_SEQUENCE     = "ALTER SEQUENCE ".getBytes("ISO8859-1");
            BYTES_SEQUENCE_MID = " RESTART WITH ".getBytes("ISO8859-1");
            BYTES_C_ID_INIT    = "/*C".getBytes("ISO8859-1");
            BYTES_C_ID_TERM    = "*/".getBytes("ISO8859-1");
            BYTES_SCHEMA       = "SET SCHEMA ".getBytes("ISO8859-1");
        } catch (UnsupportedEncodingException uuex) {
            throw new java.lang.RuntimeException(uuex.getMessage());
        }
    }

    ScriptWriterText() {}

    public ScriptWriterText(Database db, String file,
                            boolean includeCachedData, boolean newFile,
                            boolean isDump) throws HsqlException {
        super(db, file, includeCachedData, newFile, isDump);
    }

    protected void initBuffers() {
        rowOut = new RowOutputTextLog();
    }

    protected void writeDataTerm() throws IOException {}

    protected void addSessionId(Session session) throws IOException {

        if (session == null) {
            return;
        }

        if (session != currentSession) {
            rowOut.write(BYTES_C_ID_INIT);
            rowOut.writeIntData(session.getId());
            rowOut.write(BYTES_C_ID_TERM);

            currentSession = session;
        }

        if (schemaToLog != session.loggedSchema) {
            writeSchemaStatement(schemaToLog);

            session.loggedSchema = schemaToLog;
        }
    }

    private void writeSchemaStatement(HsqlName schema) {

        rowOut.write(BYTES_SCHEMA);
        rowOut.writeString(schema.statementName);
        rowOut.write(BYTES_LINE_SEP);
    }

    public void writeLogStatement(Session session,
                                  String s) throws IOException, HsqlException {

        schemaToLog = session.currentSchema;
        busyWriting = true;

        rowOut.reset();
        addSessionId(session);
        rowOut.writeString(s);
        rowOut.write(BYTES_LINE_SEP);
        fileStreamOut.write(rowOut.getBuffer(), 0, rowOut.size());

        byteCount   += rowOut.size();
        needsSync   = true;
        busyWriting = false;

        if (forceSync || writeDelay == 0) {
            sync();
        }
    }

    protected void writeRow(Session session, Table table,
                            Object[] data) throws HsqlException, IOException {

        busyWriting = true;

        rowOut.reset();
        ((RowOutputTextLog) rowOut).setMode(RowOutputTextLog.MODE_INSERT);
        addSessionId(session);
        rowOut.write(BYTES_INSERT_INTO);
        rowOut.writeString(table.getName().statementName);
        rowOut.write(BYTES_VALUES);
        rowOut.writeData(data, table);
        rowOut.write(BYTES_TERM);
        rowOut.write(BYTES_LINE_SEP);
        fileStreamOut.write(rowOut.getBuffer(), 0, rowOut.size());

        byteCount   += rowOut.size();
        needsSync   |= session.isAutoCommit();
        busyWriting = false;

        if (forceSync || writeDelay == 0) {
            sync();
        }
    }

    protected void writeTableInit(Table t) throws HsqlException, IOException {

        if (t.isEmpty(currentSession)) {
            return;
        }

        if (schemaToLog == currentSession.loggedSchema) {
            return;
        }

        rowOut.reset();
        writeSchemaStatement(t.getName().schema);
        fileStreamOut.write(rowOut.getBuffer(), 0, rowOut.size());

        currentSession.loggedSchema = schemaToLog;
    }

    public void writeInsertStatement(Session session, Table table,
                                     Object[] data)
                                     throws HsqlException, IOException {

        schemaToLog = table.getName().schema;

        writeRow(session, table, data);
    }

    public void writeDeleteStatement(Session session, Table table,
                                     Object[] data)
                                     throws HsqlException, IOException {

        schemaToLog = table.getName().schema;
        busyWriting = true;

        rowOut.reset();
        ((RowOutputTextLog) rowOut).setMode(RowOutputTextLog.MODE_DELETE);
        addSessionId(session);
        rowOut.write(BYTES_DELETE_FROM);
        rowOut.writeString(table.getName().statementName);
        rowOut.write(BYTES_WHERE);
        rowOut.writeData(table.getColumnCount(), table.getColumnTypes(), data,
                         table.columnList, table.getPrimaryKey());
        rowOut.write(BYTES_LINE_SEP);
        fileStreamOut.write(rowOut.getBuffer(), 0, rowOut.size());

        byteCount   += rowOut.size();
        needsSync   |= session.isAutoCommit();
        busyWriting = false;

        if (forceSync || writeDelay == 0) {
            sync();
        }
    }

    public void writeSequenceStatement(Session session,
                                       NumberSequence seq)
                                       throws HsqlException, IOException {

        schemaToLog = seq.getName().schema;
        busyWriting = true;

        rowOut.reset();
        addSessionId(session);
        rowOut.write(BYTES_SEQUENCE);
        rowOut.writeString(seq.getName().statementName);
        rowOut.write(BYTES_SEQUENCE_MID);
        rowOut.writeLongData(seq.peek());
        rowOut.write(BYTES_LINE_SEP);
        fileStreamOut.write(rowOut.getBuffer(), 0, rowOut.size());

        byteCount   += rowOut.size();
        needsSync   = true;
        busyWriting = false;

        if (forceSync || writeDelay == 0) {
            sync();
        }
    }

    public void writeCommitStatement(Session session)
    throws HsqlException, IOException {

        busyWriting = true;

        rowOut.reset();
        addSessionId(session);
        rowOut.write(BYTES_COMMIT);
        rowOut.write(BYTES_LINE_SEP);
        fileStreamOut.write(rowOut.getBuffer(), 0, rowOut.size());

        byteCount   += rowOut.size();
        needsSync   = true;
        busyWriting = false;

        if (forceSync || writeDelay == 0) {
            sync();
        }
    }

    protected void finalize() {
        sync();
    }
}