Quadcap Embeddable Database

com/quadcap/sql/file/Log2.java

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package com.quadcap.sql.file;

/* Copyright 1999 - 2003 Quadcap Software.  All rights reserved.
 *
 * This software is distributed under the Quadcap Free Software License.
 * This software may be used or modified for any purpose, personal or
 * commercial.  Open Source redistributions are permitted.  Commercial
 * redistribution of larger works derived from, or works which bundle
 * this software requires a "Commercial Redistribution License"; see
 * http://www.quadcap.com/purchase.
 *
 * Redistributions qualify as "Open Source" under  one of the following terms:
 *   
 *    Redistributions are made at no charge beyond the reasonable cost of
 *    materials and delivery.
 *
 *    Redistributions are accompanied by a copy of the Source Code or by an
 *    irrevocable offer to provide a copy of the Source Code for up to three
 *    years at the cost of materials and delivery.  Such redistributions
 *    must allow further use, modification, and redistribution of the Source
 *    Code under substantially the same terms as this license.
 *
 * Redistributions of source code must retain the copyright notices as they
 * appear in each source code file, these license terms, and the
 * disclaimer/limitation of liability set forth as paragraph 6 below.
 *
 * Redistributions in binary form must reproduce this Copyright Notice,
 * these license terms, and the disclaimer/limitation of liability set
 * forth as paragraph 6 below, in the documentation and/or other materials
 * provided with the distribution.
 *
 * The Software is provided on an "AS IS" basis.  No warranty is
 * provided that the Software is free of defects, or fit for a
 * particular purpose.  
 *
 * Limitation of Liability. Quadcap Software shall not be liable
 * for any damages suffered by the Licensee or any third party resulting
 * from use of the Software.
 */

import java.io.File;
import java.io.IOException;

import java.util.Properties;

import com.quadcap.sql.lock.Transaction;

import com.quadcap.util.Debug;


/**
 * Interface to logging subsystem.
 *
 * @author Stan Bailes
 */
public class Log2 extends Log1 {

    /**
     * Initialize the logging subsystem
     */
    public void init(Datafile db, boolean create, Properties props)
        throws IOException
    {
        super.init(db, create, props);
    }

    /**
     * Start the logging subsystem
     */
    public void start() {}

    /**
     * Add a transaction's log record to the end of the open log file
     */
    public void addEntry(LogEntry entry) throws IOException {
        synchronized (fileLock) {
            super.reallyAddEntry(entry);
        }
    }

    /**
     * XXX why public?
     */
    public void reallyAddEntry(LogEntry entry) throws IOException {
        synchronized (fileLock) {
            super.reallyAddEntry(entry);
        }
    }
    
    /**
     * Flush and close the log file.
     */
    public void close() throws IOException {
        synchronized (fileLock) {
            logger.close();
            reallyClose();
        }
    }
        
    
    /**
     * Flush all log records to disk. 
     */
    public void flushLog() throws IOException {
        synchronized (fileLock) {
            reallyFlush();
            maybeCheckpoint();
        }
    }

    /**
     * Perform a checkpoint operation.
     */
    public void checkpoint() throws IOException {
        synchronized (fileLock) {
            reallyCheckpoint();
        }
    }

    /**
     * Wait for all queued ops to be processed by the log sync thread
     */
    public void sync() throws IOException {
        synchronized (fileLock) {
            // we're synchronous, remember?
        }
    }

    /**
     * Transaction rollback.
     */
    public void rollbackTransaction(Transaction trans) throws IOException {
        try {
            synchronized (fileLock) {
                reallyRollbackTransaction(trans);
            }
        } catch (Exception e) {
            throw new DatafileException(e);
        }
    }
        
    /**
     * Statement rollback.
     */
    public void rollbackStatement(Transaction trans, int stmtId)
        throws IOException
    {
        try {
            synchronized (fileLock) {
                reallyRollbackStatement(trans, stmtId);
            }
        } catch (Exception e) {
            throw new DatafileException(e);
        }
    }

    /**
     * Restart from a previous state
     */
    public void restart() throws Exception {
        synchronized (fileLock) {
            reallyRestart();
        }
    }
}