DataFileCacheSession.java

/* Copyright (c) 2001-2011, The HSQL Development Group
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package org.hsqldb.persist;

import org.hsqldb.Database;
import org.hsqldb.Row;
import org.hsqldb.error.Error;
import org.hsqldb.error.ErrorCode;
import org.hsqldb.lib.FileUtil;
import org.hsqldb.lib.Iterator;

/**
 * A file-based row store for temporary CACHED table persistence.<p>
 *
 * @author Fred Toussi (fredt@users dot sourceforge.net)
 * @version 2.3.0
 * @since 1.9.0
 */
public class DataFileCacheSession extends DataFileCache {

    public DataFileCacheSession(Database db, String baseFileName) {

        super(db, baseFileName);

        logEvents = false;
    }

    /**
     * Initial external parameters are set here. The size if fixed.
     */
    protected void initParams(Database database, String baseFileName,
                              boolean defrag) {

        this.dataFileName = baseFileName + ".data.tmp";
        this.database     = database;
        fa                = FileUtil.getFileUtil();
        dataFileScale     = 64;
        cachedRowPadding  = dataFileScale;
        initialFreePos    = dataFileScale;
        maxCacheRows      = 2048;
        maxCacheBytes     = maxCacheRows * 1024;
        maxDataFileSize   = (long) Integer.MAX_VALUE * dataFileScale;
    }

    /**
     * Opens the *.data file for this cache.
     */
    public void open(boolean readonly) {

        try {
            dataFile = new RAFile(database, dataFileName, false, false, false);
            fileFreePosition = initialFreePos;

            initBuffers();

            spaceManager = new DataSpaceManagerSimple(this);
        } catch (Throwable t) {
            database.logger.logWarningEvent("Failed to open Session RA file",
                                            t);
            release();

            throw Error.error(t, ErrorCode.FILE_IO_ERROR,
                              ErrorCode.M_DataFileCache_open, new Object[] {
                t.toString(), dataFileName
            });
        }
    }

    protected void setFileModified() {}

    /**
     *  Parameter write is always false. The backing file is simply closed and
     *  deleted.
     */
    public void close() {

        writeLock.lock();

        try {
            clear();

            if (dataFile != null) {
                dataFile.close();

                dataFile = null;

                fa.removeElement(dataFileName);
            }
        } catch (Throwable t) {
            database.logger.logWarningEvent("Failed to close Session RA file",
                                            t);

            throw Error.error(t, ErrorCode.FILE_IO_ERROR,
                              ErrorCode.M_DataFileCache_close, new Object[] {
                t.toString(), dataFileName
            });
        } finally {
            writeLock.unlock();
        }
    }

    public void adjustStoreCount(int adjust) {

        writeLock.lock();

        try {
            storeCount += adjust;

            if (storeCount == 0) {
                clear();
            }
        } finally {
            writeLock.unlock();
        }
    }

    protected void clear() {

        Iterator it = cache.getIterator();

        while (it.hasNext()) {
            Row row = (Row) it.next();

            row.setInMemory(false);
            row.destroy();
        }

        cache.clear();

        fileStartFreePosition = fileFreePosition = initialFreePos;

        initBuffers();
    }
}