RAFileHybrid.java

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package org.hsqldb.persist;

import java.io.IOException;

import org.hsqldb.Database;

/**
 * Mixed NIO / non-NIO version of ScaledRAFile.
 * This class is used only for storing a CACHED
 * TABLE .data file and cannot be used for TEXT TABLE source files.
 *
 * Due to various issues with java.nio classes, this class will use a mapped
 * channel of fixed size. After reaching this size, the file and channel are
 * closed and a new one opened, up to the maximum size.
 *
 * @author Fred Toussi (fredt@users dot sourceforge.net)
 * @version 2.3.3
 * @since 1.7.2
 */
public final class RAFileHybrid implements RandomAccessInterface {

    final Database        database;
    final String          fileName;
    final boolean         isReadOnly;
    boolean               preNio;
    boolean               isNio;
    long                  initialMaxLength = RAFileNIO.largeBufferSize / 2;
    RandomAccessInterface store;

    public RAFileHybrid(
            Database database,
            String name,
            boolean readOnly)
            throws IOException {

        this.database   = database;
        this.fileName   = name;
        this.isReadOnly = readOnly;

        long         fileLength;
        java.io.File fi = new java.io.File(name);

        fileLength = fi.length();

        newStore(fileLength);
    }

    public long length() throws IOException {
        return store.length();
    }

    public void seek(long position) throws IOException {
        store.seek(position);
    }

    public long getFilePointer() throws IOException {
        return store.getFilePointer();
    }

    public int read() throws IOException {
        return store.read();
    }

    public void read(byte[] b, int offset, int length) throws IOException {
        store.read(b, offset, length);
    }

    public void write(byte[] b, int offset, int length) throws IOException {
        store.write(b, offset, length);
    }

    public int readInt() throws IOException {
        return store.readInt();
    }

    public void writeInt(int i) throws IOException {
        store.writeInt(i);
    }

    public long readLong() throws IOException {
        return store.readLong();
    }

    public void writeLong(long i) throws IOException {
        store.writeLong(i);
    }

    public void close() throws IOException {
        store.close();
    }

    public boolean isReadOnly() {
        return store.isReadOnly();
    }

    public boolean ensureLength(long newLength) {

        if (newLength <= initialMaxLength) {
            return store.ensureLength(newLength);
        } else if (preNio) {
            try {
                newStore(newLength);
            } catch (IOException e) {}
        }

        if (store.ensureLength(newLength)) {
            return true;
        } else if (isNio) {
            try {
                newStore(newLength);
            } catch (IOException e) {}
        }

        return store.ensureLength(newLength);
    }

    public boolean setLength(long newLength) {
        return store.setLength(newLength);
    }

    public Database getDatabase() {
        return null;
    }

    public void synch() {
        store.synch();
    }

    void newStore(long requiredPosition) throws IOException {

        long currentPosition = 0;

        if (store == null) {
            preNio = requiredPosition <= database.logger.propNioMaxSize;
        } else {
            currentPosition = store.getFilePointer();

            store.synch();
            store.close();
        }

        if (preNio && initialMaxLength <= requiredPosition) {
            try {
                store = new RAFileNIO(
                    database.logger,
                    fileName,
                    isReadOnly,
                    requiredPosition,
                    database.logger.propNioMaxSize);

                store.seek(currentPosition);

                preNio = false;
                isNio  = true;

                return;
            } catch (Throwable e) {
                preNio = false;

                // log event
            }
        }

        isNio = false;
        store = new RAFile(database.logger, fileName, isReadOnly, true, false);

        store.seek(currentPosition);
    }
}