SerialOutput.java

/*-
 * See the file LICENSE for redistribution information.
 *
 * Copyright (c) 2000-2005
 *      Sleepycat Software.  All rights reserved.
 *
 * $Id: SerialOutput.java,v 12.2 2005/08/01 20:25:07 mark Exp $
 */

package com.sleepycat.bind.serial;

import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.ObjectOutputStream;
import java.io.ObjectStreamClass;
import java.io.ObjectStreamConstants;
import java.io.OutputStream;

import com.sleepycat.db.DatabaseException;
import com.sleepycat.util.RuntimeExceptionWrapper;

public class SerialOutput extends ObjectOutputStream {

    /* 
     * Serialization version constants. Instead of hardcoding these we get them
     * by creating a SerialOutput, which itself guarantees that we'll always
     * use a PROTOCOL_VERSION_2 header.
     */
    private final static byte[] STREAM_HEADER;
    static {
        ByteArrayOutputStream baos = new ByteArrayOutputStream();
        try {
            new SerialOutput(baos, null);
        } catch (IOException e) {
            throw new RuntimeExceptionWrapper(e);
        }
        STREAM_HEADER = baos.toByteArray();
    }

    private ClassCatalog classCatalog;

    public SerialOutput(OutputStream out, ClassCatalog classCatalog)
        throws IOException {

        super(out);
        this.classCatalog = classCatalog;

        /* guarantee that we'll always use the same serialization format */

        useProtocolVersion(ObjectStreamConstants.PROTOCOL_VERSION_2);
    }

    // javadoc is inherited
    protected void writeClassDescriptor(ObjectStreamClass classdesc)
        throws IOException {

        try {
            byte[] id = classCatalog.getClassID(classdesc);
            writeByte(id.length);
            write(id);
        } catch (DatabaseException e) {
            /*
             * Do not throw IOException from here since ObjectOutputStream
             * will write the exception to the stream, which causes another
             * call here, etc.
             */
            throw new RuntimeExceptionWrapper(e);
        } catch (ClassNotFoundException e) {
            throw new RuntimeExceptionWrapper(e);
        }
    }

    public static byte[] getStreamHeader() {

        return STREAM_HEADER;
    }
}

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