org.polymap.core.data.util.ChunkedResponseOutputStream.java Source code

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Here is the source code for org.polymap.core.data.util.ChunkedResponseOutputStream.java

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/* 
 * polymap.org
 * Copyright 2009, Polymap GmbH, and individual contributors as indicated
 * by the @authors tag.
 *
 * This is free software; you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License as
 * published by the Free Software Foundation; either version 2.1 of
 * the License, or (at your option) any later version.
 *
 * This software is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this software; if not, write to the Free
 * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
 * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
 *
 * $Id$
 */

package org.polymap.core.data.util;

import java.io.IOException;
import java.io.OutputStream;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

import org.polymap.core.data.pipeline.ProcessorResponse;
import org.polymap.core.data.pipeline.PipelineExecutor.ProcessorContext;

/**
 * 
 *
 * @author <a href="http://www.polymap.de">Falko Braeutigam</a>
 * @version POLYMAP3 ($Revision$)
 * @since 3.0
 */
public abstract class ChunkedResponseOutputStream extends OutputStream {

    private static final Log log = LogFactory.getLog(ChunkedResponseOutputStream.class);

    public static final int DEFAULT_START_SIZE = 16 * 1024;

    private int bufStartSize = DEFAULT_START_SIZE;

    private byte[] buf;

    private int buflen;

    private ProcessorContext context;

    private int total;

    public ChunkedResponseOutputStream(ProcessorContext context) {
        super();
        this.context = context;
        this.buf = new byte[bufStartSize];
    }

    public void write(int b) throws IOException {
        write(new byte[] { (byte) b }, 0, 1);
    }

    public void write(byte[] b, int off, int len) throws IOException {
        //log.info( "    --->receive: " + len + ", buf: " + buf.length + " ,available: " + (buf.length-buflen) );
        if ((buflen + len) > bufStartSize) {
            flush();
            // buf to small for the received byte array?
            if (len > buf.length) {
                buf = new byte[len];
            }
        }
        System.arraycopy(b, off, buf, buflen, len);
        buflen += len;
    }

    public void flush() throws IOException {
        try {
            byte[] sendBuf = new byte[buflen];
            System.arraycopy(buf, 0, sendBuf, 0, buflen);
            context.sendResponse(createResponse(sendBuf, buflen));
            total += buflen;
            log.debug("    --->data sent: " + buflen + " (total: " + total + ")");
            buflen = 0;
        } catch (Exception e) {
            throw new IOException(e);
        }
    }

    /**
     * Returns to total byte count sent so far.
     */
    public int getTotalSent() {
        return total;
    }

    /**
     * 
     * @param _buf The bytes to send. This array is already copied and can be
     *        used without any side effects.
     * @param _buflen The number of valid bytes in the <code>_buf</code>.
     * @return
     */
    protected abstract ProcessorResponse createResponse(byte[] _buf, int _buflen);

}