byteswrittenresetoutputstream.java

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/***********************************************************************
 * Copyright (c) 2000-2004 The Apache Software Foundation.             *
 * All rights reserved.                                                *
 * ------------------------------------------------------------------- *
 * Licensed under the Apache License, Version 2.0 (the "License"); you *
 * may not use this file except in compliance with the License. You    *
 * may obtain a copy of the License at:                                *
 *                                                                     *
 *     http://www.apache.org/licenses/LICENSE-2.0                      *
 *                                                                     *
 * Unless required by applicable law or agreed to in writing, software *
 * distributed under the License is distributed on an "AS IS" BASIS,   *
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or     *
 * implied.  See the License for the specific language governing       *
 * permissions and limitations under the License.                      *
 ***********************************************************************/


package org.apache.james.util.watchdog;

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

/**
 * This will reset the Watchdog each time a certain amount of data has
 * been transferred.  This allows us to keep the timeout settings low, while
 * not timing out during large data transfers.
 */
public class BytesWrittenResetOutputStream extends OutputStream {

    /**
     * The output stream wrapped by this method
     */
    OutputStream out = null;

    /**
     * The Watchdog to be reset every lengthReset bytes
     */
    private Watchdog watchdog;

    /**
     * The number of bytes that need to be written before the counter is reset.
     */
    int lengthReset = 0;

    /**
     * The number of bytes written since the counter was last reset
     */
    int writtenCounter = 0;

    public BytesWrittenResetOutputStream(OutputStream out,
                                         Watchdog watchdog,
                                         int lengthReset) {
        this.out = out;
        this.watchdog = watchdog;
        this.lengthReset = lengthReset;

        writtenCounter = 0;
    }

    /**
     * Write an array of bytes to the stream
     *
     * @param b the array of bytes to write to the stream
     * @param off the index in the array where we start writing
     * @param len the number of bytes of the array to write
     *
     * @throws IOException if an exception is encountered when writing
     */
    public void write(byte[] b, int off, int len) throws IOException {
        out.write(b, off, len);
        writtenCounter += len;

        if (writtenCounter > lengthReset) {
            writtenCounter = 0;
            watchdog.reset();
        }
    }

    /**
     * Write a byte to the stream
     *
     * @param b the byte to write to the stream
     *
     * @throws IOException if an exception is encountered when writing
     */
    public void write(int b) throws IOException {
        out.write(b);
        writtenCounter++;

        if (writtenCounter > lengthReset) {
            writtenCounter = 0;
            watchdog.reset();
        }
    }

    /**
     * Flush the stream
     *
     * @throws IOException if an exception is encountered when flushing
     */
    public void flush() throws IOException {
        out.flush();
    }

    /**
     * Close the stream
     *
     * @throws IOException if an exception is encountered when closing
     */
    public void close() throws IOException {
        out.close();
    }
}