content: /**
   * Licensed to the Apache Software Foundation (ASF) under one or more
   * contributor license agreements.  See the NOTICE file distributed with
   * this work for additional information regarding copyright ownership.
   * The ASF licenses this file to You 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.activemq.transport.tcp;
  
  import java.io.FilterOutputStream;
  import java.io.IOException;
  import java.io.OutputStream;
  
  /**
   * An optimized buffered outputstream for Tcp
   * 
   * 
   */
  
  public class TcpBufferedOutputStream extends FilterOutputStream implements TimeStampStream {
      private static final int BUFFER_SIZE = 8192;
      private byte[] buffer;
      private int bufferlen;
      private int count;
      private volatile long writeTimestamp = -1;//concurrent reads of this value
      
  
      /**
       * Constructor
       * 
       * @param out
       */
      public TcpBufferedOutputStream(OutputStream out) {
          this(out, BUFFER_SIZE);
      }
  
      /**
       * Creates a new buffered output stream to write data to the specified
       * underlying output stream with the specified buffer size.
       * 
       * @param out the underlying output stream.
       * @param size the buffer size.
       * @throws IllegalArgumentException if size <= 0.
       */
      public TcpBufferedOutputStream(OutputStream out, int size) {
          super(out);
          if (size <= 0) {
              throw new IllegalArgumentException("Buffer size <= 0");
          }
          buffer = new byte[size];
          bufferlen = size;
      }
  
      /**
       * write a byte on to the stream
       * 
       * @param b - byte to write
       * @throws IOException
       */
      public void write(int b) throws IOException {
          if ((bufferlen - count) < 1) {
              flush();
          }
          buffer[count++] = (byte)b;
      }
  
      /**
       * write a byte array to the stream
       * 
       * @param b the byte buffer
       * @param off the offset into the buffer
       * @param len the length of data to write
       * @throws IOException
       */
      public void write(byte b[], int off, int len) throws IOException {
          if (b != null) {
              if ((bufferlen - count) < len) {
                  flush();
              }
              if (buffer.length >= len) {
                  System.arraycopy(b, off, buffer, count, len);
                  count += len;
              } else {
                  try {
                      writeTimestamp = System.currentTimeMillis();
                      out.write(b, off, len);
                  } finally {
                      writeTimestamp = -1;
                  }
              }
          }
      }
  
      /**
       * flush the data to the output stream This doesn't call flush on the
       * underlying outputstream, because Tcp is particularly efficent at doing
       * this itself ....
       * 
       * @throws IOException
       */
      public void flush() throws IOException {
          if (count > 0 && out != null) {
              try {
                  writeTimestamp = System.currentTimeMillis();
                  out.write(buffer, 0, count);
              } finally {
              	writeTimestamp = -1;
              }
              count = 0;
          }
      }
  
      /**
       * close this stream
       * 
       * @throws IOException
       */
      public void close() throws IOException {
          super.close();
      }
  
      /* (non-Javadoc)
       * @see org.apache.activemq.transport.tcp.TimeStampStream#isWriting()
       */
      public boolean isWriting() {
          return writeTimestamp > 0;
      }
      
      /* (non-Javadoc)
       * @see org.apache.activemq.transport.tcp.TimeStampStream#getWriteTimestamp()
       */
      public long getWriteTimestamp() {
      	return writeTimestamp;
      }
  
  }
  