001/** 002 * Licensed to the Apache Software Foundation (ASF) under one or more 003 * contributor license agreements. See the NOTICE file distributed with 004 * this work for additional information regarding copyright ownership. 005 * The ASF licenses this file to You under the Apache License, Version 2.0 006 * (the "License"); you may not use this file except in compliance with 007 * the License. You may obtain a copy of the License at 008 * 009 * http://www.apache.org/licenses/LICENSE-2.0 010 * 011 * Unless required by applicable law or agreed to in writing, software 012 * distributed under the License is distributed on an "AS IS" BASIS, 013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 014 * See the License for the specific language governing permissions and 015 * limitations under the License. 016 */ 017 018package org.apache.activemq.transport.tcp; 019 020import java.io.FilterOutputStream; 021import java.io.IOException; 022import java.io.OutputStream; 023 024/** 025 * An optimized buffered outputstream for Tcp 026 * 027 * 028 */ 029 030public class TcpBufferedOutputStream extends FilterOutputStream implements TimeStampStream { 031 private static final int BUFFER_SIZE = 8192; 032 private byte[] buffer; 033 private int bufferlen; 034 private int count; 035 private volatile long writeTimestamp = -1;//concurrent reads of this value 036 037 038 /** 039 * Constructor 040 * 041 * @param out 042 */ 043 public TcpBufferedOutputStream(OutputStream out) { 044 this(out, BUFFER_SIZE); 045 } 046 047 /** 048 * Creates a new buffered output stream to write data to the specified 049 * underlying output stream with the specified buffer size. 050 * 051 * @param out the underlying output stream. 052 * @param size the buffer size. 053 * @throws IllegalArgumentException if size <= 0. 054 */ 055 public TcpBufferedOutputStream(OutputStream out, int size) { 056 super(out); 057 if (size <= 0) { 058 throw new IllegalArgumentException("Buffer size <= 0"); 059 } 060 buffer = new byte[size]; 061 bufferlen = size; 062 } 063 064 /** 065 * write a byte on to the stream 066 * 067 * @param b - byte to write 068 * @throws IOException 069 */ 070 public void write(int b) throws IOException { 071 if ((bufferlen - count) < 1) { 072 flush(); 073 } 074 buffer[count++] = (byte)b; 075 } 076 077 /** 078 * write a byte array to the stream 079 * 080 * @param b the byte buffer 081 * @param off the offset into the buffer 082 * @param len the length of data to write 083 * @throws IOException 084 */ 085 public void write(byte b[], int off, int len) throws IOException { 086 if (b != null) { 087 if ((bufferlen - count) < len) { 088 flush(); 089 } 090 if (buffer.length >= len) { 091 System.arraycopy(b, off, buffer, count, len); 092 count += len; 093 } else { 094 try { 095 writeTimestamp = System.currentTimeMillis(); 096 out.write(b, off, len); 097 } finally { 098 writeTimestamp = -1; 099 } 100 } 101 } 102 } 103 104 /** 105 * flush the data to the output stream This doesn't call flush on the 106 * underlying outputstream, because Tcp is particularly efficent at doing 107 * this itself .... 108 * 109 * @throws IOException 110 */ 111 public void flush() throws IOException { 112 if (count > 0 && out != null) { 113 try { 114 writeTimestamp = System.currentTimeMillis(); 115 out.write(buffer, 0, count); 116 } finally { 117 writeTimestamp = -1; 118 } 119 count = 0; 120 } 121 } 122 123 /** 124 * close this stream 125 * 126 * @throws IOException 127 */ 128 public void close() throws IOException { 129 super.close(); 130 } 131 132 /* (non-Javadoc) 133 * @see org.apache.activemq.transport.tcp.TimeStampStream#isWriting() 134 */ 135 public boolean isWriting() { 136 return writeTimestamp > 0; 137 } 138 139 /* (non-Javadoc) 140 * @see org.apache.activemq.transport.tcp.TimeStampStream#getWriteTimestamp() 141 */ 142 public long getWriteTimestamp() { 143 return writeTimestamp; 144 } 145 146}