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 package org.apache.logging.log4j.core.appender; 018 019 import org.apache.logging.log4j.core.Layout; 020 021 import java.io.IOException; 022 import java.io.OutputStream; 023 024 /** 025 * Manage an OutputStream so that it can be shared by multiple Appenders and will 026 * allow appenders to reconfigure without requiring a new stream. 027 */ 028 public class OutputStreamManager extends AbstractManager { 029 030 private volatile OutputStream os; 031 032 private final byte[] footer; 033 private final byte[] header; 034 035 protected OutputStreamManager(final OutputStream os, final String streamName, final Layout layout) { 036 super(streamName); 037 this.os = os; 038 if (layout != null) { 039 this.footer = layout.getFooter(); 040 this.header = layout.getHeader(); 041 if (this.header != null) { 042 try { 043 this.os.write(header, 0, header.length); 044 } catch (final IOException ioe) { 045 LOGGER.error("Unable to write header", ioe); 046 } 047 } 048 } else { 049 this.footer = null; 050 this.header = null; 051 } 052 } 053 054 /** 055 * Create a Manager. 056 * 057 * @param name The name of the stream to manage. 058 * @param data The data to pass to the Manager. 059 * @param factory The factory to use to create the Manager. 060 * @param <T> The type of the OutputStreamManager. 061 * @return An OutputStreamManager. 062 */ 063 public static <T> OutputStreamManager getManager(final String name, final T data, 064 final ManagerFactory<? extends OutputStreamManager, T> factory) { 065 return AbstractManager.getManager(name, factory, data); 066 } 067 068 /** 069 * Default hook to write footer during close. 070 */ 071 @Override 072 public void releaseSub() { 073 if (footer != null) { 074 write(footer); 075 } 076 close(); 077 } 078 079 /** 080 * Returns the status of the stream. 081 * @return true if the stream is open, false if it is not. 082 */ 083 public boolean isOpen() { 084 return getCount() > 0; 085 } 086 087 protected OutputStream getOutputStream() { 088 return os; 089 } 090 091 protected void setOutputStream(final OutputStream os) { 092 if (header != null) { 093 try { 094 os.write(header, 0, header.length); 095 this.os = os; // only update field if os.write() succeeded 096 } catch (final IOException ioe) { 097 LOGGER.error("Unable to write header", ioe); 098 } 099 } else { 100 this.os = os; 101 } 102 } 103 104 /** 105 * Some output streams synchronize writes while others do not. Synchronizing here insures that 106 * log events won't be intertwined. 107 * @param bytes The serialized Log event. 108 * @param offset The offset into the byte array. 109 * @param length The number of bytes to write. 110 * @throws AppenderRuntimeException if an error occurs. 111 */ 112 protected synchronized void write(final byte[] bytes, final int offset, final int length) { 113 //System.out.println("write " + count); 114 try { 115 os.write(bytes, offset, length); 116 } catch (final IOException ex) { 117 final String msg = "Error writing to stream " + getName(); 118 throw new AppenderRuntimeException(msg, ex); 119 } 120 } 121 122 /** 123 * Some output streams synchronize writes while others do not. Synchronizing here insures that 124 * log events won't be intertwined. 125 * @param bytes The serialized Log event. 126 * @throws AppenderRuntimeException if an error occurs. 127 */ 128 protected void write(final byte[] bytes) { 129 write(bytes, 0, bytes.length); 130 } 131 132 protected void close() { 133 OutputStream stream = os; // access volatile field only once per method 134 if (stream == System.out || stream == System.err) { 135 return; 136 } 137 try { 138 stream.close(); 139 } catch (final IOException ex) { 140 LOGGER.error("Unable to close stream " + getName() + ". " + ex); 141 } 142 } 143 144 /** 145 * Flush any buffers. 146 */ 147 public void flush() { 148 try { 149 os.flush(); 150 } catch (final IOException ex) { 151 final String msg = "Error flushing stream " + getName(); 152 throw new AppenderRuntimeException(msg, ex); 153 } 154 } 155 }