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 java.io.Serializable; 020 import java.util.concurrent.locks.Lock; 021 import java.util.concurrent.locks.ReadWriteLock; 022 import java.util.concurrent.locks.ReentrantReadWriteLock; 023 024 import org.apache.logging.log4j.core.Filter; 025 import org.apache.logging.log4j.core.Layout; 026 import org.apache.logging.log4j.core.LogEvent; 027 028 /** 029 * Appends log events as bytes to a byte output stream. The stream encoding is defined in the layout. 030 * 031 * @param <M> The kind of {@link OutputStreamManager} under management 032 */ 033 public abstract class AbstractOutputStreamAppender<M extends OutputStreamManager> extends AbstractAppender { 034 035 /** 036 * Immediate flush means that the underlying writer or output stream 037 * will be flushed at the end of each append operation. Immediate 038 * flush is slower but ensures that each append request is actually 039 * written. If <code>immediateFlush</code> is set to 040 * {@code false}, then there is a good chance that the last few 041 * logs events are not actually written to persistent media if and 042 * when the application crashes. 043 */ 044 protected final boolean immediateFlush; 045 046 private final M manager; 047 048 private final ReadWriteLock rwLock = new ReentrantReadWriteLock(); 049 private final Lock readLock = rwLock.readLock(); 050 051 /** 052 * Instantiate a WriterAppender and set the output destination to a 053 * new {@link java.io.OutputStreamWriter} initialized with <code>os</code> 054 * as its {@link java.io.OutputStream}. 055 * @param name The name of the Appender. 056 * @param layout The layout to format the message. 057 * @param manager The OutputStreamManager. 058 */ 059 protected AbstractOutputStreamAppender(final String name, final Layout<? extends Serializable> layout, final Filter filter, 060 final boolean ignoreExceptions, final boolean immediateFlush, 061 final M manager) { 062 super(name, filter, layout, ignoreExceptions); 063 this.manager = manager; 064 this.immediateFlush = immediateFlush; 065 } 066 067 /** 068 * Gets the manager. 069 * 070 * @return the manager. 071 */ 072 public M getManager() { 073 return manager; 074 } 075 076 @Override 077 public void start() { 078 if (getLayout() == null) { 079 LOGGER.error("No layout set for the appender named [" + getName() + "]."); 080 } 081 if (manager == null) { 082 LOGGER.error("No OutputStreamManager set for the appender named [" + getName() + "]."); 083 } 084 super.start(); 085 } 086 087 @Override 088 public void stop() { 089 super.stop(); 090 manager.release(); 091 } 092 093 /** 094 * Actual writing occurs here. 095 * <p/> 096 * <p>Most subclasses of <code>AbstractOutputStreamAppender</code> will need to 097 * override this method. 098 * @param event The LogEvent. 099 */ 100 @Override 101 public void append(final LogEvent event) { 102 readLock.lock(); 103 try { 104 final byte[] bytes = getLayout().toByteArray(event); 105 if (bytes.length > 0) { 106 manager.write(bytes); 107 if (this.immediateFlush || event.isEndOfBatch()) { 108 manager.flush(); 109 } 110 } 111 } catch (final AppenderLoggingException ex) { 112 error("Unable to write to stream " + manager.getName() + " for appender " + getName()); 113 throw ex; 114 } finally { 115 readLock.unlock(); 116 } 117 } 118 }