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 */ 017package org.apache.logging.log4j.core.appender; 018 019import java.io.IOException; 020import java.io.Writer; 021import java.util.concurrent.TimeUnit; 022 023import org.apache.logging.log4j.core.StringLayout; 024 025/** 026 * Manages a Writer so that it can be shared by multiple Appenders and will 027 * allow appenders to reconfigure without requiring a new writer. 028 */ 029public class WriterManager extends AbstractManager { 030 031 /** 032 * Creates a Manager. 033 * 034 * @param name The name of the stream to manage. 035 * @param data The data to pass to the Manager. 036 * @param factory The factory to use to create the Manager. 037 * @param <T> The type of the WriterManager. 038 * @return A WriterManager. 039 */ 040 public static <T> WriterManager getManager(final String name, final T data, 041 final ManagerFactory<? extends WriterManager, T> factory) { 042 return AbstractManager.getManager(name, factory, data); 043 } 044 protected final StringLayout layout; 045 046 private volatile Writer writer; 047 048 public WriterManager(final Writer writer, final String streamName, final StringLayout layout, 049 final boolean writeHeader) { 050 super(null, streamName); 051 this.writer = writer; 052 this.layout = layout; 053 if (writeHeader && layout != null) { 054 final byte[] header = layout.getHeader(); 055 if (header != null) { 056 try { 057 this.writer.write(new String(header, layout.getCharset())); 058 } catch (final IOException e) { 059 logError("Unable to write header", e); 060 } 061 } 062 } 063 } 064 065 protected synchronized void closeWriter() { 066 final Writer w = writer; // access volatile field only once per method 067 try { 068 w.close(); 069 } catch (final IOException ex) { 070 logError("Unable to close stream", ex); 071 } 072 } 073 074 /** 075 * Flushes any buffers. 076 */ 077 public synchronized void flush() { 078 try { 079 writer.flush(); 080 } catch (final IOException ex) { 081 final String msg = "Error flushing stream " + getName(); 082 throw new AppenderLoggingException(msg, ex); 083 } 084 } 085 086 protected Writer getWriter() { 087 return writer; 088 } 089 090 /** 091 * Returns the status of the stream. 092 * @return true if the stream is open, false if it is not. 093 */ 094 public boolean isOpen() { 095 return getCount() > 0; 096 } 097 098 /** 099 * Default hook to write footer during close. 100 */ 101 @Override 102 public boolean releaseSub(final long timeout, final TimeUnit timeUnit) { 103 writeFooter(); 104 closeWriter(); 105 return true; 106 } 107 108 protected void setWriter(final Writer writer) { 109 final byte[] header = layout.getHeader(); 110 if (header != null) { 111 try { 112 writer.write(new String(header, layout.getCharset())); 113 this.writer = writer; // only update field if writer.write() succeeded 114 } catch (final IOException ioe) { 115 logError("Unable to write header", ioe); 116 } 117 } else { 118 this.writer = writer; 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 str the string to write 126 * @throws AppenderLoggingException if an error occurs. 127 */ 128 protected synchronized void write(final String str) { 129 try { 130 writer.write(str); 131 } catch (final IOException ex) { 132 final String msg = "Error writing to stream " + getName(); 133 throw new AppenderLoggingException(msg, ex); 134 } 135 } 136 137 /** 138 * Writes the footer. 139 */ 140 protected void writeFooter() { 141 if (layout == null) { 142 return; 143 } 144 final byte[] footer = layout.getFooter(); 145 if (footer != null && footer.length > 0) { 146 write(new String(footer, layout.getCharset())); 147 } 148 } 149}