1 | /*
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2 | * Licensed to the Apache Software Foundation (ASF) under one or more
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3 | * contributor license agreements. See the NOTICE file distributed with
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4 | * this work for additional information regarding copyright ownership.
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5 | * The ASF licenses this file to You under the Apache License, Version 2.0
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6 | * (the "License"); you may not use this file except in compliance with
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7 | * the License. You may obtain a copy of the License at
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8 | *
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9 | * http://www.apache.org/licenses/LICENSE-2.0
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10 | *
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11 | * Unless required by applicable law or agreed to in writing, software
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12 | * distributed under the License is distributed on an "AS IS" BASIS,
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13 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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14 | * See the License for the specific language governing permissions and
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15 | * limitations under the License.
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16 | */
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17 |
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18 | #ifndef _LOG4CXX_WRITER_APPENDER_H
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19 | #define _LOG4CXX_WRITER_APPENDER_H
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20 |
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21 | #if defined(_MSC_VER)
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22 | #pragma warning ( push )
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23 | #pragma warning ( disable: 4231 4251 4275 4786 )
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24 | #endif
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25 |
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26 | #include <log4cxx/appenderskeleton.h>
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27 | #include <log4cxx/helpers/outputstreamwriter.h>
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28 |
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29 | namespace log4cxx
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30 | {
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31 |
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32 | namespace helpers {
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33 | class Transcoder;
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34 | }
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35 |
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36 | /**
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37 | WriterAppender appends log events to a standard output stream
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38 | */
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39 | class LOG4CXX_EXPORT WriterAppender : public AppenderSkeleton
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40 | {
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41 | private:
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42 | /**
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43 | Immediate flush means that the underlying writer or output stream
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44 | will be flushed at the end of each append operation. Immediate
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45 | flush is slower but ensures that each append request is actually
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46 | written. If <code>immediateFlush</code> is set to
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47 | <code>false</code>, then there is a good chance that the last few
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48 | logs events are not actually written to persistent media if and
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49 | when the application crashes.
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50 |
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51 | <p>The <code>immediateFlush</code> variable is set to
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52 | <code>true</code> by default.
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53 |
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54 | */
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55 | bool immediateFlush;
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56 |
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57 | /**
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58 | The encoding to use when opening an input stream.
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59 | <p>The <code>encoding</code> variable is set to <code>""</code> by
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60 | default which results in the utilization of the system's default
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61 | encoding. */
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62 | LogString encoding;
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63 |
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64 | /**
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65 | * This is the {@link Writer Writer} where we will write to.
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66 | */
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67 | log4cxx::helpers::WriterPtr writer;
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68 |
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69 |
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70 | public:
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71 | DECLARE_ABSTRACT_LOG4CXX_OBJECT(WriterAppender)
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72 | BEGIN_LOG4CXX_CAST_MAP()
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73 | LOG4CXX_CAST_ENTRY(WriterAppender)
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74 | LOG4CXX_CAST_ENTRY_CHAIN(AppenderSkeleton)
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75 | END_LOG4CXX_CAST_MAP()
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76 |
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77 | /**
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78 | This default constructor does nothing.*/
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79 | WriterAppender();
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80 | protected:
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81 | WriterAppender(const LayoutPtr& layout,
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82 | log4cxx::helpers::WriterPtr& writer);
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83 | WriterAppender(const LayoutPtr& layout);
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84 |
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85 | public:
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86 | ~WriterAppender();
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87 |
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88 | /**
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89 | Derived appenders should override this method if option structure
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90 | requires it.
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91 | */
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92 | virtual void activateOptions(log4cxx::helpers::Pool& pool);
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93 |
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94 | /**
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95 | If the <b>ImmediateFlush</b> option is set to
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96 | <code>true</code>, the appender will flush at the end of each
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97 | write. This is the default behavior. If the option is set to
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98 | <code>false</code>, then the underlying stream can defer writing
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99 | to physical medium to a later time.
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100 |
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101 | <p>Avoiding the flush operation at the end of each append results in
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102 | a performance gain of 10 to 20 percent. However, there is safety
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103 | tradeoff involved in skipping flushing. Indeed, when flushing is
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104 | skipped, then it is likely that the last few log events will not
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105 | be recorded on disk when the application exits. This is a high
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106 | price to pay even for a 20% performance gain.
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107 | */
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108 | void setImmediateFlush(bool value);
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109 | /**
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110 | Returns value of the <b>ImmediateFlush</b> option.
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111 | */
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112 | bool getImmediateFlush() const { return immediateFlush; }
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113 |
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114 | /**
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115 | This method is called by the AppenderSkeleton#doAppend
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116 | method.
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117 |
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118 | <p>If the output stream exists and is writable then write a log
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119 | statement to the output stream. Otherwise, write a single warning
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120 | message to <code>stderr</code>.
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121 |
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122 | <p>The format of the output will depend on this appender's
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123 | layout.
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124 |
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125 | */
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126 | virtual void append(const spi::LoggingEventPtr& event, log4cxx::helpers::Pool& p);
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127 |
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128 |
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129 | protected:
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130 | /**
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131 | This method determines if there is a sense in attempting to append.
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132 |
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133 | <p>It checks whether there is a set output target and also if
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134 | there is a set layout. If these checks fail, then the boolean
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135 | value <code>false</code> is returned. */
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136 | virtual bool checkEntryConditions() const;
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137 |
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138 |
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139 | public:
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140 | /**
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141 | Close this appender instance. The underlying stream or writer is
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142 | also closed.
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143 |
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144 | <p>Closed appenders cannot be reused.
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145 | */
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146 | virtual void close();
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147 |
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148 | protected:
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149 | /**
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150 | * Close the underlying {@link log4cxx::helpers::Writer}.
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151 | * */
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152 | void closeWriter();
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153 |
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154 | /**
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155 | Returns an OutputStreamWriter when passed an OutputStream. The
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156 | encoding used will depend on the value of the
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157 | <code>encoding</code> property. If the encoding value is
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158 | specified incorrectly the writer will be opened using the default
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159 | system encoding (an error message will be printed to the loglog. */
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160 | virtual log4cxx::helpers::WriterPtr createWriter(
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161 | log4cxx::helpers::OutputStreamPtr& os);
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162 |
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163 | public:
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164 | LogString getEncoding() const;
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165 | void setEncoding(const LogString& value);
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166 | void setOption(const LogString& option,
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167 | const LogString& value);
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168 |
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169 | /**
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170 | <p>Sets the Writer where the log output will go. The
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171 | specified Writer must be opened by the user and be
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172 | writable.
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173 |
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174 | <p>The <code>java.io.Writer</code> will be closed when the
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175 | appender instance is closed.
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176 |
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177 |
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178 | <p><b>WARNING:</b> Logging to an unopened Writer will fail.
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179 | <p>
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180 | @param writer An already opened Writer. */
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181 | void setWriter(const log4cxx::helpers::WriterPtr& writer);
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182 |
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183 | virtual bool requiresLayout() const;
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184 |
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185 | protected:
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186 | /**
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187 | Actual writing occurs here.
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188 | */
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189 | virtual void subAppend(const spi::LoggingEventPtr& event, log4cxx::helpers::Pool& p);
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190 |
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191 |
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192 | /**
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193 | Write a footer as produced by the embedded layout's
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194 | Layout#appendFooter method. */
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195 | virtual void writeFooter(log4cxx::helpers::Pool& p);
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196 |
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197 | /**
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198 | Write a header as produced by the embedded layout's
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199 | Layout#appendHeader method. */
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200 | virtual void writeHeader(log4cxx::helpers::Pool& p);
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201 |
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202 | private:
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203 | //
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204 | // prevent copy and assignment
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205 | WriterAppender(const WriterAppender&);
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206 | WriterAppender& operator=(const WriterAppender&);
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207 | };
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208 |
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209 | LOG4CXX_PTR_DEF(WriterAppender);
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210 |
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211 | } //namespace log4cxx
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212 |
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213 | #if defined(_MSC_VER)
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214 | #pragma warning ( pop )
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215 | #endif
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216 |
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217 | #endif //_LOG4CXX_WRITER_APPENDER_H
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