src/java/org/apache/log4j/xml/XMLLayout.java

/*
 * Copyright (C) The Apache Software Foundation. All rights reserved.
 *
 * This software is published under the terms of the Apache Software
 * License version 1.1, a copy of which has been included with this
 * distribution in the LICENSE.APL file.  */

// Contributors:   Mathias Bogaert

package org.apache.log4j.xml;

import org.apache.log4j.Layout;
import org.apache.log4j.spi.LoggingEvent;
import org.apache.log4j.spi.LocationInfo;
import org.apache.log4j.helpers.OptionConverter;
import org.apache.log4j.helpers.DateLayout;

/**
   The output of the XMLLayout consists of a series of log4j:event
   elements as defined in the <a
   href="doc-files/log4j.dtd">log4j.dtd</a>. It does not output a
   complete well-formed XML file. The output is designed to be
   included as an <em>external entity</em> in a separate file to form
   a correct XML file.

   <p>For example, if <code>abc</code> is the name of the file where
   the XMLLayout ouput goes, then a well-formed XML file would be:

   <pre>
   &lt;?xml version="1.0" ?&gt;

   &lt;!DOCTYPE log4j:eventSet SYSTEM "log4j.dtd" [&lt;!ENTITY data SYSTEM "abc"&gt;]&gt;

   &lt;log4j:eventSet xmlns:log4j="http://jakarta.apache.org/log4j"&gt;
       &nbsp;&nbsp;&data;
   &lt;/log4j:eventSet&gt;
   </pre>

   <p>This approach enforces the independence of the XMLLayout and the
   appender where it is embedded.

   @author Ceki  G&uuml;lc&uuml;
   @since 0.9.0 */
public class XMLLayout extends Layout {

  /**
     This is a string constant to name the option for setting the
     location information flag. Current value of this string constant
     is <b>LocationInfo</b>. 

     <p>See the {@link #setOption(java.lang.String, java.lang.String)}
     method for the meaning of this option.  

     <p>Note all option keys are case sensitive.
     
     @deprecated Options are now handled using the JavaBeans paradigm.
     This constant is not longer needed and will be removed in the
     <em>near</em> term.
  */
  public static final String LOCATION_INFO_OPTION = "LocationInfo";

  private  final int DEFAULT_SIZE = 256;
  private final int UPPER_LIMIT = 2048;

  private StringBuffer buf = new StringBuffer(DEFAULT_SIZE);
  private boolean locationInfo = false;

  /**
     @deprecated We now use JavaBeans introspection to configure
     components. Options strings are no longer needed.
  */
  public
  String[] getOptionStrings() {
    return new String[]{LOCATION_INFO_OPTION};
  }

  /**

     The XMLLayout specific options are:

     <p>The <b>LocationInfo</b> option takes a boolean value. If true,
     the output will include location information. By default no
     location information is sent to the server.
  
     @deprecated Use the setter method for the option directly instead
     of the generic <code>setOption</code> method. 

  */
  public
  void setOption(String key, String value) {

    if(value == null) return;
    if (key.equals(LOCATION_INFO_OPTION)) {
      locationInfo = OptionConverter.toBoolean(value, locationInfo);    
    } 
  }
  
  /**
     The <b>LocationInfo</b> option takes a boolean value. By
     default, it is set to false which means there will be no location
     information output by this layout. If the the option is set to
     true, then the file name and line number of the statement
     at the origin of the log statement will be output. 

     <p>If you are embedding this layout within an {@link
     org.apache.log4j.net.SMTPAppender} then make sure to set the
     <b>LocationInfo</b> option of that appender as well.
   */
  public
  void setLocationInfo(boolean flag) {
    locationInfo = flag;
  }
  
  /**
     Returns the current value of the <b>LocationInfo</b> option.
   */
  public
  boolean getLocationInfo() {
    return locationInfo;
  }
  
  public
  void activateOptions() {
  }


  /**
     Formats a {@link LoggingEvent} in conformance with the log4j.dtd.  */
  public
  String format(LoggingEvent event) {

    // Reset working buffer. If the buffer is too large, then we need a new
    // one in order to avoid the penalty of creating a large array.
    if(buf.capacity() > UPPER_LIMIT) {
      buf = new StringBuffer(DEFAULT_SIZE);
    } else {
      buf.setLength(0);
    }
    
    // We yield to the \r\n heresy.

    buf.append("<log4j:event category=\"");
    buf.append(event.categoryName);
    buf.append("\" timestamp=\"");
    buf.append(event.timeStamp);
    buf.append("\" priority=\"");
    buf.append(event.priority);
    buf.append("\" thread=\"");
    buf.append(event.getThreadName());
    buf.append("\">\r\n");


       buf.append("<log4j:message><![CDATA[");
       buf.append(event.getRenderedMessage());
       buf.append("]]></log4j:message>\r\n");       

       String ndc = event.getNDC();
       if(ndc != null) {
	 buf.append("<log4j:NDC><![CDATA[");
	 buf.append(ndc);
	 buf.append("]]></log4j:NDC>\r\n");       
       }

       String[] s = event.getThrowableStrRep();
       if(s != null) {
	 buf.append("<log4j:throwable><![CDATA[");
	 for(int i = 0; i < s.length; i++) {
	   buf.append(s[i]);
	 }
	 buf.append("]]></log4j:throwable>\r\n");
       }

       if(locationInfo) { 
	 LocationInfo locationInfo = event.getLocationInformation();	
	 buf.append("<log4j:locationInfo class=\"");
	 buf.append(locationInfo.getClassName());
	 buf.append("\" method=\"");
	 buf.append(locationInfo.getMethodName());
	 buf.append("\" file=\"");
	 buf.append(locationInfo.getFileName());
	 buf.append("\" line=\"");
	 buf.append(locationInfo.getLineNumber());
	 buf.append("\"/>\r\n");
       }

    buf.append("</log4j:event>\r\n\r\n");

    return buf.toString();
  }
  
  /**
     The XMLLayout prints and does not ignore exceptions. Hence the
     return value <code>false</code>.
  */
  public
  boolean ignoresThrowable() {
    return false;
  }
}