/* * Copyright 1999-2005 The Apache Software Foundation. *  * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at *  *      http://www.apache.org/licenses/LICENSE-2.0 *  * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */// Contributors: Mathias Rupprecht <mmathias.rupprecht@fja.com>package org.apache.log4j.spi;import java.io.StringWriter;import java.io.PrintWriter;import org.apache.log4j.helpers.LogLog;import org.apache.log4j.Layout;/**   The internal representation of caller location information.   @since 0.8.3*/public class LocationInfo implements java.io.Serializable {  /**     Caller's line number.  */  transient String lineNumber;  /**     Caller's file name.  */  transient String fileName;  /**     Caller's fully qualified class name.  */  transient String className;  /**     Caller's method name.  */  transient String methodName;  /**     All available caller information, in the format     <code>fully.qualified.classname.of.caller.methodName(Filename.java:line)</code>    */  public String fullInfo;  private static StringWriter sw = new StringWriter();  private static PrintWriter pw = new PrintWriter(sw);  /**     When location information is not available the constant     <code>NA</code> is returned. Current value of this string     constant is <b>?</b>.  */  public final static String NA = "?";  static final long serialVersionUID = -1325822038990805636L;  // Check if we are running in IBM's visual age.  static boolean inVisualAge = false;  static {    try {      Class dummy = Class.forName("com.ibm.uvm.tools.DebugSupport");      inVisualAge = true;      LogLog.debug("Detected IBM VisualAge environment.");    } catch(Throwable e) {      // nothing to do    }  }  /**     Instantiate location information based on a Throwable. We     expect the Throwable <code>t</code>, to be in the format       <pre>        java.lang.Throwable        ...          at org.apache.log4j.PatternLayout.format(PatternLayout.java:413)          at org.apache.log4j.FileAppender.doAppend(FileAppender.java:183)        at org.apache.log4j.Category.callAppenders(Category.java:131)        at org.apache.log4j.Category.log(Category.java:512)        at callers.fully.qualified.className.methodName(FileName.java:74)	...       </pre>       <p>However, we can also deal with JIT compilers that "lose" the       location information, especially between the parentheses.    */    public LocationInfo(Throwable t, String fqnOfCallingClass) {      if(t == null)	return;      String s;      // Protect against multiple access to sw.      synchronized(sw) {	t.printStackTrace(pw);	s = sw.toString();	sw.getBuffer().setLength(0);      }      //System.out.println("s is ["+s+"].");      int ibegin, iend;      // Given the current structure of the package, the line      // containing "org.apache.log4j.Category." should be printed just      // before the caller.      // This method of searching may not be fastest but it's safer      // than counting the stack depth which is not guaranteed to be      // constant across JVM implementations.      ibegin = s.lastIndexOf(fqnOfCallingClass);      if(ibegin == -1)	return;      ibegin = s.indexOf(Layout.LINE_SEP, ibegin);      if(ibegin == -1)	return;      ibegin+= Layout.LINE_SEP_LEN;      // determine end of line      iend = s.indexOf(Layout.LINE_SEP, ibegin);      if(iend == -1)	return;      // VA has a different stack trace format which doesn't      // need to skip the inital 'at'      if(!inVisualAge) {	// back up to first blank character	ibegin = s.lastIndexOf("at ", iend);	if(ibegin == -1)	  return;	// Add 3 to skip "at ";	ibegin += 3;      }      // everything between is the requested stack item      this.fullInfo = s.substring(ibegin, iend);    }    /**       Return the fully qualified class name of the caller making the       logging request.    */    public    String getClassName() {      if(fullInfo == null) return NA;      if(className == null) {	// Starting the search from '(' is safer because there is	// potentially a dot between the parentheses.	int iend = fullInfo.lastIndexOf('(');	if(iend == -1)	  className = NA;	else {	  iend =fullInfo.lastIndexOf('.', iend);	  // This is because a stack trace in VisualAge looks like:          //java.lang.RuntimeException	  //  java.lang.Throwable()	  //  java.lang.Exception()	  //  java.lang.RuntimeException()	  //  void test.test.B.print()	  //  void test.test.A.printIndirect()	  //  void test.test.Run.main(java.lang.String [])          int ibegin = 0;	  if (inVisualAge) {	    ibegin = fullInfo.lastIndexOf(' ', iend)+1;          }	  if(iend == -1)	    className = NA;	  else	    className = this.fullInfo.substring(ibegin, iend);	}      }      return className;    }    /**       Return the file name of the caller.       <p>This information is not always available.    */    public    String getFileName() {      if(fullInfo == null) return NA;      if(fileName == null) {	int iend = fullInfo.lastIndexOf(':');	if(iend == -1)	  fileName = NA;	else {	  int ibegin = fullInfo.lastIndexOf('(', iend - 1);	  fileName = this.fullInfo.substring(ibegin + 1, iend);	}      }      return fileName;    }    /**       Returns the line number of the caller.       <p>This information is not always available.    */    public    String getLineNumber() {      if(fullInfo == null) return NA;      if(lineNumber == null) {	int iend = fullInfo.lastIndexOf(')');	int ibegin = fullInfo.lastIndexOf(':', iend -1);	if(ibegin == -1)	  lineNumber = NA;	else	  lineNumber = this.fullInfo.substring(ibegin + 1, iend);      }      return lineNumber;    }    /**       Returns the method name of the caller.    */    public    String getMethodName() {      if(fullInfo == null) return NA;      if(methodName == null) {	int iend = fullInfo.lastIndexOf('(');	int ibegin = fullInfo.lastIndexOf('.', iend);	if(ibegin == -1)	  methodName = NA;	else	  methodName = this.fullInfo.substring(ibegin + 1, iend);      }      return methodName;    }}