/*
* 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;
}
}