org.apache.log4j.spi.LocationInfo Maven / Gradle / Ivy
/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You 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
package org.apache.log4j.spi;
import org.apache.log4j.Layout;
import org.apache.log4j.helpers.LogLog;
import java.io.PrintWriter;
import java.io.StringWriter;
import java.io.InterruptedIOException;
import java.lang.reflect.Method;
import java.lang.reflect.InvocationTargetException;
/**
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
fully.qualified.classname.of.caller.methodName(Filename.java:line)
*/
public String fullInfo;
private static StringWriter sw = new StringWriter();
private static PrintWriter pw = new PrintWriter(sw);
private static Method getStackTraceMethod;
private static Method getClassNameMethod;
private static Method getMethodNameMethod;
private static Method getFileNameMethod;
private static Method getLineNumberMethod;
/**
When location information is not available the constant
NA is returned. Current value of this string
constant is ?. */
public final static String NA = "?";
static final long serialVersionUID = -1325822038990805636L;
/**
* NA_LOCATION_INFO is provided for compatibility with log4j 1.3.
* @since 1.2.15
*/
public static final LocationInfo NA_LOCATION_INFO =
new LocationInfo(NA, NA, NA, NA);
// Check if we are running in IBM's visual age.
static boolean inVisualAge = false;
static {
try {
inVisualAge = Class.forName("com.ibm.uvm.tools.DebugSupport") != null;
LogLog.debug("Detected IBM VisualAge environment.");
} catch(Throwable e) {
// nothing to do
}
try {
Class[] noArgs = null;
getStackTraceMethod = Throwable.class.getMethod("getStackTrace", noArgs);
Class stackTraceElementClass = Class.forName("java.lang.StackTraceElement");
getClassNameMethod = stackTraceElementClass.getMethod("getClassName", noArgs);
getMethodNameMethod = stackTraceElementClass.getMethod("getMethodName", noArgs);
getFileNameMethod = stackTraceElementClass.getMethod("getFileName", noArgs);
getLineNumberMethod = stackTraceElementClass.getMethod("getLineNumber", noArgs);
} catch(ClassNotFoundException ex) {
LogLog.debug("LocationInfo will use pre-JDK 1.4 methods to determine location.");
} catch(NoSuchMethodException ex) {
LogLog.debug("LocationInfo will use pre-JDK 1.4 methods to determine location.");
}
}
/**
Instantiate location information based on a Throwable. We
expect the Throwable t, to be in the format
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)
...
However, we can also deal with JIT compilers that "lose" the
location information, especially between the parentheses.
@param t throwable used to determine location, may be null.
@param fqnOfCallingClass class name of first class considered part of
the logging framework. Location will be site that calls a method on this class.
*/
public LocationInfo(Throwable t, String fqnOfCallingClass) {
if(t == null || fqnOfCallingClass == null)
return;
if (getLineNumberMethod != null) {
try {
Object[] noArgs = null;
Object[] elements = (Object[]) getStackTraceMethod.invoke(t, noArgs);
String prevClass = NA;
for(int i = elements.length - 1; i >= 0; i--) {
String thisClass = (String) getClassNameMethod.invoke(elements[i], noArgs);
if(fqnOfCallingClass.equals(thisClass)) {
int caller = i + 1;
if (caller < elements.length) {
className = prevClass;
methodName = (String) getMethodNameMethod.invoke(elements[caller], noArgs);
fileName = (String) getFileNameMethod.invoke(elements[caller], noArgs);
if (fileName == null) {
fileName = NA;
}
int line = ((Integer) getLineNumberMethod.invoke(elements[caller], noArgs)).intValue();
if (line < 0) {
lineNumber = NA;
} else {
lineNumber = String.valueOf(line);
}
StringBuffer buf = new StringBuffer();
buf.append(className);
buf.append(".");
buf.append(methodName);
buf.append("(");
buf.append(fileName);
buf.append(":");
buf.append(lineNumber);
buf.append(")");
this.fullInfo = buf.toString();
}
return;
}
prevClass = thisClass;
}
return;
} catch(IllegalAccessException ex) {
LogLog.debug("LocationInfo failed using JDK 1.4 methods", ex);
} catch(InvocationTargetException ex) {
if (ex.getTargetException() instanceof InterruptedException
|| ex.getTargetException() instanceof InterruptedIOException) {
Thread.currentThread().interrupt();
}
LogLog.debug("LocationInfo failed using JDK 1.4 methods", ex);
} catch(RuntimeException ex) {
LogLog.debug("LocationInfo failed using JDK 1.4 methods", ex);
}
}
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;
//
// if the next character after the class name exists
// but is not a period, see if the classname is
// followed by a period earlier in the trace.
// Minimizes mistakeningly matching on a class whose
// name is a substring of the desired class.
// See bug 44888.
if (ibegin + fqnOfCallingClass.length() < s.length() &&
s.charAt(ibegin + fqnOfCallingClass.length()) != '.') {
int i = s.lastIndexOf(fqnOfCallingClass + ".");
if (i != -1) {
ibegin = i;
}
}
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);
}
/**
* Appends a location fragment to a buffer to build the
* full location info.
* @param buf StringBuffer to receive content.
* @param fragment fragment of location (class, method, file, line),
* if null the value of NA will be appended.
* @since 1.2.15
*/
private static final void appendFragment(final StringBuffer buf,
final String fragment) {
if (fragment == null) {
buf.append(NA);
} else {
buf.append(fragment);
}
}
/**
* Create new instance.
* @param file source file name
* @param classname class name
* @param method method
* @param line source line number
*
* @since 1.2.15
*/
public LocationInfo(
final String file,
final String classname,
final String method,
final String line) {
this.fileName = file;
this.className = classname;
this.methodName = method;
this.lineNumber = line;
StringBuffer buf = new StringBuffer();
appendFragment(buf, classname);
buf.append(".");
appendFragment(buf, method);
buf.append("(");
appendFragment(buf, file);
buf.append(":");
appendFragment(buf, line);
buf.append(")");
this.fullInfo = buf.toString();
}
/**
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.
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.
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;
}
}