com.protomatter.util
Class StackTraceUtil

java.lang.Object
  |
  +--com.protomatter.util.StackTraceUtil

public class StackTraceUtil

extends java.lang.Object

A utility class for parsing stack traces.

Determining the stack information at runtime is a relatively expensive operation. I've tested this on a 650MHz PIII Coppermine Sony Vaio laptop running RedHat Linux 7.2, kernel 2.4.9, I saw these results with single-threaded tests:

Classic VM (build JDK-1.2.2_012, green threads, nojit)	Average 0.73543ms
Classic VM (build 1.3.1, J2RE 1.3.1 IBM build cxia32131-20020410 (JIT enabled: jitc))	Average 0.31817ms
Java(TM) 2 Runtime Environment, Standard Edition (build 1.3.1_03-b03)	Average 0.18201ms
Java HotSpot(TM) Client VM (build 1.4.0-b92, mixed mode)	Average 0.1024ms
JRockit Virtual Machine (build 3.1.4-dax.appeal.se-20020319-1000) Native Threads, Generational Concurrent Garbage Collector	Average 0.0486ms

If possible, this class loads an implementation of itself that uses new APIs available in JDK 1.4 to improve performance. Under JDK 1.2 and 1.3, this class parses a stack trace to determine call stack information.

Also, under the IBM and JRockit JVMs, line numbers are usually not available. They may or may not be availble under other JVMs because the JIT may or may not strip that information from stack traces.

Sustained, rapid creation of java.lang.Throwable objects under the IBM JDK repeatedly caused JVM deadlocks. This should not be an issue in actual systems, but it is concerning.

Constructor Summary

protected

StackTraceUtil() Protected constructor so nobody instantiates this class.

Method Summary

protected StackTraceInfo	getInfo(int stackOffset)
static void	main(java.lang.String[] args) Performance test rig.
static StackTraceInfo	whereAmI() Determine what class and method you are in.
static StackTraceInfo	whereAmI(int stackOffset) Determine what class and method you are in.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

StackTraceUtil

protected StackTraceUtil()

Protected constructor so nobody instantiates this class.

Method Detail

whereAmI

public static StackTraceInfo whereAmI()

Determine what class and method you are in.

whereAmI

public static StackTraceInfo whereAmI(int stackOffset)

Determine what class and method you are in. The offset is how many levels above where this method is called.

getInfo

protected StackTraceInfo getInfo(int stackOffset)

main

public static void main(java.lang.String[] args)

Performance test rig. Optional command-line arguments are the number of threads (default is 5), and number of calls per thread (default is 10,000).