net.imagej.patcher
Class JavaAgent

java.lang.Object
  net.imagej.patcher.JavaAgent

All Implemented Interfaces:

ClassFileTransformer

public class JavaAgent
extends Object
implements ClassFileTransformer

A Java agent to help with legacy issues.

Author:

Johannes Schindelin

Constructor Summary

JavaAgent()

Method Summary

static void	dontCall(int i)
static void	main(String... args) Writes out a minimal java agent .jar file.
static void	premain(String agentArgs, Instrumentation instrumentation) The premain method started at JVM startup.
static void	stop()
byte[]	transform(ClassLoader loader, String className, Class<?> classBeingRedefined, ProtectionDomain protectionDomain, byte[] classfileBuffer)

Methods inherited from class java.lang.Object

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

Constructor Detail

JavaAgent

public JavaAgent()

Method Detail

stop

public static void stop()

premain

public static void premain(String agentArgs,
                           Instrumentation instrumentation)

The premain method started at JVM startup. When this class is specified as Premain-Class in the manifest and the JVM is started with the option -javaagent:/path/to/ij-legacy.jar then this method is called some time before the main method of the main class is called.

Parameters:

agentArgs - the optional argument passed via -javaagent:ij-legacy.jar=ARGUMENT

instrumentation - the Instrumentation instance passed by the JVM

transform

public byte[] transform(ClassLoader loader,
                        String className,
                        Class<?> classBeingRedefined,
                        ProtectionDomain protectionDomain,
                        byte[] classfileBuffer)
                 throws IllegalClassFormatException

Specified by:

transform in interface ClassFileTransformer

Throws:

IllegalClassFormatException

dontCall

public static void dontCall(int i)

main

public static void main(String... args)
                 throws IOException

Writes out a minimal java agent .jar file.

When trying to debug class loading issues in ij-legacy itself, of course we cannot load the complete ij-legacy.jar as a Java Agent (otherwise it would hide the classes that we want to test with possibly out-dated ones).

This main method can be used to generate a minimal .jar file for use with -javaagent that contains only the LegacyJavaAgent class.

Parameters:

args - the command-line arguments (the first one, if specified, refers to the output file name)

Throws:

IOException