Skip to content
master
Go to file
Code

Latest commit

 

Git stats

Files

Permalink
Failed to load latest commit information.
Type
Name
Latest commit message
Commit time
src
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

README.md

The Allocation Instrumenter is a Java agent written using the java.lang.instrument API and ASM. Each allocation in your Java program is instrumented; a user-defined callback is invoked on each allocation.

How to get it

The latest release is available from Maven Central as:

<dependency>
  <groupId>com.google.code.java-allocation-instrumenter</groupId>
  <artifactId>java-allocation-instrumenter</artifactId>
  <version>3.3.0</version>
</dependency>

Basic usage

In order to write your own allocation tracking code, you have to implement the Sampler interface and pass an instance of that to AllocationRecorder.addSampler():

AllocationRecorder.addSampler(new Sampler() {
  public void sampleAllocation(int count, String desc, Object newObj, long size) {
    System.out.println("I just allocated the object " + newObj +
      " of type " + desc + " whose size is " + size);
    if (count != -1) { System.out.println("It's an array of size " + count); }
  }
});

You can also use the allocation instrumenter to instrument constructors of particular classes. You do this by instantiating a ConstructorCallback and passing it to ConstructorInstrumenter.instrumentClass():

try {
  ConstructorInstrumenter.instrumentClass(
      Thread.class, new ConstructorCallback<Thread>() {
        @Override public void sample(Thread t) {
          System.out.println("Instantiating a thread");
        }
      });
} catch (UnmodifiableClassException e) {
  System.out.println("Class cannot be modified");
}

For more information on how to get or use the allocation instrumenter, see Getting Started.