org.aspectj.weaver
Class WeakClassLoaderReference

java.lang.Object
  org.aspectj.weaver.WeakClassLoaderReference

Direct Known Subclasses:

BcelWeakClassLoaderReference

public class WeakClassLoaderReference
extends java.lang.Object

Wraps a reference to a classloader inside a WeakReference. This should be used where we do not want the existence of a classloader reference to prevent garbage collection of that classloader (and possibly an associated weaver instance in the case of load time weaving).

In more detail:
When load time weaving, the class Aj maintains a WeakHashMap from the classloader instance to a weaver instance. The aim is that the weaver is around as long as the classloader is and should the classloader be dereferenced then the weaver can also be garbage collected. The problem is that if there are many references to the classloader from within the weaver, these are considered hard references and cause the classloader to be long lived - even if the user of the classloader has dereferenced it in their code. The solution is that the weaver should use instances of WeakClassLoaderReference objects - so that when the users hard reference to the classloader goes, nothing in the weaver will cause it to hang around. There is a big assertion here that the WeakClassLoaderReference instances will not 'lose' their ClassLoader references until the top level ClassLoader reference is null'd. This means there is no need to check for the null case on get() in this WeakReference logic below, because we shouldn't be using this weaver if its associated ClassLoader has been collected. See https://bugs.eclipse.org/bugs/show_bug.cgi?id=210470

Field Summary

protected int

hashcode

Constructor Summary

WeakClassLoaderReference(java.lang.ClassLoader loader)

Method Summary

boolean	equals(java.lang.Object obj)
java.lang.ClassLoader	getClassLoader()
int	hashCode()

Methods inherited from class java.lang.Object

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

Field Detail

hashcode

protected final int hashcode

Constructor Detail

WeakClassLoaderReference

public WeakClassLoaderReference(java.lang.ClassLoader loader)

Method Detail

getClassLoader

public java.lang.ClassLoader getClassLoader()

equals

public boolean equals(java.lang.Object obj)

Overrides:

equals in class java.lang.Object

hashCode

public int hashCode()

Overrides:

hashCode in class java.lang.Object