Top Description Fields Constructors Methods
com.google.common.base.internal

public Class Finalizer

extends Object
implements Runnable
Class Inheritance
All Implemented Interfaces
java.lang.Runnable
Imports
java.lang.ref.PhantomReference, .Reference, .ReferenceQueue, .WeakReference, java.lang.reflect.Constructor, .Field, .Method, java.util.logging.Level, .Logger, javax.annotation.CheckForNull
Thread that finalizes referents. All references should implement com.google.common.base.FinalizableReference.

While this class is public, we consider it to be *internal* and not part of our published API. It is public so we can access it reflectively across class loaders in secure environments.

This class can't depend on other Guava code. If we were to load this class in the same class loader as the rest of Guava, this thread would keep an indirect strong reference to the class loader and prevent it from being garbage collected. This poses a problem for environments where you want to throw away the class loader. For example, dynamically reloading a web application or unloading an OSGi bundle.

com.google.common.base.FinalizableReferenceQueue loads this class in its own class loader. That way, this class doesn't prevent the main class loader from getting garbage collected, and this class can detect when the main class loader has been garbage collected and stop itself.

Field Summary

Modifier and TypeField and Description
private static final Constructor<Thread>
bigThreadConstructor

private static final String
FINALIZABLE_REFERENCE

Name of FinalizableReference.class.

private final WeakReference<Class<?>>
finalizableReferenceClassReference

private final PhantomReference<Object>
frqReference

private static final Field
inheritableThreadLocals

private static final Logger
logger

private final ReferenceQueue<Object>
queue

Constructor Summary

AccessConstructor and Description
private
Finalizer(Class<?> finalizableReferenceClass, ReferenceQueue<Object> queue, PhantomReference<Object> frqReference)

Constructs a new finalizer thread.

Method Summary

Modifier and TypeMethod and Description
private boolean

Returns:

true if the caller should continue, false if the associated FinalizableReferenceQueue is no longer referenced.
cleanUp(Reference<?> reference)

Cleans up a single reference.

private static Constructor<Thread>
getBigThreadConstructor()

private Method
getFinalizeReferentMethod()

Looks up FinalizableReference.finalizeReferent() method.

private static Field
getInheritableThreadLocalsField()

public void
run()

Implements java.lang.Runnable.run.

Loops continuously, pulling references off the queue and cleaning them up.
public static void
startFinalizer(Class<?>
FinalizableReference.class.
finalizableReferenceClass, ReferenceQueue<Object>
a reference queue that the thread will poll.
queue, PhantomReference<Object>
a phantom reference to the FinalizableReferenceQueue, which will be queued either when the FinalizableReferenceQueue is no longer referenced anywhere, or when its close() method is called.
frqReference)

Starts the Finalizer thread.

Inherited from java.lang.Object:
cloneequalsfinalizegetClasshashCodenotifynotifyAlltoStringwaitwaitwait

Field Detail

bigThreadConstructorback to summary
private static final Constructor<Thread> bigThreadConstructor
Annotations
@CheckForNull
FINALIZABLE_REFERENCEback to summary
private static final String FINALIZABLE_REFERENCE

Name of FinalizableReference.class.

finalizableReferenceClassReferenceback to summary
private final WeakReference<Class<?>> finalizableReferenceClassReference
frqReferenceback to summary
private final PhantomReference<Object> frqReference
inheritableThreadLocalsback to summary
private static final Field inheritableThreadLocals
Annotations
@CheckForNull
loggerback to summary
private static final Logger logger
queueback to summary
private final ReferenceQueue<Object> queue

Constructor Detail

Finalizerback to summary
private Finalizer(Class<?> finalizableReferenceClass, ReferenceQueue<Object> queue, PhantomReference<Object> frqReference)

Constructs a new finalizer thread.

Method Detail

cleanUpback to summary
private boolean cleanUp(Reference<?> reference)

Cleans up a single reference. Catches and logs all throwables.

Returns:boolean

true if the caller should continue, false if the associated FinalizableReferenceQueue is no longer referenced.

getBigThreadConstructorback to summary
private static Constructor<Thread> getBigThreadConstructor()
Annotations
@CheckForNull
getFinalizeReferentMethodback to summary
private Method getFinalizeReferentMethod()

Looks up FinalizableReference.finalizeReferent() method.

Annotations
@CheckForNull
getInheritableThreadLocalsFieldback to summary
private static Field getInheritableThreadLocalsField()
Annotations
@CheckForNull
runback to summary
public void run()

Implements java.lang.Runnable.run.

Loops continuously, pulling references off the queue and cleaning them up.

Annotations
@SuppressWarnings:InfiniteLoopStatement
@Override
startFinalizerback to summary
public static void startFinalizer(Class<?> finalizableReferenceClass, ReferenceQueue<Object> queue, PhantomReference<Object> frqReference)

Starts the Finalizer thread. FinalizableReferenceQueue calls this method reflectively.

Parameters
finalizableReferenceClass:Class<?>

FinalizableReference.class.

queue:ReferenceQueue<Object>

a reference queue that the thread will poll.

frqReference:PhantomReference<Object>

a phantom reference to the FinalizableReferenceQueue, which will be queued either when the FinalizableReferenceQueue is no longer referenced anywhere, or when its close() method is called.