Finalizer

java.lang.Object
- jnr.ffi.util.ref.internal.Finalizer

All Implemented Interfaces:

java.lang.Runnable
```
public class Finalizer
extends java.lang.Object
implements java.lang.Runnable
```
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 Google Collections code. If we were to load this class in the same class loader as the rest of Google Collections, 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

Fields
Modifier and Type	Field	Description
`private static java.lang.String`	`FINALIZABLE_REFERENCE`	Name of FinalizableReference.class.
`private java.lang.ref.WeakReference<java.lang.Class<?>>`	`finalizableReferenceClassReference`
`private java.lang.ref.PhantomReference<java.lang.Object>`	`frqReference`
`private static java.lang.reflect.Field`	`inheritableThreadLocals`
`private static java.lang.reflect.Constructor<java.lang.Thread>`	`inheritableThreadlocalsConstructor`
`private static java.util.logging.Logger`	`logger`
`private java.lang.ref.ReferenceQueue<java.lang.Object>`	`queue`
`private java.lang.Thread`	`thread`

Constructor Summary

Constructors
Modifier Constructor Description

private Finalizer(java.lang.Class<?> finalizableReferenceClass, java.lang.Object frq)
Constructs a new finalizer thread.

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`private boolean`	`cleanUp(java.lang.ref.Reference<?> reference)`	Cleans up a single reference.
`private java.lang.reflect.Method`	`getFinalizeReferentMethod()`	Looks up FinalizableReference.finalizeReferent() method.
`static java.lang.reflect.Constructor<java.lang.Thread>`	`getInheritableThreadLocalsConstructor()`
`static java.lang.reflect.Field`	`getInheritableThreadLocalsField()`
`void`	`run()`	Loops continuously, pulling references off the queue and cleaning them up.
`void`	`start()`
`static java.lang.ref.ReferenceQueue<java.lang.Object>`	`startFinalizer(java.lang.Class<?> finalizableReferenceClass, java.lang.Object frq)`	Starts the Finalizer thread.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

logger

private static final java.util.logging.Logger logger

FINALIZABLE_REFERENCE
```
private static final java.lang.String FINALIZABLE_REFERENCE
```
Name of FinalizableReference.class.

See Also:

Constant Field Values

thread
```
private java.lang.Thread thread
```

finalizableReferenceClassReference

private final java.lang.ref.WeakReference<java.lang.Class<?>> finalizableReferenceClassReference

frqReference

private final java.lang.ref.PhantomReference<java.lang.Object> frqReference

queue

private final java.lang.ref.ReferenceQueue<java.lang.Object> queue

inheritableThreadLocals

private static final java.lang.reflect.Field inheritableThreadLocals

inheritableThreadlocalsConstructor

private static final java.lang.reflect.Constructor<java.lang.Thread> inheritableThreadlocalsConstructor

Constructor Detail

Finalizer

private Finalizer(java.lang.Class<?> finalizableReferenceClass,
                  java.lang.Object frq)

Constructs a new finalizer thread.

Method Detail
- startFinalizer
```
public static java.lang.ref.ReferenceQueue<java.lang.Object> startFinalizer(java.lang.Class<?> finalizableReferenceClass,
                                                                            java.lang.Object frq)
```
  Starts the Finalizer thread. FinalizableReferenceQueue calls this method reflectively.
  
  Parameters:
  
  finalizableReferenceClass - FinalizableReference.class
  
  frq - reference to instance of FinalizableReferenceQueue that started this thread
  
  Returns:
  
  ReferenceQueue which Finalizer will poll
- start
```
public void start()
```
- run
```
public void run()
```
  Loops continuously, pulling references off the queue and cleaning them up.
  
  Specified by:
  
  run in interface java.lang.Runnable
- cleanUp
```
private boolean cleanUp(java.lang.ref.Reference<?> reference)
```
  Cleans up a single reference. Catches and logs all throwables.
- getFinalizeReferentMethod
```
private java.lang.reflect.Method getFinalizeReferentMethod()
```
  Looks up FinalizableReference.finalizeReferent() method.
- getInheritableThreadLocalsField
```
public static java.lang.reflect.Field getInheritableThreadLocalsField()
```
- getInheritableThreadLocalsConstructor
```
public static java.lang.reflect.Constructor<java.lang.Thread> getInheritableThreadLocalsConstructor()
```