ListenableWeakReference (JOSM)

java.lang.Object
- java.lang.ref.Reference<T>
- - java.lang.ref.WeakReference<T>
  - - org.openstreetmap.josm.tools.ListenableWeakReference<T>

Type Parameters:

T - The weak reference

Direct Known Subclasses:

AbstractProperty.WeakPreferenceAdapter
```
public class ListenableWeakReference<T>
extends java.lang.ref.WeakReference<T>
```
This is a special weak reference that notifies a listener when it is no longer available. A special dereferenced-thread is used for this, so make sure your code is thread-safe.

Since:

12181

Field Summary

Fields
Modifier and Type	Field	Description
`private static java.lang.ref.ReferenceQueue<java.lang.Object>`	`GLOBAL_QUEUE`
`private java.lang.Runnable`	`runOnDereference`
`private static java.lang.Thread`	`thread`

Constructor Summary

Constructors
Constructor	Description
`ListenableWeakReference(T referent)`	Create a new `ListenableWeakReference`
`ListenableWeakReference(T referent, java.lang.Runnable runOnDereference)`	Create a new `ListenableWeakReference`

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`private static void`	`clean()`
`private static void`	`ensureQueueStarted()`
`protected void`	`onDereference()`	This method is called after the object is dereferenced.

Methods inherited from class java.lang.ref.Reference
clear, clone, enqueue, get, isEnqueued, reachabilityFence

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

- Field Detail
  - GLOBAL_QUEUE
```
private static final java.lang.ref.ReferenceQueue<java.lang.Object> GLOBAL_QUEUE
```
  - thread
```
private static java.lang.Thread thread
```
  - runOnDereference
```
private final java.lang.Runnable runOnDereference
```
- Constructor Detail
  - ListenableWeakReference
```
public ListenableWeakReference(T referent)
```
    Create a new ListenableWeakReference
    
    Parameters:
    
    referent - The object that is referenced
  - ListenableWeakReference
```
public ListenableWeakReference(T referent,
                               java.lang.Runnable runOnDereference)
```
    Create a new ListenableWeakReference
    
    Parameters:
    
    referent - The object that is referenced
    
    runOnDereference - The runnable to run when the object is no longer referenced.
- Method Detail
  - onDereference
```
protected void onDereference()
```
    This method is called after the object is dereferenced.
  - ensureQueueStarted
```
private static void ensureQueueStarted()
```
  - clean
```
private static void clean()
```