org.h2.util

Class CloseWatcher

java.lang.Object

java.lang.ref.Reference<T>

java.lang.ref.PhantomReference<Object>

org.h2.util.CloseWatcher

public class CloseWatcher
extends PhantomReference<Object>

A phantom reference to watch for unclosed objects.

Field Summary

Fields

Modifier and Type	Field and Description
static ReferenceQueue<Object>	queue The queue (might be set to null at any time).
static HashSet<CloseWatcher>	refs The reference set.

Constructor Summary

Constructors

Constructor and Description
CloseWatcher(Object referent, ReferenceQueue<Object> q, Closeable closeable)

Method Summary

Methods

Modifier and Type	Method and Description
Closeable	getCloseable()
String	getOpenStackTrace() Get the open stack trace or null if none.
static CloseWatcher	pollUnclosed() Check for an collected object.
static CloseWatcher	register(Object o, Closeable closeable, boolean stackTrace) Register an object.
static void	unregister(CloseWatcher w) Unregister an object, so it is no longer tracked.

Methods inherited from class java.lang.ref.PhantomReference

get

Methods inherited from class java.lang.ref.Reference

clear, enqueue, isEnqueued

Methods inherited from class java.lang.Object

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

Field Detail

queue

public static ReferenceQueue<Object> queue

The queue (might be set to null at any time).

refs

public static HashSet<CloseWatcher> refs

The reference set. Must keep it, otherwise the references are garbage collected first and thus never enqueued.

Constructor Detail

CloseWatcher

public CloseWatcher(Object referent,
            ReferenceQueue<Object> q,
            Closeable closeable)

Method Detail

pollUnclosed

public static CloseWatcher pollUnclosed()

Check for an collected object.

Returns:

the first watcher

register

public static CloseWatcher register(Object o,
                    Closeable closeable,
                    boolean stackTrace)

Register an object. Before calling this method, pollUnclosed() should be called in a loop to remove old references.

Parameters:

o - the object

closeable - the object to close

stackTrace - whether the stack trace should be registered (this is relatively slow)

Returns:

the close watcher

unregister

public static void unregister(CloseWatcher w)

Unregister an object, so it is no longer tracked.

Parameters:

w - the reference

getOpenStackTrace

public String getOpenStackTrace()

Get the open stack trace or null if none.

Returns:

the open stack trace

getCloseable

public Closeable getCloseable()