edu.stanford.nlp.util.concurrent

Class SynchronizedInterner<T>

java.lang.Object

edu.stanford.nlp.util.concurrent.SynchronizedInterner<T>

public class SynchronizedInterner<T>
extends Object

For interning (canonicalizing) things in a multi-threaded environment.

Maps any object to a unique interned version which .equals the presented object. If presented with a new object which has no previous interned version, the presented object becomes the interned version. You can tell if your object has been chosen as the new unique representative by checking whether o == intern(o). The interners use a concurrent map with weak references, meaning that if the only pointers to an interned item are the interners' backing maps, that item can still be garbage collected. Since the gc thread can silently remove things from the backing map, there's no public way to get the backing map, but feel free to add one at your own risk.

Note that in general it is just as good or better to use the static SynchronizedInterner.globalIntern() method rather than making an instance of SynchronizedInterner and using the instance-level intern().

Author:

Ilya Sherman

See Also:

Interner

Field Summary

Fields

Modifier and Type	Field and Description
protected Interner<T>	delegate
protected static Object	globalMutex
protected static SynchronizedInterner<Object>	interner
protected Object	mutex

Constructor Summary

Constructors

Constructor and Description
SynchronizedInterner(Interner<T> delegate)
SynchronizedInterner(Interner<T> delegate, Object mutex)

Method Summary

Methods

Modifier and Type	Method and Description
void	clear()
static SynchronizedInterner<Object>	getGlobal() For getting the instance that global methods use.
static <T> T	globalIntern(T o) Returns a unique object o' that .equals the argument o.
T	intern(T o) Returns a unique object o' that .equals the argument o.
Set<T>	internAll(Set<T> s) Returns a Set such that each element in the returned set is a unique object e' that .equals the corresponding element e in the original set.
static void	main(String[] args) Test method: interns its arguments and says whether they == themselves.
static SynchronizedInterner<Object>	setGlobal(Interner<Object> delegate) For supplying a new instance for the global methods to use.
int	size()

Methods inherited from class java.lang.Object

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

Field Detail

globalMutex

protected static final Object globalMutex

interner

protected static SynchronizedInterner<Object> interner

delegate

protected final Interner<T> delegate

mutex

protected final Object mutex

Constructor Detail

SynchronizedInterner

public SynchronizedInterner(Interner<T> delegate)

SynchronizedInterner

public SynchronizedInterner(Interner<T> delegate,
                    Object mutex)

Method Detail

getGlobal

public static SynchronizedInterner<Object> getGlobal()

For getting the instance that global methods use.

setGlobal

public static SynchronizedInterner<Object> setGlobal(Interner<Object> delegate)

For supplying a new instance for the global methods to use.

Returns:

the previous global interner.

globalIntern

public static <T> T globalIntern(T o)

Returns a unique object o' that .equals the argument o. If o itself is returned, this is the first request for an object .equals to o.

clear

public void clear()

intern

public T intern(T o)

Returns a unique object o' that .equals the argument o. If o itself is returned, this is the first request for an object .equals to o.

internAll

public Set<T> internAll(Set<T> s)

Returns a Set such that each element in the returned set is a unique object e' that .equals the corresponding element e in the original set.

size

public int size()

main

public static void main(String[] args)
                 throws InterruptedException

Test method: interns its arguments and says whether they == themselves.

Throws:

InterruptedException