oracle.javatools.db.util

Class SynchronizedBuildCache<T extends DBObject>

java.lang.Object

oracle.javatools.db.util.SynchronizedBuildCache<T>

public class SynchronizedBuildCache<T extends DBObject>
extends java.lang.Object

A thread-safe cache of DBObjects. If trying to add a DBObject to the cache when it already is there, the add operation blocks until the object is removed (unless the object is being added by the same thread, in which case the add operation returns false). This is used by builder classes to ensure that they do not build the same object at the same time. Strict equality (i.e. "==") is used for determining whether the objects are the same. This is intended to be used as a static cache as different threads are likely to use different builder instances. Recommended usage is to define a static SynchronizedBuildCache in the builder class. Just before building an object, it should be added to this cache. After building, the object should be removed via a try-finally mechanism.

Since:

12

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static interface	SynchronizedBuildCache.BuildCacheListener<C extends DBObject> Clients of SynchronizedBuildCache may choose to register an implementation of BuildCacheListener for test and/or diagnostic purposes.

Constructor Summary

Constructors

Constructor and Description
SynchronizedBuildCache()

Method Summary

Modifier and Type	Method and Description
boolean	add(T object) Add the object to the cache.
boolean	addBuildCacheListener(SynchronizedBuildCache.BuildCacheListener<T> listener) Adds a listener to the build cache, which clients can use for diagnostic or testing purposes.
boolean	contains(T object) Tests whether the given object is currently cached (i.e.
boolean	remove(T object) Removes the given object from the cache.
boolean	removeBuildCacheListener(SynchronizedBuildCache.BuildCacheListener<T> listener) Removes a listener for this build cache.

Methods inherited from class java.lang.Object

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

Constructor Detail

SynchronizedBuildCache

public SynchronizedBuildCache()

Method Detail

addBuildCacheListener

public boolean addBuildCacheListener(SynchronizedBuildCache.BuildCacheListener<T> listener)

Adds a listener to the build cache, which clients can use for diagnostic or testing purposes.

Parameters:

listener -

Returns:

true if listener was added successfully

removeBuildCacheListener

public boolean removeBuildCacheListener(SynchronizedBuildCache.BuildCacheListener<T> listener)

Removes a listener for this build cache. Does nothing if the listener is null or has not been previously added.

Parameters:

listener -

Returns:

true if listener was removed

add

public boolean add(T object)
            throws java.lang.InterruptedException

Add the object to the cache. If the object is already in the cache, this blocks until the object is removed. If the same thread calls this method twice on the same object without calling remove first, then this method returns false and does not update the cache.

Parameters:

object - the DBObject instance to add to the cache. If null, this method returns immediately.

Returns:

true, if added. This method returns false only if a null parameter was passed in or the same thread attempts to add the same object to the cache.

Throws:

java.lang.InterruptedException

remove

public boolean remove(T object)

Removes the given object from the cache.

Parameters:

object - the object to remove. Does nothing, if null.

contains

public boolean contains(T object)

Tests whether the given object is currently cached (i.e. has been added and not removed).

Parameters:

object - the object to test

Returns:

true if the given object is current in this build cache.