org.alfresco.util

Class ReadWriteLockExecuter

java.lang.Object

org.alfresco.util.ReadWriteLockExecuter

public abstract class ReadWriteLockExecuter
extends java.lang.Object

Utility object that wraps read and write methods within the context of a ReentrantReadWriteLock. The callback's methods are best-suited to fetching values from a cache or protecting members that need lazy initialization.

Client code should construct an instance of this class for each resource (or set of resources) that need to be protected.

Since:

3.4

Constructor Summary

Constructors

Constructor and Description
ReadWriteLockExecuter() Default constructor

Method Summary

Methods

Modifier and Type	Method and Description
java.lang.Object	execute()
protected abstract java.lang.Object	getWithReadLock() Execute the read-only part of the work.
protected abstract java.lang.Object	getWithWriteLock() Execute the write part of the work.

Methods inherited from class java.lang.Object

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

Constructor Detail

ReadWriteLockExecuter

public ReadWriteLockExecuter()

Default constructor

Method Detail

getWithReadLock

protected abstract java.lang.Object getWithReadLock()
                                             throws java.lang.Throwable

Execute the read-only part of the work.

Returns:

Returns a value of interest or null if the ReadWriteLockExecuter.getWithWriteLock() method must be called

Throws:

java.lang.Throwable - all checked exceptions are wrapped in a RuntimeException

getWithWriteLock

protected abstract java.lang.Object getWithWriteLock()
                                              throws java.lang.Throwable

Execute the write part of the work.

NOTE: It is important to perform a double-check on the resource before assuming it is not null; there is a window between the ReadWriteLockExecuter.getWithReadLock() and the ReadWriteLockExecuter.getWithWriteLock() during which another thread may have populated the resource of interest.

Returns:

Returns the value of interest of null

Throws:

java.lang.Throwable - all checked exceptions are wrapped in a RuntimeException

execute

public java.lang.Object execute()