org.mule.module.extension.internal.runtime.resolver

Class CachingValueResolverWrapper<T>

java.lang.Object

org.mule.module.extension.internal.runtime.resolver.CachingValueResolverWrapper<T>

All Implemented Interfaces:

ValueResolver<T>

public class CachingValueResolverWrapper<T>
extends Object
implements ValueResolver<T>

A wrapper for an instance of ValueResolver in which the delegate is only invoked once and the obtained value is cached. This is useful in cases in which its expensive for the delegate to resolve the value.

Care should be taken when using this class to wrap resolvers which isDynamic() method return true. Since this wrapper will cache the result of the first invocation, the resolver's dynamism is in effect neutralized.

This class is thread safe. Many threads can invoke the resolve(MuleEvent) method and the underlying delegate is still guaranteed to be invoked only once and the return value to be consistent with that of the thread which first got access to it.

This class can also be used without performance considerations since it's optimized to only perform thread contention until a value is cached. From then on, no locks will be used while remaining thread safe

Since:

3.7.0

Constructor Summary

Constructors

Constructor and Description
CachingValueResolverWrapper(ValueResolver<T> delegate)

Method Summary

Methods

Modifier and Type	Method and Description
boolean	isDynamic() returns false since the same value will be returned in each invocation
T	resolve(MuleEvent event) Upon first invocation, the value is resolved using the delegate and the return value is stored.

Methods inherited from class java.lang.Object

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

Constructor Detail

CachingValueResolverWrapper

public CachingValueResolverWrapper(ValueResolver<T> delegate)

Method Detail

resolve

public T resolve(MuleEvent event)
          throws MuleException

Upon first invocation, the value is resolved using the delegate and the return value is stored. From then on, the stored value is always returned

Specified by:

resolve in interface ValueResolver<T>

Parameters:

event - a MuleEvent

Returns:

the result of the first invocation

Throws:

Exception

MuleException - if the resolution of the value fails

isDynamic

public boolean isDynamic()

returns false since the same value will be returned in each invocation

Specified by:

isDynamic in interface ValueResolver<T>

Returns:

whether this resolve is dynamic