com.sun.faces.util.ConcurrentCache Maven / Gradle / Ivy
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package com.sun.faces.util;
import java.util.concurrent.ExecutionException;
/**
* Defines a concurrent cache with a factory for creating new object instances.
*
* This (combined with ExpiringConcurrentCache) offers functionality similar
* to com.sun.faces.util.Cache. Two differences:
*
* 1. Cache is concrete/assumes a particular implementation. ConcurrentCache
* is abstract/allows subclasses to provide the implementation. This
* facilitates alternative implementations, such as DefaultFaceletCache's
* NoCache.
* 2. ConcurrentCache does not provide remove() as part of its contract, since
* remove behavior may be subclass-specific. For example,
* ExpiringConcurentCache automatically removes items by checking for
* expiration rather than requiring manual removes.
*
* We should consider consolidating Cache and ConcurrentCache +
* ExpiringConcurrentCache into a single class hierarchy so that we
* do not need to duplicate the JCIP scalable result cache code.
*/
public abstract class ConcurrentCache {
/**
* Factory interface for creating various cacheable objects.
*/
public interface Factory {
public V newInstance(final K arg) throws Exception;
}
/**
* Constructs this cache using the specified Factory.
* @param factory
*/
public ConcurrentCache(Factory f) {
_f = f;
}
/**
* Retrieves a value for the specified key.
* If the value is not already present in the cache, a new instance will
* be allocated using the Factory interface
*
* @param key the key the value is associated with
* @return the value for the specified key
*/
public abstract V get(final K key) throws ExecutionException;
/**
* Tests whether the cache contains a value for the specified key
* @param key key to test
* @return true if the value for the specified key is already cached, false otherwise
*/
public abstract boolean containsKey(final K key);
/**
* Retrieves a Factory instance aasociated with this cache
* @return Factory instance
*/
protected final Factory getFactory() {
return _f;
}
private final Factory _f;
}