/*
* #!
* Ontopia Engine
* #-
* Copyright (C) 2001 - 2013 The Ontopia Project
* #-
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
* !#
*/
package net.ontopia.utils;
import java.util.HashMap;
import java.util.Map;
/**
* INTERNAL: Decider that maintains a cache of decisions made on a set
* of objects. It works with any implementation of DeciderIF.</p>
*
* The cache is first checked to see if a decision has already been
* made. Otherwise a new decision is evaluated and the cache is
* updated.</p>
*/
public class CachedDecider<T> implements DeciderIF<T>, CachedIF {
protected DeciderIF<T> decider;
protected Map<T, Boolean> cache = new HashMap<T, Boolean>();
public CachedDecider(DeciderIF<T> decider) {
this.decider = decider;
}
/**
* Gets the decider that being cached.
*/
public DeciderIF<T> getDecider() {
return decider;
}
/**
* Sets the decider that is to be cached.
*/
public void setDecider(DeciderIF<T> decider) {
this.decider = decider;
}
public boolean ok(T object) {
if (object == null) return false;
if (cache.containsKey(object)) return cache.get(object).booleanValue();
boolean decision = decider.ok(object);
if (decision == true)
cache.put(object, Boolean.TRUE);
else
cache.put(object, Boolean.FALSE);
return decision;
}
public void refresh() {
cache.clear();
}
}