org.codehaus.cake.internal.cache.attribute.InternalCacheAttributeService Maven / Gradle / Ivy

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/*
 * Copyright 2008 Kasper Nielsen.
 * 
 * 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://cake.codehaus.org/LICENSE
 * 
 * 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 org.codehaus.cake.internal.cache.attribute;

import org.codehaus.cake.attribute.Attribute;
import org.codehaus.cake.cache.CacheEntry;
import org.codehaus.cake.cache.policy.costsize.ReplaceCostliestPolicy;
import org.codehaus.cake.cache.policy.spi.AbstractReplacementPolicy;
import org.codehaus.cake.cache.service.attribute.CacheAttributeConfiguration;

/**
 * These are various internal methods used by {@link AbstractReplacementPolicy}.
 * 
 */
public interface InternalCacheAttributeService {
    void attachToPolicy(Attribute attribute);

    /**
     * Depends on another attributes. If the user has not registered this attribute with
     * {@link CacheAttributeConfiguration#add(Attribute...)} the attribute will be silently registered.
     * 
     * For example, LFU will depend on CacheEntry.HITS. This is a non-hard dependency because if the user has not
     * already defined it, it will just be added as a secret.
     * 
     * 
     * @param attribute
     */
    void dependOnSoft(Attribute attribute);

    /**
     * Depends on another attributes. If the user has not registered this attribute with
     * {@link CacheAttributeConfiguration#add(Attribute...)} the cache will fail to startup. For example, it does not
     * make sense to use {@link ReplaceCostliestPolicy} if the user does not supply entries a {@link CacheEntry#COST}
     * attached.
     * 
     * @see #dependOnSoft(Attribute)
     */
    void dependOnHard(Attribute attribute);
}