org.onebusaway.container.cache.DefaultCacheableKeyFactory.java Source code

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Here is the source code for org.onebusaway.container.cache.DefaultCacheableKeyFactory.java

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/**
 * Copyright (C) 2011 Brian Ferris <bdferris@onebusaway.org>
 *
 * 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 org.onebusaway.container.cache;

import org.aspectj.lang.ProceedingJoinPoint;

import java.io.Serializable;
import java.util.Arrays;

/**
 * Factory for producing a {@link CacheKeyInfo} cache key from a
 * {@link ProceedingJoinPoint} method invocation. The default implementation
 * considers each argument to the method invocation and applies a
 * {@link CacheableObjectKeyFactory} to produce a {@link Serializable} key value
 * for that argument. An array of those {@link Serializable} key values are
 * composed together to make the final cache key. The
 * {@link CacheKeyInfo#isCacheRefreshIndicated()} cache refresh indicators from
 * each argument key are ORed together to produce a refresh indicator for the
 * entire method.
 * 
 * @author bdferris
 * @see Cacheable#keyFactory()
 * @see CacheableMethodKeyFactory
 * @see CacheableObjectKeyFactory
 */
public class DefaultCacheableKeyFactory implements CacheableMethodKeyFactory, Serializable {

    private static final long serialVersionUID = 1L;

    private CacheableObjectKeyFactory[] _keyFactories;

    public DefaultCacheableKeyFactory(CacheableObjectKeyFactory[] keyFactories) {
        _keyFactories = keyFactories;
    }

    public int getNumberOfObjectKeyFactories() {
        return _keyFactories.length;
    }

    public CacheableObjectKeyFactory getObjectKeyFactory(int i) {
        return _keyFactories[i];
    }

    @Override
    public CacheKeyInfo createKey(ProceedingJoinPoint point) {
        Object[] args = point.getArgs();
        if (args.length != _keyFactories.length)
            throw new IllegalArgumentException();

        // Short circuit for single argument keys
        if (args.length == 1)
            return _keyFactories[0].createKey(args[0]);

        KeyImpl keys = new KeyImpl(args.length);
        boolean refreshCache = false;
        for (int i = 0; i < args.length; i++) {
            CacheKeyInfo keyInfo = _keyFactories[i].createKey(args[i]);
            keys.set(i, keyInfo.getKey());
            refreshCache |= keyInfo.isCacheRefreshIndicated();
        }
        return new CacheKeyInfo(keys, refreshCache);
    }

    static class KeyImpl implements Serializable {

        private static final long serialVersionUID = 1L;

        private Serializable[] _keys;

        public KeyImpl(int entries) {
            _keys = new Serializable[entries];
        }

        public KeyImpl(Serializable[] keys) {
            _keys = keys;
        }

        public void set(int index, Serializable key) {
            _keys[index] = key;
        }

        @Override
        public boolean equals(Object obj) {
            if (obj == null || !(obj instanceof KeyImpl))
                return false;
            KeyImpl other = (KeyImpl) obj;
            return Arrays.equals(_keys, other._keys);
        }

        @Override
        public int hashCode() {
            return Arrays.hashCode(_keys);
        }

        @Override
        public String toString() {
            return Arrays.toString(_keys);
        }
    }

}