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/******************************************************************************
 * $URL$
 * $Id$
 ******************************************************************************
 *
 * Copyright (c) 2003-2014 The Apereo Foundation
 *
 * Licensed under the Educational Community 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://opensource.org/licenses/ecl2
 *
 * 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.sakaiproject.memory.impl;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.sakaiproject.memory.api.Cache;
import org.sakaiproject.memory.api.CacheLoader;
import org.sakaiproject.memory.api.CacheStatistics;

import java.util.HashMap;
import java.util.Map;
import java.util.Properties;
import java.util.Set;

/**
 * Contains general common implementation info related to a cache.
 *
 * @author Aaron Zeckoski (azeckoski @ unicon.net) (azeckoski @ gmail.com)
 */
public abstract class BasicCache implements Cache {
    final Log log = LogFactory.getLog(BasicCache.class);
    /**
     * the name for this cache
     */
    protected String cacheName = "cache";
    /**
     * Optional object for dealing with cache events
     */
    protected org.sakaiproject.memory.api.CacheEventListener cacheEventListener = null;
    /**
     * Optional object that will deal with loading missing entries into the cache on get()
     */
    protected CacheLoader loader = null;
    /**
     * Indicates that a cache is distributed if true
     */
    protected boolean distributed = false;

    public void setDistributed(boolean distributed) {
        this.distributed = distributed;
    }

    @Override
    public boolean isDistributed() {
        return distributed;
    }

    /**
     * Construct the Cache
     * Set the listeners and cache refreshers later
     *
     * @param name the name for this cache
     */
    public BasicCache(String name) {
        this.cacheName = name;
    }

    @Override
    public String getName() {
        return this.cacheName;
    }

    @Override
    public void registerCacheEventListener(org.sakaiproject.memory.api.CacheEventListener cacheEventListener) {
        this.cacheEventListener = cacheEventListener;
    }

    @Override
    public String getDescription() {
        return "Basic ("+getName()+")";
    }

    @Override
    public void attachLoader(CacheLoader cacheLoader) {
        this.loader = cacheLoader;
    }

    @Override
    public CacheStatistics getCacheStatistics() {
        return new CacheStatistics() {
            @Override
            public long getCacheHits() {
                return 0;
            }
            @Override
            public long getCacheMisses() {
                return 0;
            }
        };
    }

    @Override
    public Properties getProperties(boolean includeExpensiveDetails) {
        Properties p = new Properties();
        p.put("name", getName());
        p.put("class", this.getClass().getSimpleName());
        return p;
    }

    // BULK operations - KNL-1246

    @Override
    public Map getAll(Set keys) {
        HashMap map = new HashMap<>();
        if (!keys.isEmpty()) {
            for (K key : keys) {
                if (key == null) {
                    throw new NullPointerException("keys Set for getAll cannot contain nulls (but it does)");
                }
                V value = this.get(key);
                if (value != null) {
                    map.put(key, value);
                }
            }
        }
        return map;
    }

    @Override
    public void putAll(Map map) {
        if (map != null && !map.isEmpty()) {
            for (Map.Entry entry : map.entrySet()) {
                this.put(entry.getKey(), entry.getValue());
            }
        }
    }

    @Override
    public void removeAll(Set keys) {
        if (!keys.isEmpty()) {
            for (K key : keys) {
                if (key == null) {
                    throw new NullPointerException("keys Set for removeAll cannot contain nulls (but it does)");
                }
                this.remove(key);
            }
        }
    }

    /* KNL-1246
     * WARNING: removeAll() cannot be implemented correctly here
     * because we can't get the set of all keys from the Cache API methods.
     * All implementations must override removeAll() method and probably should override the others
     */
}