/*
 *    Copyright 2009-2011 The MyBatis Team
 *
 *    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.apache.ibatis.cache.impl;


import org.apache.ibatis.cache.Cache;
import org.apache.ibatis.cache.CacheException;

import java.util.HashMap;
import java.util.Map;
import java.util.concurrent.locks.ReadWriteLock;
import java.util.concurrent.locks.ReentrantReadWriteLock;

public class PerpetualCache implements Cache {

  private String id;

  private Map<Object, Object> cache = new HashMap<Object, Object>();

  private ReadWriteLock readWriteLock = new ReentrantReadWriteLock();

  public PerpetualCache(String id) {
    this.id = id;
  }

  public String getId() {
    return id;
  }

  public int getSize() {
    return cache.size();
  }

  public void putObject(Object key, Object value) {
    cache.put(key, value);
  }

  public Object getObject(Object key) {
    return cache.get(key);
  }

  public Object removeObject(Object key) {
    return cache.remove(key);
  }

  public void clear() {
    cache.clear();
  }

  public ReadWriteLock getReadWriteLock() {
    return readWriteLock;
  }

  public boolean equals(Object o) {
    if (getId() == null) throw new CacheException("Cache instances require an ID.");
    if (this == o) return true;
    if (!(o instanceof Cache)) return false;

    Cache otherCache = (Cache) o;
    return getId().equals(otherCache.getId());
  }

  public int hashCode() {
    if (getId() == null) throw new CacheException("Cache instances require an ID.");
    return getId().hashCode();
  }

}
