/**
    *    Copyright 2009-2015 the original author or authors.
    *
    *    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 java.util.HashMap;
  import java.util.Map;
  import java.util.concurrent.locks.ReadWriteLock;
  
  import org.apache.ibatis.cache.Cache;
  import org.apache.ibatis.cache.CacheException;
  
  /**
   * @author Clinton Begin
   */
  public class PerpetualCache implements Cache {
  
    private String id;
  
    private Map<Object, Object> cache = new HashMap<Object, Object>();
  
    public PerpetualCache(String id) {
      this.id = id;
    }
  
    @Override
    public String getId() {
      return id;
    }
  
    @Override
    public int getSize() {
      return cache.size();
    }
  
    @Override
    public void putObject(Object key, Object value) {
      cache.put(key, value);
    }
  
    @Override
    public Object getObject(Object key) {
      return cache.get(key);
    }
  
    @Override
    public Object removeObject(Object key) {
      return cache.remove(key);
    }
  
    @Override
    public void clear() {
      cache.clear();
    }
  
    @Override
    public ReadWriteLock getReadWriteLock() {
      return null;
    }
  
    @Override
    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());
    }
  
    @Override
    public int hashCode() {
      if (getId() == null) {
        throw new CacheException("Cache instances require an ID.");
      }
      return getId().hashCode();
    }
  
  }