/**
    *    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.decorators;
  
  import java.util.concurrent.locks.ReadWriteLock;
  
  import org.apache.ibatis.cache.Cache;
  import org.apache.ibatis.logging.Log;
  import org.apache.ibatis.logging.LogFactory;
  
  /**
   * @author Clinton Begin
   */
  public class LoggingCache implements Cache {
  
    private Log log;  
    private Cache delegate;
    protected int requests = 0;
    protected int hits = 0;
  
    public LoggingCache(Cache delegate) {
      this.delegate = delegate;
      this.log = LogFactory.getLog(getId());
    }
  
    @Override
    public String getId() {
      return delegate.getId();
    }
  
    @Override
    public int getSize() {
      return delegate.getSize();
    }
  
    @Override
    public void putObject(Object key, Object object) {
      delegate.putObject(key, object);
    }
  
    @Override
    public Object getObject(Object key) {
      requests++;
      final Object value = delegate.getObject(key);
      if (value != null) {
        hits++;
      }
      if (log.isDebugEnabled()) {
        log.debug("Cache Hit Ratio [" + getId() + "]: " + getHitRatio());
      }
      return value;
    }
  
    @Override
    public Object removeObject(Object key) {
      return delegate.removeObject(key);
    }
  
    @Override
    public void clear() {
      delegate.clear();
    }
  
    @Override
    public ReadWriteLock getReadWriteLock() {
      return null;
    }
  
    @Override
    public int hashCode() {
      return delegate.hashCode();
    }
  
    @Override
    public boolean equals(Object obj) {
      return delegate.equals(obj);
    }
  
    private double getHitRatio() {
      return (double) hits / (double) requests;
    }
  
  }