/**
 * 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 java.io.Serializable;

/**
 * Factory for producing a {@link Serializable} cache key from a and arbitrary
 * object. This default implementation just uses the {@link #toString()}
 * representation of the object as the cache key.
 * 
 * @author bdferris
 * @see CacheableObjectKeyFactory
 * @see DefaultCacheableKeyFactory
 */
public class DefaultCacheableObjectKeyFactory implements
    CacheableObjectKeyFactory, Serializable {

  private static final long serialVersionUID = 1L;

  private boolean _cacheRefreshCheck = false;

  /**
   * Set to true if we should check the object value to indicate a cache
   * refresh. A cache refresh will be flagged if the object value is equal to
   * {@link Boolean#TRUE}.
   * 
   * @param cacheRefreshCheck true if the object argument should be examined to
   *          flag a cache refresh
   */
  public void setCacheRefreshCheck(boolean cacheRefreshCheck) {
    _cacheRefreshCheck = cacheRefreshCheck;
  }

  public boolean isCacheRefreshCheck() {
    return _cacheRefreshCheck;
  }

  public CacheKeyInfo createKey(Object object) {

    if (_cacheRefreshCheck) {

      boolean refreshCache = Boolean.TRUE.equals(object);

      /**
       * We short-circuit the cache key to Boolean.FALSE, no matter the actual
       * key value so that the resulting cache key will be the same whether a
       * refresh has been requested or not
       */
      return new CacheKeyInfo(Boolean.FALSE, refreshCache);
    }

    if (object != null) {
      if (object instanceof Serializable)
        return new CacheKeyInfo((Serializable) object, false);
      return new CacheKeyInfo(object.toString(), false);
    }

    return new CacheKeyInfo(null, false);
  }
}