/**
 * Copyright 2010 Google Inc.
 *
 * 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.waveprotocol.box.server.rpc.render.view.impl;


/**
 * Implements a structural view by delegating primitive state matters to an
 * intrinsic view object, and structural state matters to a helper. The intent
 * is that the helper is a flyweight handler.
 *
 * @param <I> intrinsic view implementation
 * @param <H> flyweight handler
 */
public abstract class AbstractStructuredView<H, I> {

  protected final H helper;
  protected final I impl;

  public AbstractStructuredView(H helper, I impl) {
    this.helper = helper;
    this.impl = impl;
  }

  /** Reveals the intrinsic view object. */
  public final I getIntrinsic() {
    return impl;
  }

  //
  // Equality.
  //

  @Override
  public final boolean equals(Object obj) {
    if (this == obj) {
      return true;
    } else if (!(obj instanceof AbstractStructuredView<?, ?>)) {
      return false;
    } else {
      return impl.equals(((AbstractStructuredView<?, ?>) obj).impl);
    }
  }

  @Override
  public final int hashCode() {
    return 37 + 11 * impl.hashCode();
  }
}