/**
 * 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;

import org.waveprotocol.box.server.rpc.render.view.ConversationView;
import org.waveprotocol.box.server.rpc.render.view.ParticipantsView;
import org.waveprotocol.box.server.rpc.render.view.RootThreadView;

/**
 * Implements a conversation view by delegating primitive state matters to a
 * view object, and structural state matters to a helper. The intent is that the
 * helper is a flyweight handler.
 *
 * @param <I> intrinsic implementation
 */
public abstract class AbstractConversationViewImpl<I, H extends AbstractConversationViewImpl.Helper<? super I>> // \u2620
    extends AbstractStructuredView<H, I> // \u2620
    implements ConversationView {

  /**
   * Handles structural queries on conversation views.
   *
   * @param <I> intrinsic view implementation
   */
  public interface Helper<I> {
    RootThreadView getRootThread(I impl);

    ParticipantsView getParticipants(I impl);

    void remove(I impl);
  }

  protected AbstractConversationViewImpl(H helper, I impl) {
    super(helper, impl);
  }

  //
  // Structural delegation.
  //

  @Override
  public ParticipantsView getParticipants() {
    return helper.getParticipants(impl);
  }

  @Override
  public RootThreadView getRootThread() {
    return helper.getRootThread(impl);
  }

  @Override
  public void remove() {
    helper.remove(impl);
  }
}