State.java

/*
 * Copyright (c) 2013 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.drivemarks.web.models;

import java.util.List;

import com.google.gson.Gson;
import com.google.gson.GsonBuilder;

/**
 * An object representing the state parameter passed into this application
 * from the Drive UI integration (i.e. Open With or Create New). Required
 * for Gson to deserialize the JSON into POJO form.
 *
 */
public class State {
  /**
   * Action intended by the state.
   */
  public String action;

  /**
   * IDs of files on which to take action.
   */
  public List<String> ids;

  /**
   * Parent ID related to the given action.
   */
  public String parentId;

  /**
   * Empty constructor required by Gson.
   */
  public State() {}

  /**
   * Create a new State given its JSON representation.
   *
   * @param json Serialized representation of a State.
   */
  public State(String json) {
    // TODO: reuse an existing gson object.
    GsonBuilder builder = new GsonBuilder();
    Gson gson = builder.create();
    State other = gson.fromJson(json, State.class);
    this.action = other.action;
    this.ids = other.ids;
    this.parentId = other.parentId;
  }
  
  public String firstFileId() {
    if (ids != null && ids.size() > 0) {
      return ids.get(0);
    }
    return null;
  }
}