content: /**
   * Copyright (C) 2011 The Android Open Source Project
   *
   * 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 com.android.internal.util;
  
  import android.annotation.UnsupportedAppUsage;
  import android.os.Message;
  
  /**
   * {@hide}
   *
   * The interface for implementing states in a {@link StateMachine}
   */
  public interface IState {
  
      /**
       * Returned by processMessage to indicate the the message was processed.
       */
      static final boolean HANDLED = true;
  
      /**
       * Returned by processMessage to indicate the the message was NOT processed.
       */
      static final boolean NOT_HANDLED = false;
  
      /**
       * Called when a state is entered.
       */
      void enter();
  
      /**
       * Called when a state is exited.
       */
      void exit();
  
      /**
       * Called when a message is to be processed by the
       * state machine.
       *
       * This routine is never reentered thus no synchronization
       * is needed as only one processMessage method will ever be
       * executing within a state machine at any given time. This
       * does mean that processing by this routine must be completed
       * as expeditiously as possible as no subsequent messages will
       * be processed until this routine returns.
       *
       * @param msg to process
       * @return HANDLED if processing has completed and NOT_HANDLED
       *         if the message wasn't processed.
       */
      boolean processMessage(Message msg);
  
      /**
       * Name of State for debugging purposes.
       *
       * @return name of state.
       */
      @UnsupportedAppUsage
      String getName();
  }
  