/*
    * Copyright 2012 The Netty Project
    *
    * The Netty Project licenses this file to you 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:
    *
    *   https://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 io.netty.handler.timeout;
  
  import io.netty.channel.Channel;
  import io.netty.util.internal.ObjectUtil;
  import io.netty.util.internal.StringUtil;
  
  /**
   * A user event triggered by {@link IdleStateHandler} when a {@link Channel} is idle.
   */
  public class IdleStateEvent {
      public static final IdleStateEvent FIRST_READER_IDLE_STATE_EVENT =
              new DefaultIdleStateEvent(IdleState.READER_IDLE, true);
      public static final IdleStateEvent READER_IDLE_STATE_EVENT =
              new DefaultIdleStateEvent(IdleState.READER_IDLE, false);
      public static final IdleStateEvent FIRST_WRITER_IDLE_STATE_EVENT =
              new DefaultIdleStateEvent(IdleState.WRITER_IDLE, true);
      public static final IdleStateEvent WRITER_IDLE_STATE_EVENT =
              new DefaultIdleStateEvent(IdleState.WRITER_IDLE, false);
      public static final IdleStateEvent FIRST_ALL_IDLE_STATE_EVENT =
              new DefaultIdleStateEvent(IdleState.ALL_IDLE, true);
      public static final IdleStateEvent ALL_IDLE_STATE_EVENT =
              new DefaultIdleStateEvent(IdleState.ALL_IDLE, false);
  
      private final IdleState state;
      private final boolean first;
  
      /**
       * Constructor for sub-classes.
       *
       * @param state the {@link IdleStateEvent} which triggered the event.
       * @param first {@code true} if its the first idle event for the {@link IdleStateEvent}.
       */
      protected IdleStateEvent(IdleState state, boolean first) {
          this.state = ObjectUtil.checkNotNull(state, "state");
          this.first = first;
      }
  
      /**
       * Returns the idle state.
       */
      public IdleState state() {
          return state;
      }
  
      /**
       * Returns {@code true} if this was the first event for the {@link IdleState}
       */
      public boolean isFirst() {
          return first;
      }
  
      @Override
      public String toString() {
          return StringUtil.simpleClassName(this) + '(' + state + (first ? ", first" : "") + ')';
      }
  
      private static final class DefaultIdleStateEvent extends IdleStateEvent {
          private final String representation;
  
          DefaultIdleStateEvent(IdleState state, boolean first) {
              super(state, first);
              this.representation = "IdleStateEvent(" + state + (first ? ", first" : "") + ')';
          }
  
          @Override
          public String toString() {
              return representation;
          }
      }
  }