/*
    * Copyright 2016 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.codec.redis;
  
  import io.netty.util.AbstractReferenceCounted;
  import io.netty.util.ReferenceCountUtil;
  import io.netty.util.internal.ObjectUtil;
  import io.netty.util.internal.StringUtil;
  import io.netty.util.internal.UnstableApi;
  
  import java.util.Collections;
  import java.util.List;
  
  /**
   * Arrays of <a href="https://redis.io/topics/protocol">RESP</a>.
   */
  @UnstableApi
  public class ArrayRedisMessage extends AbstractReferenceCounted implements RedisMessage {
  
      private final List<RedisMessage> children;
  
      private ArrayRedisMessage() {
          children = Collections.emptyList();
      }
  
      /**
       * Creates a {@link ArrayRedisMessage} for the given {@code content}.
       *
       * @param children the children.
       */
      public ArrayRedisMessage(List<RedisMessage> children) {
          // do not retain here. children are already retained when created.
          this.children = ObjectUtil.checkNotNull(children, "children");
      }
  
      /**
       * Get children of this Arrays. It can be null or empty.
       *
       * @return list of {@link RedisMessage}s.
       */
      public final List<RedisMessage> children() {
          return children;
      }
  
      /**
       * Returns whether the content of this message is {@code null}.
       *
       * @return indicates whether the content of this message is {@code null}.
       */
      public boolean isNull() {
          return false;
      }
  
      @Override
      protected void deallocate() {
          for (RedisMessage msg : children) {
              ReferenceCountUtil.release(msg);
          }
      }
  
      @Override
      public ArrayRedisMessage touch(Object hint) {
          for (RedisMessage msg : children) {
              ReferenceCountUtil.touch(msg);
          }
          return this;
      }
  
      @Override
      public String toString() {
          return new StringBuilder(StringUtil.simpleClassName(this))
                  .append('[')
                  .append("children=")
                  .append(children.size())
                  .append(']').toString();
      }
  
      /**
       * A predefined null array instance for {@link ArrayRedisMessage}.
       */
      public static final ArrayRedisMessage NULL_INSTANCE = new ArrayRedisMessage() {
          @Override
          public boolean isNull() {
              return true;
          }
  
         @Override
         public ArrayRedisMessage retain() {
             return this;
         }
 
         @Override
         public ArrayRedisMessage retain(int increment) {
             return this;
         }
 
         @Override
         public ArrayRedisMessage touch() {
             return this;
         }
 
         @Override
         public ArrayRedisMessage touch(Object hint) {
             return this;
         }
 
         @Override
         public boolean release() {
             return false;
         }
 
         @Override
         public boolean release(int decrement) {
             return false;
         }
 
         @Override
         public String toString() {
             return "NullArrayRedisMessage";
         }
     };
 
     /**
      * A predefined empty array instance for {@link ArrayRedisMessage}.
      */
     public static final ArrayRedisMessage EMPTY_INSTANCE = new ArrayRedisMessage() {
 
         @Override
         public ArrayRedisMessage retain() {
             return this;
         }
 
         @Override
         public ArrayRedisMessage retain(int increment) {
             return this;
         }
 
         @Override
         public ArrayRedisMessage touch() {
             return this;
         }
 
         @Override
         public ArrayRedisMessage touch(Object hint) {
             return this;
         }
 
         @Override
         public boolean release() {
             return false;
         }
 
         @Override
         public boolean release(int decrement) {
             return false;
         }
 
         @Override
         public String toString() {
             return "EmptyArrayRedisMessage";
         }
     };
 
 }