/*
    * ====================================================================
    * Licensed to the Apache Software Foundation (ASF) under one
    * or more contributor license agreements.  See the NOTICE file
    * distributed with this work for additional information
    * regarding copyright ownership.  The ASF 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
   *
   *   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.
   * ====================================================================
   *
   * This software consists of voluntary contributions made by many
   * individuals on behalf of the Apache Software Foundation.  For more
   * information on the Apache Software Foundation, please see
   * <http://www.apache.org/>.
   *
   */
  package org.apache.http.nio.protocol;
  
  import java.io.IOException;
  
  import org.apache.http.HttpEntity;
  import org.apache.http.HttpEntityEnclosingRequest;
  import org.apache.http.HttpHost;
  import org.apache.http.HttpRequest;
  import org.apache.http.nio.ContentEncoder;
  import org.apache.http.nio.IOControl;
  import org.apache.http.nio.entity.EntityAsyncContentProducer;
  import org.apache.http.nio.entity.HttpAsyncContentProducer;
  import org.apache.http.protocol.HttpContext;
  import org.apache.http.util.Args;
  
  /**
   * Basic implementation of {@link HttpAsyncRequestProducer}. The producer
   * can make use of the {@link HttpAsyncContentProducer} interface to
   * efficiently stream out message content to the underlying non-blocking HTTP
   * connection, if it is implemented by the enclosed {@link HttpEntity}.
   *
   * @see HttpAsyncContentProducer
   *
   * @since 4.2
   */
  public class BasicAsyncRequestProducer implements HttpAsyncRequestProducer {
  
      private final HttpHost target;
      private final HttpRequest request;
      private final HttpAsyncContentProducer producer;
  
      /**
       * Creates a producer that can be used to transmit the given request
       * message. The given content producer will be used to stream out message
       * content. Please note that the request message is expected to enclose
       * an {@link HttpEntity} whose properties are consistent with the behavior
       * of the content producer.
       *
       * @param target target host.
       * @param request request message.
       * @param producer request content producer.
       */
      protected BasicAsyncRequestProducer(
              final HttpHost target,
              final HttpEntityEnclosingRequest request,
              final HttpAsyncContentProducer producer) {
          super();
          Args.notNull(target, "HTTP host");
          Args.notNull(request, "HTTP request");
          Args.notNull(producer, "HTTP content producer");
          this.target = target;
          this.request = request;
          this.producer = producer;
      }
  
      /**
       * Creates a producer that can be used to transmit the given request
       * message. If the request message encloses an {@link HttpEntity}
       * it is also expected to implement {@link HttpAsyncContentProducer}.
       *
       * @param target target host.
       * @param request request message.
       */
      public BasicAsyncRequestProducer(final HttpHost target, final HttpRequest request) {
          Args.notNull(target, "HTTP host");
          Args.notNull(request, "HTTP request");
          this.target = target;
          this.request = request;
          if (request instanceof HttpEntityEnclosingRequest) {
              final HttpEntity entity = ((HttpEntityEnclosingRequest) request).getEntity();
              if (entity != null) {
                  if (entity instanceof HttpAsyncContentProducer) {
                      this.producer = (HttpAsyncContentProducer) entity;
                 } else {
                     this.producer = new EntityAsyncContentProducer(entity);
                 }
             } else {
                 this.producer = null;
             }
         } else {
             this.producer = null;
         }
     }
 
     @Override
     public HttpRequest generateRequest() {
         return this.request;
     }
 
     @Override
     public HttpHost getTarget() {
         return this.target;
     }
 
     @Override
     public void produceContent(
             final ContentEncoder encoder, final IOControl ioControl) throws IOException {
         if (this.producer != null) {
             this.producer.produceContent(encoder, ioControl);
             if (encoder.isCompleted()) {
                 this.producer.close();
             }
         }
     }
 
     @Override
     public void requestCompleted(final HttpContext context) {
     }
 
     @Override
     public void failed(final Exception ex) {
     }
 
     @Override
     public boolean isRepeatable() {
         return this.producer == null || this.producer.isRepeatable();
     }
 
     @Override
     public void resetRequest() throws IOException {
         if (this.producer != null) {
             this.producer.close();
         }
     }
 
     @Override
     public void close() throws IOException {
         if (this.producer != null) {
             this.producer.close();
         }
     }
 
     @Override
     public String toString() {
         final StringBuilder sb = new StringBuilder();
         sb.append(this.target);
         sb.append(' ');
         sb.append(this.request);
         if (this.producer != null) {
             sb.append(' ');
             sb.append(this.producer);
         }
         return sb.toString();
     }
 
 }