/*
    * ====================================================================
    * 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.hc.core5.http.nio.support;
  
  import java.io.IOException;
  
  import org.apache.hc.core5.http.HttpException;
  import org.apache.hc.core5.http.HttpResponse;
  import org.apache.hc.core5.http.HttpStatus;
  import org.apache.hc.core5.http.message.BasicHttpResponse;
  import org.apache.hc.core5.http.nio.AsyncEntityProducer;
  import org.apache.hc.core5.http.nio.AsyncPushProducer;
  import org.apache.hc.core5.http.nio.DataStreamChannel;
  import org.apache.hc.core5.http.nio.ResponseChannel;
  import org.apache.hc.core5.http.protocol.HttpContext;
  import org.apache.hc.core5.util.Args;
  
  /**
   * Basic implementation of {@link AsyncPushProducer} that produces one fixed response
   * and relies on a {@link AsyncEntityProducer} to generate response entity stream.
   *
   * @since 5.0
   */
  public class BasicPushProducer implements AsyncPushProducer {
  
      private final HttpResponse response;
      private final AsyncEntityProducer dataProducer;
  
      public BasicPushProducer(final HttpResponse response, final AsyncEntityProducer dataProducer) {
          this.response = Args.notNull(response, "Response");
          this.dataProducer = Args.notNull(dataProducer, "Entity producer");
      }
  
      public BasicPushProducer(final int code, final AsyncEntityProducer dataProducer) {
          this(new BasicHttpResponse(code), dataProducer);
      }
  
      public BasicPushProducer(final AsyncEntityProducer dataProducer) {
          this(HttpStatus.SC_OK, dataProducer);
      }
  
      @Override
      public void produceResponse(final ResponseChannel channel, final HttpContext httpContext) throws HttpException, IOException {
          channel.sendResponse(response, dataProducer, httpContext);
      }
  
      @Override
      public int available() {
          return dataProducer != null ? dataProducer.available() : 0;
      }
  
      @Override
      public void produce(final DataStreamChannel channel) throws IOException {
          if (dataProducer != null) {
              dataProducer.produce(channel);
          }
      }
  
      @Override
      public void failed(final Exception cause) {
          releaseResources();
      }
  
      @Override
      public void releaseResources() {
          if (dataProducer != null) {
              dataProducer.releaseResources();
          }
      }
  
  }