/*
    * ====================================================================
    * 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.io.entity;
  
  import org.apache.hc.core5.annotation.Contract;
  import org.apache.hc.core5.annotation.ThreadingBehavior;
  import org.apache.hc.core5.function.Supplier;
  import org.apache.hc.core5.http.Header;
  import org.apache.hc.core5.http.HttpEntity;
  
  import java.io.IOException;
  import java.io.InputStream;
  import java.io.OutputStream;
  import java.util.Collections;
  import java.util.List;
  import java.util.Set;
  
  /**
   * An empty entity with no content-type. This type may be used for convenience
   * in place of an empty {@link ByteArrayEntity}.
   *
   * @since 5.1
   */
  @Contract(threading = ThreadingBehavior.IMMUTABLE)
  public final class NullEntity implements HttpEntity {
  
      public static final NullEntityio/entity/NullEntity.html#NullEntity">NullEntity INSTANCE = new NullEntity();
  
      private NullEntity() {}
  
      @Override
      public boolean isRepeatable() {
          return true;
      }
  
      @Override
      public InputStream getContent() throws IOException, UnsupportedOperationException {
          return EmptyInputStream.INSTANCE;
      }
  
      @Override
      public void writeTo(final OutputStream outStream) throws IOException {}
  
      @Override
      public boolean isStreaming() {
          return false;
      }
  
      @Override
      public Supplier<List<? extends Header>> getTrailers() {
          return null;
      }
  
      @Override
      public void close() throws IOException {}
  
      @Override
      public long getContentLength() {
          return 0;
      }
  
      @Override
      public String getContentType() {
          return null;
      }
  
      @Override
      public String getContentEncoding() {
          return null;
      }
  
      @Override
      public boolean isChunked() {
          return false;
     }
 
     @Override
     public Set<String> getTrailerNames() {
         return Collections.emptySet();
     }
 }