/*
    * ====================================================================
    * 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 java.io.ByteArrayInputStream;
  import java.io.ByteArrayOutputStream;
  import java.io.IOException;
  import java.io.InputStream;
  import java.io.OutputStream;
  
  import org.apache.hc.core5.annotation.Contract;
  import org.apache.hc.core5.annotation.ThreadingBehavior;
  import org.apache.hc.core5.http.ContentType;
  import org.apache.hc.core5.io.IOCallback;
  import org.apache.hc.core5.util.Args;
  
  /**
   * Entity that delegates the process of content generation to a {@link IOCallback}
   * with {@link OutputStream} as output sink.
   *
   * @since 4.0
   */
  @Contract(threading = ThreadingBehavior.IMMUTABLE_CONDITIONAL)
  public final class EntityTemplate extends AbstractHttpEntity {
  
      private final long contentLength;
      private final IOCallback<OutputStream> callback;
  
      public EntityTemplate(
              final long contentLength, final ContentType contentType, final String contentEncoding,
              final IOCallback<OutputStream> callback) {
          super(contentType, contentEncoding);
          this.contentLength = contentLength;
          this.callback = Args.notNull(callback, "I/O callback");
      }
  
      @Override
      public long getContentLength() {
          return contentLength;
      }
  
      @Override
      public InputStream getContent() throws IOException {
          final ByteArrayOutputStream buf = new ByteArrayOutputStream();
          writeTo(buf);
          return new ByteArrayInputStream(buf.toByteArray());
      }
  
      @Override
      public boolean isRepeatable() {
          return true;
      }
  
      @Override
      public void writeTo(final OutputStream outStream) throws IOException {
          Args.notNull(outStream, "Output stream");
          this.callback.execute(outStream);
      }
  
      @Override
      public boolean isStreaming() {
          return false;
      }
  
      @Override
      public void close() throws IOException {
      }
  
  }