/*
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    * ====================================================================
    *
    *  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.conn;
  
  import java.io.IOException;
  import java.io.InputStream;
  import java.io.OutputStream;
  import java.net.SocketException;
  
  import org.apache.http.annotation.NotThreadSafe;
  
  import org.apache.http.HttpEntity;
  import org.apache.http.entity.HttpEntityWrapper;
  import org.apache.http.util.EntityUtils;
  
  /**
   * An entity that releases a {@link ManagedClientConnection connection}.
   * A {@link ManagedClientConnection} will
   * typically <i>not</i> return a managed entity, but you can replace
   * the unmanaged entity in the response with a managed one.
   *
   * @since 4.0
   */
  @NotThreadSafe
  public class BasicManagedEntity extends HttpEntityWrapper
      implements ConnectionReleaseTrigger, EofSensorWatcher {
  
      /** The connection to release. */
      protected ManagedClientConnection managedConn;
  
      /** Whether to keep the connection alive. */
      protected final boolean attemptReuse;
  
      /**
       * Creates a new managed entity that can release a connection.
       *
       * @param entity    the entity of which to wrap the content.
       *                  Note that the argument entity can no longer be used
       *                  afterwards, since the content will be taken by this
       *                  managed entity.
       * @param conn      the connection to release
       * @param reuse     whether the connection should be re-used
       */
      public BasicManagedEntity(HttpEntity entity,
                                ManagedClientConnection conn,
                                boolean reuse) {
          super(entity);
  
          if (conn == null)
              throw new IllegalArgumentException
                  ("Connection may not be null.");
  
          this.managedConn = conn;
          this.attemptReuse = reuse;
      }
  
      @Override
      public boolean isRepeatable() {
          return false;
      }
  
      @Override
      public InputStream getContent() throws IOException {
          return new EofSensorInputStream(wrappedEntity.getContent(), this);
      }
  
      private void ensureConsumed() throws IOException {
          if (managedConn == null)
              return;
  
          try {
              if (attemptReuse) {
                  // this will not trigger a callback from EofSensorInputStream
                  EntityUtils.consume(wrappedEntity);
                 managedConn.markReusable();
             } else {
                 managedConn.unmarkReusable();
             }
         } finally {
             releaseManagedConnection();
         }
     }
 
     /**
      * @deprecated (4.1) Use {@link EntityUtils#consume(HttpEntity)}
      */
     @Override
     public void consumeContent() throws IOException {
         ensureConsumed();
     }
 
     @Override
     public void writeTo(final OutputStream outstream) throws IOException {
         super.writeTo(outstream);
         ensureConsumed();
     }
 
     public void releaseConnection() throws IOException {
         ensureConsumed();
     }
 
     public void abortConnection() throws IOException {
 
         if (managedConn != null) {
             try {
                 managedConn.abortConnection();
             } finally {
                 managedConn = null;
             }
         }
     }
 
     public boolean eofDetected(InputStream wrapped) throws IOException {
         try {
             if (managedConn != null) {
                 if (attemptReuse) {
                     // there may be some cleanup required, such as
                     // reading trailers after the response body:
                     wrapped.close();
                     managedConn.markReusable();
                 } else {
                     managedConn.unmarkReusable();
                 }
             }
         } finally {
             releaseManagedConnection();
         }
         return false;
     }
 
     public boolean streamClosed(InputStream wrapped) throws IOException {
         try {
             if (managedConn != null) {
                 if (attemptReuse) {
                     boolean valid = managedConn.isOpen();
                     // this assumes that closing the stream will
                     // consume the remainder of the response body:
                     try {
                         wrapped.close();
                         managedConn.markReusable();
                     } catch (SocketException ex) {
                         if (valid) {
                             throw ex;
                         }
                     }
                 } else {
                     managedConn.unmarkReusable();
                 }
             }
         } finally {
             releaseManagedConnection();
         }
         return false;
     }
 
     public boolean streamAbort(InputStream wrapped) throws IOException {
         if (managedConn != null) {
             managedConn.abortConnection();
         }
         return false;
     }
 
     /**
      * Releases the connection gracefully.
      * The connection attribute will be nullified.
      * Subsequent invocations are no-ops.
      *
      * @throws IOException      in case of an IO problem.
      *         The connection attribute will be nullified anyway.
      */
     protected void releaseManagedConnection()
         throws IOException {
 
         if (managedConn != null) {
             try {
                 managedConn.releaseConnection();
             } finally {
                 managedConn = null;
             }
         }
     }
 
 }