code: /*
   * 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.
   */
  package org.apache.commons.io.output;
  
  import java.io.IOException;
  import java.io.OutputStream;
  
  /**
   * Closed output stream. This stream throws an exception on all attempts to
   * write something to the stream.
   * <p>
   * Typically uses of this class include testing for corner cases in methods
   * that accept an output stream and acting as a sentinel value instead of
   * a <code>null</code> output stream.
   *
   * @version $Id: ClosedOutputStream.java,v 1.1.2.1.2.1 2011/01/15 20:32:25 caniszczyk Exp $
   * @since Commons IO 1.4
   */
  public class ClosedOutputStream extends OutputStream {
      
      /**
       * A singleton.
       */
      public static final ClosedOutputStream CLOSED_OUTPUT_STREAM = new ClosedOutputStream();
  
      /**
       * Throws an {@link IOException} to indicate that the stream is closed.
       *
       * @param b ignored
       * @throws IOException always thrown
       */
      @Override
      public void write(int b) throws IOException {
          throw new IOException("write(" + b + ") failed: stream is closed");
      }
  
  }
  