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;
  
  import java.io.ByteArrayInputStream;
  import java.io.IOException;
  import java.io.InputStream;
  import java.io.InputStreamReader;
  import java.io.OutputStream;
  import java.io.OutputStreamWriter;
  import java.io.Reader;
  import java.io.StringReader;
  import java.io.Writer;
  
  /**
   * This class provides static utility methods for buffered
   * copying between sources (<code>InputStream</code>, <code>Reader</code>,
   * <code>String</code> and <code>byte[]</code>) and destinations
   * (<code>OutputStream</code>, <code>Writer</code>, <code>String</code> and
   * <code>byte[]</code>).
   * <p>
   * Unless otherwise noted, these <code>copy</code> methods do <em>not</em>
   * flush or close the streams. Often doing so would require making non-portable
   * assumptions about the streams' origin and further use. This means that both
   * streams' <code>close()</code> methods must be called after copying. if one
   * omits this step, then the stream resources (sockets, file descriptors) are
   * released when the associated Stream is garbage-collected. It is not a good
   * idea to rely on this mechanism. For a good overview of the distinction
   * between "memory management" and "resource management", see
   * <a href="http://www.unixreview.com/articles/1998/9804/9804ja/ja.htm">this
   * UnixReview article</a>.
   * <p>
   * For byte-to-char methods, a <code>copy</code> variant allows the encoding
   * to be selected (otherwise the platform default is used). We would like to
   * encourage you to always specify the encoding because relying on the platform
   * default can lead to unexpected results.
   * <p
   * We don't provide special variants for the <code>copy</code> methods that
   * let you specify the buffer size because in modern VMs the impact on speed
   * seems to be minimal. We're using a default buffer size of 4 KB.
   * <p>
   * The <code>copy</code> methods use an internal buffer when copying. It is
   * therefore advisable <em>not</em> to deliberately wrap the stream arguments
   * to the <code>copy</code> methods in <code>Buffered*</code> streams. For
   * example, don't do the following:
   * <pre>
   *  copy( new BufferedInputStream( in ), new BufferedOutputStream( out ) );
   *  </pre>
   * The rationale is as follows:
   * <p>
   * Imagine that an InputStream's read() is a very expensive operation, which
   * would usually suggest wrapping in a BufferedInputStream. The
   * BufferedInputStream works by issuing infrequent
   * {@link java.io.InputStream#read(byte[] b, int off, int len)} requests on the
   * underlying InputStream, to fill an internal buffer, from which further
   * <code>read</code> requests can inexpensively get their data (until the buffer
   * runs out).
   * <p>
   * However, the <code>copy</code> methods do the same thing, keeping an
   * internal buffer, populated by
   * {@link InputStream#read(byte[] b, int off, int len)} requests. Having two
   * buffers (or three if the destination stream is also buffered) is pointless,
   * and the unnecessary buffer management hurts performance slightly (about 3%,
   * according to some simple experiments).
   * <p>
   * Behold, intrepid explorers; a map of this class:
   * <pre>
   *       Method      Input               Output          Dependency
   *       ------      -----               ------          -------
   * 1     copy        InputStream         OutputStream    (primitive)
   * 2     copy        Reader              Writer          (primitive)
   *
   * 3     copy        InputStream         Writer          2
   *
   * 4     copy        Reader              OutputStream    2
   *
   * 5     copy        String              OutputStream    2
   * 6     copy        String              Writer          (trivial)
   *
   * 7     copy        byte[]              Writer          3
   * 8     copy        byte[]              OutputStream    (trivial)
   * </pre>
   * <p>
   * Note that only the first two methods shuffle bytes; the rest use these
   * two, or (if possible) copy using native Java copy methods. As there are
   * method variants to specify the encoding, each row may
   * correspond to up to 2 methods.
   * <p>
   * Origin of code: Excalibur.
   *
   * @author Peter Donald
   * @author Jeff Turner
   * @author Matthew Hawthorne
   * @version $Id: CopyUtils.java 659817 2008-05-24 13:23:10Z niallp $
   * @deprecated Use IOUtils. Will be removed in 2.0.
   *  Methods renamed to IOUtils.write() or IOUtils.copy().
   *  Null handling behaviour changed in IOUtils (null data does not
   *  throw NullPointerException).
   */
  @Deprecated
  public class CopyUtils {
  
      /**
       * The default size of the buffer.
       */
      private static final int DEFAULT_BUFFER_SIZE = 1024 * 4;
  
      /**
       * Instances should NOT be constructed in standard programming.
       */
      public CopyUtils() { }
  
      // ----------------------------------------------------------------
      // byte[] -> OutputStream
      // ----------------------------------------------------------------
  
      /**
       * Copy bytes from a <code>byte[]</code> to an <code>OutputStream</code>.
       * @param input the byte array to read from
       * @param output the <code>OutputStream</code> to write to
       * @throws IOException In case of an I/O problem
       */
      public static void copy(byte[] input, OutputStream output)
              throws IOException {
          output.write(input);
      }
  
      // ----------------------------------------------------------------
      // byte[] -> Writer
      // ----------------------------------------------------------------
  
      /**
       * Copy and convert bytes from a <code>byte[]</code> to chars on a
       * <code>Writer</code>.
       * The platform's default encoding is used for the byte-to-char conversion.
       * @param input the byte array to read from
       * @param output the <code>Writer</code> to write to
       * @throws IOException In case of an I/O problem
       */
      public static void copy(byte[] input, Writer output)
              throws IOException {
          ByteArrayInputStream in = new ByteArrayInputStream(input);
          copy(in, output);
      }
  
  
      /**
       * Copy and convert bytes from a <code>byte[]</code> to chars on a
       * <code>Writer</code>, using the specified encoding.
       * @param input the byte array to read from
       * @param output the <code>Writer</code> to write to
       * @param encoding The name of a supported character encoding. See the
       * <a href="http://www.iana.org/assignments/character-sets">IANA
       * Charset Registry</a> for a list of valid encoding types.
       * @throws IOException In case of an I/O problem
       */
      public static void copy(
              byte[] input,
              Writer output,
              String encoding)
                  throws IOException {
          ByteArrayInputStream in = new ByteArrayInputStream(input);
          copy(in, output, encoding);
      }
  
  
      // ----------------------------------------------------------------
      // Core copy methods
      // ----------------------------------------------------------------
  
      /**
       * Copy bytes from an <code>InputStream</code> to an
       * <code>OutputStream</code>.
       * @param input the <code>InputStream</code> to read from
       * @param output the <code>OutputStream</code> to write to
       * @return the number of bytes copied
       * @throws IOException In case of an I/O problem
       */
      public static int copy(
              InputStream input,
              OutputStream output)
                  throws IOException {
          byte[] buffer = new byte[DEFAULT_BUFFER_SIZE];
          int count = 0;
          int n = 0;
          while (-1 != (n = input.read(buffer))) {
              output.write(buffer, 0, n);
              count += n;
          }
          return count;
      }
  
      // ----------------------------------------------------------------
      // Reader -> Writer
      // ----------------------------------------------------------------
  
      /**
       * Copy chars from a <code>Reader</code> to a <code>Writer</code>.
       * @param input the <code>Reader</code> to read from
       * @param output the <code>Writer</code> to write to
       * @return the number of characters copied
       * @throws IOException In case of an I/O problem
       */
      public static int copy(
              Reader input,
              Writer output)
                  throws IOException {
          char[] buffer = new char[DEFAULT_BUFFER_SIZE];
          int count = 0;
          int n = 0;
          while (-1 != (n = input.read(buffer))) {
              output.write(buffer, 0, n);
              count += n;
          }
          return count;
      }
  
      // ----------------------------------------------------------------
      // InputStream -> Writer
      // ----------------------------------------------------------------
  
      /**
       * Copy and convert bytes from an <code>InputStream</code> to chars on a
       * <code>Writer</code>.
       * The platform's default encoding is used for the byte-to-char conversion.
       * @param input the <code>InputStream</code> to read from
       * @param output the <code>Writer</code> to write to
       * @throws IOException In case of an I/O problem
       */
      public static void copy(
              InputStream input,
              Writer output)
                  throws IOException {
          InputStreamReader in = new InputStreamReader(input);
          copy(in, output);
      }
  
      /**
       * Copy and convert bytes from an <code>InputStream</code> to chars on a
       * <code>Writer</code>, using the specified encoding.
       * @param input the <code>InputStream</code> to read from
       * @param output the <code>Writer</code> to write to
       * @param encoding The name of a supported character encoding. See the
       * <a href="http://www.iana.org/assignments/character-sets">IANA
       * Charset Registry</a> for a list of valid encoding types.
       * @throws IOException In case of an I/O problem
       */
      public static void copy(
              InputStream input,
              Writer output,
              String encoding)
                  throws IOException {
          InputStreamReader in = new InputStreamReader(input, encoding);
          copy(in, output);
      }
  
  
      // ----------------------------------------------------------------
      // Reader -> OutputStream
      // ----------------------------------------------------------------
  
      /**
       * Serialize chars from a <code>Reader</code> to bytes on an
       * <code>OutputStream</code>, and flush the <code>OutputStream</code>.
       * @param input the <code>Reader</code> to read from
       * @param output the <code>OutputStream</code> to write to
       * @throws IOException In case of an I/O problem
       */
      public static void copy(
              Reader input,
              OutputStream output)
                  throws IOException {
          OutputStreamWriter out = new OutputStreamWriter(output);
          copy(input, out);
          // XXX Unless anyone is planning on rewriting OutputStreamWriter, we
          // have to flush here.
          out.flush();
      }
  
      // ----------------------------------------------------------------
      // String -> OutputStream
      // ----------------------------------------------------------------
  
      /**
       * Serialize chars from a <code>String</code> to bytes on an
       * <code>OutputStream</code>, and
       * flush the <code>OutputStream</code>.
       * @param input the <code>String</code> to read from
       * @param output the <code>OutputStream</code> to write to
       * @throws IOException In case of an I/O problem
       */
      public static void copy(
              String input,
              OutputStream output)
                  throws IOException {
          StringReader in = new StringReader(input);
          OutputStreamWriter out = new OutputStreamWriter(output);
          copy(in, out);
          // XXX Unless anyone is planning on rewriting OutputStreamWriter, we
          // have to flush here.
          out.flush();
      }
  
      // ----------------------------------------------------------------
      // String -> Writer
      // ----------------------------------------------------------------
  
      /**
       * Copy chars from a <code>String</code> to a <code>Writer</code>.
       * @param input the <code>String</code> to read from
       * @param output the <code>Writer</code> to write to
       * @throws IOException In case of an I/O problem
       */
      public static void copy(String input, Writer output)
                  throws IOException {
          output.write(input);
      }
  
  }
  