Java I/O How to - Compare the contents of two Readers to determine if they are equal or not

Question

We would like to know how to compare the contents of two Readers to determine if they are equal or not.
Answer

   /*w  ww  .j a v  a  2s .c om*/

/*
 * 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.
 */

import java.io.BufferedReader;
import java.io.IOException;
import java.io.Reader;
/** * Origin of code: Apache Avalon (Excalibur)
 * 
 * @author Peter Donald
 * @author Jeff Turner
 * @author Matthew Hawthorne
 * @author Stephen Colebourne
 * @author Gareth Davis
 * @version CVS $Revision$ $Date$*/
public class Main {
  /**
   * Compare the contents of two Readers to determine if they are equal or not.
   * 
   * This method buffers the input internally using <code>BufferedReader if they are not
   * already buffered.
   * 
   * @param input1
   *            the first reader
   * @param input2
   *            the second reader
   * @return true if the content of the readers are equal or they both don't exist, false
   *         otherwise
   * @throws NullPointerException
   *             if either input is null
   * @throws IOException
   *             if an I/O error occurs
   * @since 1.1
   */
  public static boolean contentEquals(Reader input1, Reader input2) throws IOException
  {
    if (!(input1 instanceof BufferedReader))
    {
      input1 = new BufferedReader(input1);
    }
    if (!(input2 instanceof BufferedReader))
    {
      input2 = new BufferedReader(input2);
    }

    int ch = input1.read();
    while (-1 != ch)
    {
      int ch2 = input2.read();
      if (ch != ch2)
      {
        return false;
      }
      ch = input1.read();
    }

    int ch2 = input2.read();
    return (ch2 == -1);
  }
}