/*

  * Copyright (c) 1996, 2004, Oracle and/or its affiliates. All rights reserved.

  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

  *

  * This code is free software; you can redistribute it and/or modify it

  * under the terms of the GNU General Public License version 2 only, as

  * published by the Free Software Foundation.  Oracle designates this

  * particular file as subject to the "Classpath" exception as provided

  * by Oracle in the LICENSE file that accompanied this code.

  *

  * This code is distributed in the hope that it will be useful, but WITHOUT

  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

  * version 2 for more details (a copy is included in the LICENSE file that

  * accompanied this code).

  *

  * You should have received a copy of the GNU General Public License version

  * 2 along with this work; if not, write to the Free Software Foundation,

  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

  *

  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

  * or visit www.oracle.com if you need additional information or have any

  * questions.

  */

 package java.io;

 /**

  * A character stream that collects its output in a string buffer, which can

  * then be used to construct a string.

  * <p>

  * Closing a <tt>StringWriter</tt> has no effect. The methods in this class

  * can be called after the stream has been closed without generating an

  * <tt>IOException</tt>.

  *

  * @author      Mark Reinhold

  * @since       JDK1.1

  */

 public class StringWriter extends Writer {

     private StringBuffer buf;

     /**

      * Create a new string writer using the default initial string-buffer

      * size.

      */

     public StringWriter() {

         buf = new StringBuffer();

         lock = buf;

     }

     /**

      * Create a new string writer using the specified initial string-buffer

      * size.

      *

      * @param initialSize

      *        The number of <tt>char</tt> values that will fit into this buffer

      *        before it is automatically expanded

      *

      * @throws IllegalArgumentException

      *         If <tt>initialSize</tt> is negative

      */

     public StringWriter(int initialSize) {

         if (initialSize < 0) {

             throw new IllegalArgumentException("Negative buffer size");

         }

         buf = new StringBuffer(initialSize);

         lock = buf;

     }

     /**

      * Write a single character.

      */

     public void write(int c) {

         buf.append((char) c);

     }

     /**

      * Write a portion of an array of characters.

      *

      * @param  cbuf  Array of characters

      * @param  off   Offset from which to start writing characters

      * @param  len   Number of characters to write

      */

     public void write(char cbuf[], int off, int len) {

         if ((off < 0) || (off > cbuf.length) || (len < 0) ||

             ((off + len) > cbuf.length) || ((off + len) < 0)) {

             throw new IndexOutOfBoundsException();

         } else if (len == 0) {

             return;

         }

         buf.append(cbuf, off, len);

     }

     /**

      * Write a string.

      */

     public void write(String str) {

         buf.append(str);

     }

     /**

      * Write a portion of a string.

      *

      * @param  str  String to be written

      * @param  off  Offset from which to start writing characters

      * @param  len  Number of characters to write

      */

     public void write(String str, int off, int len)  {

         buf.append(str.substring(off, off + len));

     }

     /**

      * Appends the specified character sequence to this writer.

      *

      * <p> An invocation of this method of the form <tt>out.append(csq)</tt>

      * behaves in exactly the same way as the invocation

      *

      * <pre>

      *     out.write(csq.toString()) </pre>

      *

      * <p> Depending on the specification of <tt>toString</tt> for the

      * character sequence <tt>csq</tt>, the entire sequence may not be

      * appended. For instance, invoking the <tt>toString</tt> method of a

      * character buffer will return a subsequence whose content depends upon

      * the buffer's position and limit.

      *

      * @param  csq

      *         The character sequence to append.  If <tt>csq</tt> is

      *         <tt>null</tt>, then the four characters <tt>"null"</tt> are

      *         appended to this writer.

      *

      * @return  This writer

      *

      * @since  1.5

      */

     public StringWriter append(CharSequence csq) {

         if (csq == null)

             write("null");

         else

             write(csq.toString());

         return this;

     }

     /**

      * Appends a subsequence of the specified character sequence to this writer.

      *

      * <p> An invocation of this method of the form <tt>out.append(csq, start,

      * end)</tt> when <tt>csq</tt> is not <tt>null</tt>, behaves in

      * exactly the same way as the invocation

      *

      * <pre>

      *     out.write(csq.subSequence(start, end).toString()) </pre>

      *

      * @param  csq

      *         The character sequence from which a subsequence will be

      *         appended.  If <tt>csq</tt> is <tt>null</tt>, then characters

      *         will be appended as if <tt>csq</tt> contained the four

      *         characters <tt>"null"</tt>.

      *

      * @param  start

      *         The index of the first character in the subsequence

      *

      * @param  end

      *         The index of the character following the last character in the

      *         subsequence

      *

      * @return  This writer

      *

      * @throws  IndexOutOfBoundsException

      *          If <tt>start</tt> or <tt>end</tt> are negative, <tt>start</tt>

      *          is greater than <tt>end</tt>, or <tt>end</tt> is greater than

      *          <tt>csq.length()</tt>

      *

      * @since  1.5

      */

     public StringWriter append(CharSequence csq, int start, int end) {

         CharSequence cs = (csq == null ? "null" : csq);

         write(cs.subSequence(start, end).toString());

         return this;

     }

     /**

      * Appends the specified character to this writer.

      *

      * <p> An invocation of this method of the form <tt>out.append(c)</tt>

      * behaves in exactly the same way as the invocation

      *

      * <pre>

      *     out.write(c) </pre>

      *

      * @param  c

      *         The 16-bit character to append

      *

      * @return  This writer

      *

      * @since 1.5

      */

     public StringWriter append(char c) {

         write(c);

         return this;

     }

     /**

      * Return the buffer's current value as a string.

      */

     public String toString() {

         return buf.toString();

     }

     /**

      * Return the string buffer itself.

      *

      * @return StringBuffer holding the current buffer value.

      */

     public StringBuffer getBuffer() {

         return buf;

     }

     /**

      * Flush the stream.

      */

     public void flush() {

     }

     /**

      * Closing a <tt>StringWriter</tt> has no effect. The methods in this

      * class can be called after the stream has been closed without generating

      * an <tt>IOException</tt>.

      */

     public void close() throws IOException {

     }

 }