content: /*
   * Copyright (c) 1996, 2005, 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;
  
  import java.util.Arrays;
  
  /**
   * This class implements a character buffer that can be used as an Writer.
   * The buffer automatically grows when data is written to the stream.  The data
   * can be retrieved using toCharArray() and toString().
   * <P>
   * Note: Invoking close() on this class has no effect, and methods
   * of this class can be called after the stream has closed
   * without generating an IOException.
   *
   * @author      Herb Jellinek
   * @since       JDK1.1
   */
  public
  class CharArrayWriter extends Writer {
      /**
       * The buffer where data is stored.
       */
      protected char buf[];
  
      /**
       * The number of chars in the buffer.
       */
      protected int count;
  
      /**
       * Creates a new CharArrayWriter.
       */
      public CharArrayWriter() {
          this(32);
      }
  
      /**
       * Creates a new CharArrayWriter with the specified initial size.
       *
       * @param initialSize  an int specifying the initial buffer size.
       * @exception IllegalArgumentException if initialSize is negative
       */
      public CharArrayWriter(int initialSize) {
          if (initialSize < 0) {
              throw new IllegalArgumentException("Negative initial size: "
                                                 + initialSize);
          }
          buf = new char[initialSize];
      }
  
      /**
       * Writes a character to the buffer.
       */
      public void write(int c) {
          synchronized (lock) {
              int newcount = count + 1;
              if (newcount > buf.length) {
                  buf = Arrays.copyOf(buf, Math.max(buf.length << 1, newcount));
              }
              buf[count] = (char)c;
              count = newcount;
          }
      }
  
      /**
       * Writes characters to the buffer.
       * @param c the data to be written
       * @param off       the start offset in the data
       * @param len       the number of chars that are written
       */
      public void write(char c[], int off, int len) {
          if ((off < 0) || (off > c.length) || (len < 0) ||
              ((off + len) > c.length) || ((off + len) < 0)) {
              throw new IndexOutOfBoundsException();
          } else if (len == 0) {
              return;
          }
          synchronized (lock) {
              int newcount = count + len;
              if (newcount > buf.length) {
                  buf = Arrays.copyOf(buf, Math.max(buf.length << 1, newcount));
              }
              System.arraycopy(c, off, buf, count, len);
              count = newcount;
          }
      }
  
      /**
       * Write a portion of a string to the buffer.
       * @param  str  String to be written from
       * @param  off  Offset from which to start reading characters
       * @param  len  Number of characters to be written
       */
      public void write(String str, int off, int len) {
          synchronized (lock) {
              int newcount = count + len;
              if (newcount > buf.length) {
                  buf = Arrays.copyOf(buf, Math.max(buf.length << 1, newcount));
              }
              str.getChars(off, off + len, buf, count);
              count = newcount;
          }
      }
  
      /**
       * Writes the contents of the buffer to another character stream.
       *
       * @param out       the output stream to write to
       * @throws IOException If an I/O error occurs.
       */
      public void writeTo(Writer out) throws IOException {
          synchronized (lock) {
              out.write(buf, 0, count);
          }
      }
  
      /**
       * 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 CharArrayWriter append(CharSequence csq) {
          String s = (csq == null ? "null" : csq.toString());
          write(s, 0, s.length());
          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 CharArrayWriter append(CharSequence csq, int start, int end) {
          String s = (csq == null ? "null" : csq).subSequence(start, end).toString();
          write(s, 0, s.length());
          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 CharArrayWriter append(char c) {
          write(c);
          return this;
      }
  
      /**
       * Resets the buffer so that you can use it again without
       * throwing away the already allocated buffer.
       */
      public void reset() {
          count = 0;
      }
  
      /**
       * Returns a copy of the input data.
       *
       * @return an array of chars copied from the input data.
       */
      public char toCharArray()[] {
          synchronized (lock) {
              return Arrays.copyOf(buf, count);
          }
      }
  
      /**
       * Returns the current size of the buffer.
       *
       * @return an int representing the current size of the buffer.
       */
      public int size() {
          return count;
      }
  
      /**
       * Converts input data to a string.
       * @return the string.
       */
      public String toString() {
          synchronized (lock) {
              return new String(buf, 0, count);
          }
      }
  
      /**
       * Flush the stream.
       */
      public void flush() { }
  
      /**
       * Close the stream.  This method does not release the buffer, since its
       * contents might still be required. Note: Invoking this method in this class
       * will have no effect.
       */
      public void close() { }
  
  }
  