/*

 * Copyright 1996-2005 Sun Microsystems, Inc.  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.  Sun designates this

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

 * by Sun 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,

 * CA 95054 USA or visit www.sun.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() { }

}