/*

 * Copyright 1996-2004 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;

/**

 * 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 {

    }

}