/*

 * Copyright (c) 1996, 2016, 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 {@code StringWriter} has no effect. The methods in this class

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

 * {@code IOException}.

 *

 * @author      Mark Reinhold

 * @since       1.1

 */

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 {@code char} values that will fit into this buffer

     *        before it is automatically expanded

     *

     * @throws IllegalArgumentException

     *         If {@code initialSize} 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

     *

     * @throws  IndexOutOfBoundsException

     *          If {@code off} is negative, or {@code len} is negative,

     *          or {@code off + len} is negative or greater than the length

     *          of the given array

     */

    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

     *

     * @throws  IndexOutOfBoundsException

     *          If {@code off} is negative, or {@code len} is negative,

     *          or {@code off + len} is negative or greater than the length

     *          of the given string

     */

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

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

    }

    /**

     * Appends the specified character sequence to this writer.

     *

     * <p> An invocation of this method of the form {@code out.append(csq)}

     * behaves in exactly the same way as the invocation

     *

     * <pre>

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

     *

     * <p> Depending on the specification of {@code toString} for the

     * character sequence {@code csq}, the entire sequence may not be

     * appended. For instance, invoking the {@code toString} 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 {@code csq} is

     *         {@code null}, then the four characters {@code "null"} are

     *         appended to this writer.

     *

     * @return  This writer

     *

     * @since  1.5

     */

    public StringWriter append(CharSequence csq) {

        write(String.valueOf(csq));

        return this;

    }

    /**

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

     *

     * <p> An invocation of this method of the form

     * {@code out.append(csq, start, end)} when {@code csq}

     * is not {@code null}, behaves in

     * exactly the same way as the invocation

     *

     * <pre>{@code

     *     out.write(csq.subSequence(start, end).toString())

     * }</pre>

     *

     * @param  csq

     *         The character sequence from which a subsequence will be

     *         appended.  If {@code csq} is {@code null}, then characters

     *         will be appended as if {@code csq} contained the four

     *         characters {@code "null"}.

     *

     * @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 {@code start} or {@code end} are negative, {@code start}

     *          is greater than {@code end}, or {@code end} is greater than

     *          {@code csq.length()}

     *

     * @since  1.5

     */

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

        if (csq == null) csq = "null";

        return append(csq.subSequence(start, end));

    }

    /**

     * Appends the specified character to this writer.

     *

     * <p> An invocation of this method of the form {@code out.append(c)}

     * 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 {@code StringWriter} has no effect. The methods in this

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

     * an {@code IOException}.

     */

    public void close() throws IOException {

    }

}