/*
 * 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.
 Closing a StringWriter has no effect. The methods in this class can be called after the stream has been closed without generating an IOException. 
Author:
     Mark Reinhold
Since:
      1.1/**
 * 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.
/**
     * 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.
Params:
initialSize –  The number of char values that will fit into this buffer before it is automatically expanded
Throws:
IllegalArgumentException –  If initialSize is negative/**
     * 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.
/**
     * Write a single character.
     */
    public void write(int c) {
        buf.append((char) c);
    }

    
Write a portion of an array of characters.
Params:
cbuf –  Array of characters
off –   Offset from which to start writing characters
len –   Number of characters to write
Throws:
IndexOutOfBoundsException –  If off is negative, or len is negative, or off + len is negative or greater than the length of the given array/**
     * 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.
/**
     * Write a string.
     */
    public void write(String str) {
        buf.append(str);
    }

    
Write a portion of a string.
Params:
str –  String to be written
off –  Offset from which to start writing characters
len –  Number of characters to write
Throws:
IndexOutOfBoundsException –  If off is negative, or len is negative, or off + len is negative or greater than the length of the given string/**
     * 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.
 An invocation of this method of the form out.append(csq) behaves in exactly the same way as the invocation 
    out.write(csq.toString()) 
 Depending on the specification of toString for the character sequence csq, the entire sequence may not be appended. For instance, invoking the toString method of a character buffer will return a subsequence whose content depends upon the buffer's position and limit. 
Params:
csq –  The character sequence to append. If csq is null, then the four characters "null" are appended to this writer.
Returns:
 This writer
Since:
 1.5/**
     * 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.
 An invocation of this method of the form out.append(csq, start, end) when csq is not null, behaves in exactly the same way as the invocation 

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

Params:
csq –  The character sequence from which a subsequence will be appended. If csq is null, then characters will be appended as if csq contained the four characters "null".
start – 
        The index of the first character in the subsequence
end – 
        The index of the character following the last character in the
        subsequence
Throws:
IndexOutOfBoundsException –  If start or end are negative, start is greater than end, or end is greater than csq.length()
Returns:
 This writer
Since:
 1.5/**
     * 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.
 An invocation of this method of the form out.append(c) behaves in exactly the same way as the invocation 
    out.write(c) 
Params:
c – 
        The 16-bit character to append
Returns:
 This writer
Since:
1.5/**
     * 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.
/**
     * Return the buffer's current value as a string.
     */
    public String toString() {
        return buf.toString();
    }

    
Return the string buffer itself.
Returns:
StringBuffer holding the current buffer value./**
     * Return the string buffer itself.
     *
     * @return StringBuffer holding the current buffer value.
     */
    public StringBuffer getBuffer() {
        return buf;
    }

    
Flush the stream.
/**
     * Flush the stream.
     */
    public void flush() {
    }

    
Closing a StringWriter has no effect. The methods in this class can be called after the stream has been closed without generating an IOException. /**
     * 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 {
    }

}