/*
 * 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
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 */

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 {
 }

}