/*
 * Copyright (c) 1994, 2008, 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.lang;


/**
 * A thread-safe, mutable sequence of characters.
 * A string buffer is like a {@link String}, but can be modified. At any
 * point in time it contains some particular sequence of characters, but
 * the length and content of the sequence can be changed through certain
 * method calls.
 * <p>
 * String buffers are safe for use by multiple threads. The methods
 * are synchronized where necessary so that all the operations on any
 * particular instance behave as if they occur in some serial order
 * that is consistent with the order of the method calls made by each of
 * the individual threads involved.
 * <p>
 * The principal operations on a <code>StringBuffer</code> are the
 * <code>append</code> and <code>insert</code> methods, which are
 * overloaded so as to accept data of any type. Each effectively
 * converts a given datum to a string and then appends or inserts the
 * characters of that string to the string buffer. The
 * <code>append</code> method always adds these characters at the end
 * of the buffer; the <code>insert</code> method adds the characters at
 * a specified point.
 * <p>
 * For example, if <code>z</code> refers to a string buffer object
 * whose current contents are "<code>start</code>", then
 * the method call <code>z.append("le")</code> would cause the string
 * buffer to contain "<code>startle</code>", whereas
 * <code>z.insert(4, "le")</code> would alter the string buffer to
 * contain "<code>starlet</code>".
 * <p>
 * In general, if sb refers to an instance of a <code>StringBuffer</code>,
 * then <code>sb.append(x)</code> has the same effect as
 * <code>sb.insert(sb.length(),&nbsp;x)</code>.
 * <p>
 * Whenever an operation occurs involving a source sequence (such as
 * appending or inserting from a source sequence) this class synchronizes
 * only on the string buffer performing the operation, not on the source.
 * <p>
 * Every string buffer has a capacity. As long as the length of the
 * character sequence contained in the string buffer does not exceed
 * the capacity, it is not necessary to allocate a new internal
 * buffer array. If the internal buffer overflows, it is
 * automatically made larger.
 *
 * As of  release JDK 5, this class has been supplemented with an equivalent
 * class designed for use by a single thread, {@link StringBuilder}.  The
 * <tt>StringBuilder</tt> class should generally be used in preference to
 * this one, as it supports all of the same operations but it is faster, as
 * it performs no synchronization.
 *
 * @author      Arthur van Hoff
 * @see     java.lang.StringBuilder
 * @see     java.lang.String
 * @since   JDK1.0
 */
public final class StringBuffer
		extends AbstractStringBuilder
		implements java.io.Serializable, CharSequence
{

	/** use serialVersionUID from JDK 1.0.2 for interoperability */
	static final long serialVersionUID = 3388685877147921107L;

	/**
	 * Constructs a string buffer with no characters in it and an
	 * initial capacity of 16 characters.
	 */
	public StringBuffer() {
		super(16);
	}

	/**
	 * Constructs a string buffer with no characters in it and
	 * the specified initial capacity.
	 *
	 * @param      capacity  the initial capacity.
	 * @exception  NegativeArraySizeException  if the <code>capacity</code>
	 *               argument is less than <code>0</code>.
	 */
	public StringBuffer(int capacity) {
		super(capacity);
	}

	/**
	 * Constructs a string buffer initialized to the contents of the
	 * specified string. The initial capacity of the string buffer is
	 * <code>16</code> plus the length of the string argument.
	 *
	 * @param   str   the initial contents of the buffer.
	 * @exception NullPointerException if <code>str</code> is <code>null</code>
	 */
	public StringBuffer(String str) {
		super(str.length() + 16);
		append(str);
	}

	/**
	 * Constructs a string buffer that contains the same characters
	 * as the specified <code>CharSequence</code>. The initial capacity of
	 * the string buffer is <code>16</code> plus the length of the
	 * <code>CharSequence</code> argument.
	 * <p>
	 * If the length of the specified <code>CharSequence</code> is
	 * less than or equal to zero, then an empty buffer of capacity
	 * <code>16</code> is returned.
	 *
	 * @param      seq   the sequence to copy.
	 * @exception NullPointerException if <code>seq</code> is <code>null</code>
	 * @since 1.5
	 */
	public StringBuffer(CharSequence seq) {
		this(seq.length() + 16);
		append(seq);
	}

	public synchronized int length() {
		return count;
	}

	public synchronized int capacity() {
		return value.length;
	}


	public synchronized void ensureCapacity(int minimumCapacity) {
		if (minimumCapacity > value.length) {
			expandCapacity(minimumCapacity);
		}
	}

	/**
	 * @since      1.5
	 */
	public synchronized void trimToSize() {
		super.trimToSize();
	}

	/**
	 * @throws IndexOutOfBoundsException {@inheritDoc}
	 * @see        #length()
	 */
	public synchronized void setLength(int newLength) {
		super.setLength(newLength);
	}

	/**
	 * @throws IndexOutOfBoundsException {@inheritDoc}
	 * @see        #length()
	 */
	public synchronized char charAt(int index) {
		if ((index < 0) || (index >= count))
			throw new StringIndexOutOfBoundsException(index);
		return value[index];
	}

	/**
	 * @since      1.5
	 */
	public synchronized int codePointAt(int index) {
		return super.codePointAt(index);
	}

	/**
	 * @since     1.5
	 */
	public synchronized int codePointBefore(int index) {
		return super.codePointBefore(index);
	}

	/**
	 * @since     1.5
	 */
	public synchronized int codePointCount(int beginIndex, int endIndex) {
		return super.codePointCount(beginIndex, endIndex);
	}

	/**
	 * @since     1.5
	 */
	public synchronized int offsetByCodePoints(int index, int codePointOffset) {
		return super.offsetByCodePoints(index, codePointOffset);
	}

	/**
	 * @throws NullPointerException {@inheritDoc}
	 * @throws IndexOutOfBoundsException {@inheritDoc}
	 */
	public synchronized void getChars(int srcBegin, int srcEnd, char[] dst,
									  int dstBegin)
	{
		super.getChars(srcBegin, srcEnd, dst, dstBegin);
	}

	/**
	 * @throws IndexOutOfBoundsException {@inheritDoc}
	 * @see        #length()
	 */
	public synchronized void setCharAt(int index, char ch) {
		if ((index < 0) || (index >= count))
			throw new StringIndexOutOfBoundsException(index);
		value[index] = ch;
	}

	public synchronized StringBuffer append(Object obj) {
		super.append(String.valueOf(obj));
		return this;
	}

	public synchronized StringBuffer append(String str) {
		super.append(str);
		return this;
	}

	/**
	 * Appends the specified <tt>StringBuffer</tt> to this sequence.
	 * <p>
	 * The characters of the <tt>StringBuffer</tt> argument are appended,
	 * in order, to the contents of this <tt>StringBuffer</tt>, increasing the
	 * length of this <tt>StringBuffer</tt> by the length of the argument.
	 * If <tt>sb</tt> is <tt>null</tt>, then the four characters
	 * <tt>"null"</tt> are appended to this <tt>StringBuffer</tt>.
	 * <p>
	 * Let <i>n</i> be the length of the old character sequence, the one
	 * contained in the <tt>StringBuffer</tt> just prior to execution of the
	 * <tt>append</tt> method. Then the character at index <i>k</i> in
	 * the new character sequence is equal to the character at index <i>k</i>
	 * in the old character sequence, if <i>k</i> is less than <i>n</i>;
	 * otherwise, it is equal to the character at index <i>k-n</i> in the
	 * argument <code>sb</code>.
	 * <p>
	 * This method synchronizes on <code>this</code> (the destination)
	 * object but does not synchronize on the source (<code>sb</code>).
	 *
	 * @param   sb   the <tt>StringBuffer</tt> to append.
	 * @return  a reference to this object.
	 * @since 1.4
	 */
	public synchronized StringBuffer append(StringBuffer sb) {
		super.append(sb);
		return this;
	}


	/**
	 * Appends the specified <code>CharSequence</code> to this
	 * sequence.
	 * <p>
	 * The characters of the <code>CharSequence</code> argument are appended,
	 * in order, increasing the length of this sequence by the length of the
	 * argument.
	 *
	 * <p>The result of this method is exactly the same as if it were an
	 * invocation of this.append(s, 0, s.length());
	 *
	 * <p>This method synchronizes on this (the destination)
	 * object but does not synchronize on the source (<code>s</code>).
	 *
	 * <p>If <code>s</code> is <code>null</code>, then the four characters
	 * <code>"null"</code> are appended.
	 *
	 * @param   s the <code>CharSequence</code> to append.
	 * @return  a reference to this object.
	 * @since 1.5
	 */
	public StringBuffer append(CharSequence s) {
		// Note, synchronization achieved via other invocations
		if (s == null)
			s = "null";
		if (s instanceof String)
			return this.append((String)s);
		if (s instanceof StringBuffer)
			return this.append((StringBuffer)s);
		return this.append(s, 0, s.length());
	}

	/**
	 * @throws IndexOutOfBoundsException {@inheritDoc}
	 * @since      1.5
	 */
	public synchronized StringBuffer append(CharSequence s, int start, int end)
	{
		super.append(s, start, end);
		return this;
	}

	public synchronized StringBuffer append(char[] str) {
		super.append(str);
		return this;
	}

	/**
	 * @throws IndexOutOfBoundsException {@inheritDoc}
	 */
	public synchronized StringBuffer append(char[] str, int offset, int len) {
		super.append(str, offset, len);
		return this;
	}

	public synchronized StringBuffer append(boolean b) {
		super.append(b);
		return this;
	}

	public synchronized StringBuffer append(char c) {
		super.append(c);
		return this;
	}

	public synchronized StringBuffer append(int i) {
		super.append(i);
		return this;
	}

	/**
	 * @since 1.5
	 */
	public synchronized StringBuffer appendCodePoint(int codePoint) {
		super.appendCodePoint(codePoint);
		return this;
	}

	public synchronized StringBuffer append(long lng) {
		super.append(lng);
		return this;
	}

	public synchronized StringBuffer append(float f) {
		super.append(f);
		return this;
	}

	public synchronized StringBuffer append(double d) {
		super.append(d);
		return this;
	}

	/**
	 * @throws StringIndexOutOfBoundsException {@inheritDoc}
	 * @since      1.2
	 */
	public synchronized StringBuffer delete(int start, int end) {
		super.delete(start, end);
		return this;
	}

	/**
	 * @throws StringIndexOutOfBoundsException {@inheritDoc}
	 * @since      1.2
	 */
	public synchronized StringBuffer deleteCharAt(int index) {
		super.deleteCharAt(index);
		return this;
	}

	/**
	 * @throws StringIndexOutOfBoundsException {@inheritDoc}
	 * @since      1.2
	 */
	public synchronized StringBuffer replace(int start, int end, String str) {
		super.replace(start, end, str);
		return this;
	}

	/**
	 * @throws StringIndexOutOfBoundsException {@inheritDoc}
	 * @since      1.2
	 */
	public synchronized String substring(int start) {
		return substring(start, count);
	}

	/**
	 * @throws IndexOutOfBoundsException {@inheritDoc}
	 * @since      1.4
	 */
	public synchronized CharSequence subSequence(int start, int end) {
		return super.substring(start, end);
	}

	/**
	 * @throws StringIndexOutOfBoundsException {@inheritDoc}
	 * @since      1.2
	 */
	public synchronized String substring(int start, int end) {
		return super.substring(start, end);
	}

	/**
	 * @throws StringIndexOutOfBoundsException {@inheritDoc}
	 * @since      1.2
	 */
	public synchronized StringBuffer insert(int index, char[] str, int offset,
											int len)
	{
		super.insert(index, str, offset, len);
		return this;
	}

	/**
	 * @throws StringIndexOutOfBoundsException {@inheritDoc}
	 */
	public synchronized StringBuffer insert(int offset, Object obj) {
		super.insert(offset, String.valueOf(obj));
		return this;
	}

	/**
	 * @throws StringIndexOutOfBoundsException {@inheritDoc}
	 */
	public synchronized StringBuffer insert(int offset, String str) {
		super.insert(offset, str);
		return this;
	}

	/**
	 * @throws StringIndexOutOfBoundsException {@inheritDoc}
	 */
	public synchronized StringBuffer insert(int offset, char[] str) {
		super.insert(offset, str);
		return this;
	}

	/**
	 * @throws IndexOutOfBoundsException {@inheritDoc}
	 * @since      1.5
	 */
	public StringBuffer insert(int dstOffset, CharSequence s) {
		// Note, synchronization achieved via other invocations
		if (s == null)
			s = "null";
		if (s instanceof String)
			return this.insert(dstOffset, (String)s);
		return this.insert(dstOffset, s, 0, s.length());
	}

	/**
	 * @throws IndexOutOfBoundsException {@inheritDoc}
	 * @since      1.5
	 */
	public synchronized StringBuffer insert(int dstOffset, CharSequence s,
											int start, int end)
	{
		super.insert(dstOffset, s, start, end);
		return this;
	}

	/**
	 * @throws StringIndexOutOfBoundsException {@inheritDoc}
	 */
	public StringBuffer insert(int offset, boolean b) {
		return insert(offset, String.valueOf(b));
	}

	/**
	 * @throws IndexOutOfBoundsException {@inheritDoc}
	 */
	public synchronized StringBuffer insert(int offset, char c) {
		super.insert(offset, c);
		return this;
	}

	/**
	 * @throws StringIndexOutOfBoundsException {@inheritDoc}
	 */
	public StringBuffer insert(int offset, int i) {
		return insert(offset, String.valueOf(i));
	}

	/**
	 * @throws StringIndexOutOfBoundsException {@inheritDoc}
	 */
	public StringBuffer insert(int offset, long l) {
		return insert(offset, String.valueOf(l));
	}

	/**
	 * @throws StringIndexOutOfBoundsException {@inheritDoc}
	 */
	public StringBuffer insert(int offset, float f) {
		return insert(offset, String.valueOf(f));
	}

	/**
	 * @throws StringIndexOutOfBoundsException {@inheritDoc}
	 */
	public StringBuffer insert(int offset, double d) {
		return insert(offset, String.valueOf(d));
	}

	/**
	 * @throws NullPointerException {@inheritDoc}
	 * @since      1.4
	 */
	public int indexOf(String str) {
		return indexOf(str, 0);
	}

	/**
	 * @throws NullPointerException {@inheritDoc}
	 * @since      1.4
	 */
	public synchronized int indexOf(String str, int fromIndex) {
		return String.indexOf(value, 0, count,
				str.toCharArray(), 0, str.length(), fromIndex);
	}

	/**
	 * @throws NullPointerException {@inheritDoc}
	 * @since      1.4
	 */
	public int lastIndexOf(String str) {
		// Note, synchronization achieved via other invocations
		return lastIndexOf(str, count);
	}

	/**
	 * @throws NullPointerException {@inheritDoc}
	 * @since      1.4
	 */
	public synchronized int lastIndexOf(String str, int fromIndex) {
		return String.lastIndexOf(value, 0, count,
				str.toCharArray(), 0, str.length(), fromIndex);
	}

	/**
	 * @since   JDK1.0.2
	 */
	public synchronized StringBuffer reverse() {
		super.reverse();
		return this;
	}

	public synchronized String toString() {
		return new String(value, 0, count);
	}

	/**
	 * Serializable fields for StringBuffer.
	 *
	 * @serialField value  char[]
	 *              The backing character array of this StringBuffer.
	 * @serialField count int
	 *              The number of characters in this StringBuffer.
	 * @serialField shared  boolean
	 *              A flag indicating whether the backing array is shared.
	 *              The value is ignored upon deserialization.
	 */
	/* NANITE: Reflection not supported */

	//private static final java.io.ObjectStreamField[] serialPersistentFields =
	//		{
	//				new java.io.ObjectStreamField("value", char[].class),
	//				new java.io.ObjectStreamField("count", Integer.TYPE),
	//				new java.io.ObjectStreamField("shared", Boolean.TYPE),
	//		};

	/**
	 * readObject is called to restore the state of the StringBuffer from
	 * a stream.
	 */
	private synchronized void writeObject(java.io.ObjectOutputStream s)
			throws java.io.IOException {
		java.io.ObjectOutputStream.PutField fields = s.putFields();
		fields.put("value", value);
		fields.put("count", count);
		fields.put("shared", false);
		s.writeFields();
	}

	/**
	 * readObject is called to restore the state of the StringBuffer from
	 * a stream.
	 */
	private void readObject(java.io.ObjectInputStream s)
			throws java.io.IOException, ClassNotFoundException {
		java.io.ObjectInputStream.GetField fields = s.readFields();
		value = (char[])fields.get("value", null);
		count = fields.get("count", 0);
	}
}
