/*

 * 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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 * questions.

 */

package java.lang;

/**

 * A mutable sequence of characters.  This class provides an API compatible

 * with <code>StringBuffer</code>, but with no guarantee of synchronization.

 * This class is designed for use as a drop-in replacement for

 * <code>StringBuffer</code> in places where the string buffer was being

 * used by a single thread (as is generally the case).   Where possible,

 * it is recommended that this class be used in preference to

 * <code>StringBuffer</code> as it will be faster under most implementations.

 *

 * <p>The principal operations on a <code>StringBuilder</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 builder. The

 * <code>append</code> method always adds these characters at the end

 * of the builder; the <code>insert</code> method adds the characters at

 * a specified point.

 * <p>

 * For example, if <code>z</code> refers to a string builder object

 * whose current contents are "<code>start</code>", then

 * the method call <code>z.append("le")</code> would cause the string

 * builder to contain "<code>startle</code>", whereas

 * <code>z.insert(4, "le")</code> would alter the string builder to

 * contain "<code>starlet</code>".

 * <p>

 * In general, if sb refers to an instance of a <code>StringBuilder</code>,

 * then <code>sb.append(x)</code> has the same effect as

 * <code>sb.insert(sb.length(),&nbsp;x)</code>.

 *

 * Every string builder has a capacity. As long as the length of the

 * character sequence contained in the string builder does not exceed

 * the capacity, it is not necessary to allocate a new internal

 * buffer. If the internal buffer overflows, it is automatically made larger.

 *

 * <p>Instances of <code>StringBuilder</code> are not safe for

 * use by multiple threads. If such synchronization is required then it is

 * recommended that {@link java.lang.StringBuffer} be used.

 *

 * @author      Michael McCloskey

 * @see         java.lang.StringBuffer

 * @see         java.lang.String

 * @since       1.5

 */

public final class StringBuilder

    extends AbstractStringBuilder

    implements java.io.Serializable, CharSequence

{

    /** use serialVersionUID for interoperability */

    static final long serialVersionUID = 4383685877147921099L;

    /**

     * Constructs a string builder with no characters in it and an

     * initial capacity of 16 characters.

     */

    public StringBuilder() {

        super(16);

    }

    /**

     * Constructs a string builder with no characters in it and an

     * initial capacity specified by the <code>capacity</code> argument.

     *

     * @param      capacity  the initial capacity.

     * @throws     NegativeArraySizeException  if the <code>capacity</code>

     *               argument is less than <code>0</code>.

     */

    public StringBuilder(int capacity) {

        super(capacity);

    }

    /**

     * Constructs a string builder initialized to the contents of the

     * specified string. The initial capacity of the string builder is

     * <code>16</code> plus the length of the string argument.

     *

     * @param   str   the initial contents of the buffer.

     * @throws    NullPointerException if <code>str</code> is <code>null</code>

     */

    public StringBuilder(String str) {

        super(str.length() + 16);

        append(str);

    }

    /**

     * Constructs a string builder that contains the same characters

     * as the specified <code>CharSequence</code>. The initial capacity of

     * the string builder is <code>16</code> plus the length of the

     * <code>CharSequence</code> argument.

     *

     * @param      seq   the sequence to copy.

     * @throws    NullPointerException if <code>seq</code> is <code>null</code>

     */

    public StringBuilder(CharSequence seq) {

        this(seq.length() + 16);

        append(seq);

    }

    @Override

    public StringBuilder append(Object obj) {

        return append(String.valueOf(obj));

    }

    @Override

    public StringBuilder 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 this sequence, increasing the

     * length of this sequence 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 sequence.

     * <p>

     * Let <i>n</i> be the length of this character sequence 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>.

     *

     * @param   sb   the <tt>StringBuffer</tt> to append.

     * @return  a reference to this object.

     */

    public StringBuilder append(StringBuffer sb) {

        super.append(sb);

        return this;

    }

    @Override

    public StringBuilder append(CharSequence s) {

        super.append(s);

        return this;

    }

    /**

     * @throws     IndexOutOfBoundsException {@inheritDoc}

     */

    @Override

    public StringBuilder append(CharSequence s, int start, int end) {

        super.append(s, start, end);

        return this;

    }

    @Override

    public StringBuilder append(char[] str) {

        super.append(str);

        return this;

    }

    /**

     * @throws IndexOutOfBoundsException {@inheritDoc}

     */

    @Override

    public StringBuilder append(char[] str, int offset, int len) {

        super.append(str, offset, len);

        return this;

    }

    @Override

    public StringBuilder append(boolean b) {

        super.append(b);

        return this;

    }

    @Override

    public StringBuilder append(char c) {

        super.append(c);

        return this;

    }

    @Override

    public StringBuilder append(int i) {

        super.append(i);

        return this;

    }

    @Override

    public StringBuilder append(long lng) {

        super.append(lng);

        return this;

    }

    @Override

    public StringBuilder append(float f) {

        super.append(f);

        return this;

    }

    @Override

    public StringBuilder append(double d) {

        super.append(d);

        return this;

    }

    /**

     * @since 1.5

     */

    @Override

    public StringBuilder appendCodePoint(int codePoint) {

        super.appendCodePoint(codePoint);

        return this;

    }

    /**

     * @throws StringIndexOutOfBoundsException {@inheritDoc}

     */

    @Override

    public StringBuilder delete(int start, int end) {

        super.delete(start, end);

        return this;

    }

    /**

     * @throws StringIndexOutOfBoundsException {@inheritDoc}

     */

    @Override

    public StringBuilder deleteCharAt(int index) {

        super.deleteCharAt(index);

        return this;

    }

    /**

     * @throws StringIndexOutOfBoundsException {@inheritDoc}

     */

    @Override

    public StringBuilder replace(int start, int end, String str) {

        super.replace(start, end, str);

        return this;

    }

    /**

     * @throws StringIndexOutOfBoundsException {@inheritDoc}

     */

    @Override

    public StringBuilder insert(int index, char[] str, int offset,

                                int len)

    {

        super.insert(index, str, offset, len);

        return this;

    }

    /**

     * @throws StringIndexOutOfBoundsException {@inheritDoc}

     */

    @Override

    public StringBuilder insert(int offset, Object obj) {

            super.insert(offset, obj);

            return this;

    }

    /**

     * @throws StringIndexOutOfBoundsException {@inheritDoc}

     */

    @Override

    public StringBuilder insert(int offset, String str) {

        super.insert(offset, str);

        return this;

    }

    /**

     * @throws StringIndexOutOfBoundsException {@inheritDoc}

     */

    @Override

    public StringBuilder insert(int offset, char[] str) {

        super.insert(offset, str);

        return this;

    }

    /**

     * @throws IndexOutOfBoundsException {@inheritDoc}

     */

    @Override

    public StringBuilder insert(int dstOffset, CharSequence s) {

            super.insert(dstOffset, s);

            return this;

    }

    /**

     * @throws IndexOutOfBoundsException {@inheritDoc}

     */

    @Override

    public StringBuilder insert(int dstOffset, CharSequence s,

                                int start, int end)

    {

        super.insert(dstOffset, s, start, end);

        return this;

    }

    /**

     * @throws StringIndexOutOfBoundsException {@inheritDoc}

     */

    @Override

    public StringBuilder insert(int offset, boolean b) {

        super.insert(offset, b);

        return this;

    }

    /**

     * @throws IndexOutOfBoundsException {@inheritDoc}

     */

    @Override

    public StringBuilder insert(int offset, char c) {

        super.insert(offset, c);

        return this;

    }

    /**

     * @throws StringIndexOutOfBoundsException {@inheritDoc}

     */

    @Override

    public StringBuilder insert(int offset, int i) {

        super.insert(offset, i);

        return this;

    }

    /**

     * @throws StringIndexOutOfBoundsException {@inheritDoc}

     */

    @Override

    public StringBuilder insert(int offset, long l) {

        super.insert(offset, l);

        return this;

    }

    /**

     * @throws StringIndexOutOfBoundsException {@inheritDoc}

     */

    @Override

    public StringBuilder insert(int offset, float f) {

        super.insert(offset, f);

        return this;

    }

    /**

     * @throws StringIndexOutOfBoundsException {@inheritDoc}

     */

    @Override

    public StringBuilder insert(int offset, double d) {

        super.insert(offset, d);

        return this;

    }

    /**

     * @throws NullPointerException {@inheritDoc}

     */

    @Override

    public int indexOf(String str) {

        return super.indexOf(str);

    }

    /**

     * @throws NullPointerException {@inheritDoc}

     */

    @Override

    public int indexOf(String str, int fromIndex) {

        return super.indexOf(str, fromIndex);

    }

    /**

     * @throws NullPointerException {@inheritDoc}

     */

    @Override

    public int lastIndexOf(String str) {

        return super.lastIndexOf(str);

    }

    /**

     * @throws NullPointerException {@inheritDoc}

     */

    @Override

    public int lastIndexOf(String str, int fromIndex) {

        return super.lastIndexOf(str, fromIndex);

    }

    @Override

    public StringBuilder reverse() {

        super.reverse();

        return this;

    }

    @Override

    public String toString() {

        // Create a copy, don't share the array

        return new String(value, 0, count);

    }

    /**

     * Save the state of the <tt>StringBuilder</tt> instance to a stream

     * (that is, serialize it).

     *

     * @serialData the number of characters currently stored in the string

     *             builder (<tt>int</tt>), followed by the characters in the

     *             string builder (<tt>char[]</tt>).   The length of the

     *             <tt>char</tt> array may be greater than the number of

     *             characters currently stored in the string builder, in which

     *             case extra characters are ignored.

     */

    private void writeObject(java.io.ObjectOutputStream s)

        throws java.io.IOException {

        s.defaultWriteObject();

        s.writeInt(count);

        s.writeObject(value);

    }

    /**

     * 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 {

        s.defaultReadObject();

        count = s.readInt();

        value = (char[]) s.readObject();

    }

}