StringBuffer, but with no guarantee of synchronization.
+ * This class is designed for use as a drop-in replacement for
+ * StringBuffer 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
+ * StringBuffer as it will be faster under most implementations.
+ *
+ * The principal operations on a StringBuilder are the
+ * append and insert 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
+ * append method always adds these characters at the end
+ * of the builder; the insert method adds the characters at
+ * a specified point.
+ *
+ * For example, if z refers to a string builder object
+ * whose current contents are "start", then
+ * the method call z.append("le") would cause the string
+ * builder to contain "startle", whereas
+ * z.insert(4, "le") would alter the string builder to
+ * contain "starlet".
+ *
+ * In general, if sb refers to an instance of a StringBuilder,
+ * then sb.append(x) has the same effect as
+ * sb.insert(sb.length(), x).
+ *
+ * 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.
+ *
+ *
Instances of StringBuilder 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 capacity argument.
+ *
+ * @param capacity the initial capacity.
+ * @throws NegativeArraySizeException if the capacity
+ * argument is less than 0.
+ */
+ 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
+ * 16 plus the length of the string argument.
+ *
+ * @param str the initial contents of the buffer.
+ * @throws NullPointerException if str is null
+ */
+ public StringBuilder(String str) {
+ super(str.length() + 16);
+ append(str);
+ }
+
+ /**
+ * Constructs a string builder that contains the same characters
+ * as the specified CharSequence. The initial capacity of
+ * the string builder is 16 plus the length of the
+ * CharSequence argument.
+ *
+ * @param seq the sequence to copy.
+ * @throws NullPointerException if seq is null
+ */
+ public StringBuilder(CharSequence seq) {
+ this(seq.length() + 16);
+ append(seq);
+ }
+
+ public StringBuilder append(Object obj) {
+ return append(String.valueOf(obj));
+ }
+
+ public StringBuilder append(String str) {
+ super.append(str);
+ return this;
+ }
+
+ // Appends the specified string builder to this sequence.
+ private StringBuilder append(StringBuilder sb) {
+ if (sb == null)
+ return append("null");
+ int len = sb.length();
+ int newcount = count + len;
+ if (newcount > value.length)
+ expandCapacity(newcount);
+ sb.getChars(0, len, value, count);
+ count = newcount;
+ return this;
+ }
+
+ /**
+ * Appends the specified StringBuffer to this sequence.
+ *
+ * The characters of the StringBuffer argument are appended, + * in order, to this sequence, increasing the + * length of this sequence by the length of the argument. + * If sb is null, then the four characters + * "null" are appended to this sequence. + *
+ * Let n be the length of this character sequence just prior to
+ * execution of the append method. Then the character at index
+ * k in the new character sequence is equal to the character at
+ * index k in the old character sequence, if k is less than
+ * n; otherwise, it is equal to the character at index k-n
+ * in the argument sb.
+ *
+ * @param sb the StringBuffer to append.
+ * @return a reference to this object.
+ */
+ public StringBuilder append(StringBuffer sb) {
+ super.append(sb);
+ return this;
+ }
+
+ /**
+ */
+ public StringBuilder append(CharSequence s) {
+ if (s == null)
+ s = "null";
+ if (s instanceof String)
+ return this.append((String)s);
+ if (s instanceof StringBuffer)
+ return this.append((StringBuffer)s);
+ if (s instanceof StringBuilder)
+ return this.append((StringBuilder)s);
+ return this.append(s, 0, s.length());
+ }
+
+ /**
+ * @throws IndexOutOfBoundsException {@inheritDoc}
+ */
+ public StringBuilder append(CharSequence s, int start, int end) {
+ super.append(s, start, end);
+ return this;
+ }
+
+ public StringBuilder append(char[] str) {
+ super.append(str);
+ return this;
+ }
+
+ /**
+ * @throws IndexOutOfBoundsException {@inheritDoc}
+ */
+ public StringBuilder append(char[] str, int offset, int len) {
+ super.append(str, offset, len);
+ return this;
+ }
+
+ public StringBuilder append(boolean b) {
+ super.append(b);
+ return this;
+ }
+
+ public StringBuilder append(char c) {
+ super.append(c);
+ return this;
+ }
+
+ public StringBuilder append(int i) {
+ super.append(i);
+ return this;
+ }
+
+ public StringBuilder append(long lng) {
+ super.append(lng);
+ return this;
+ }
+
+ public StringBuilder append(float f) {
+ super.append(f);
+ return this;
+ }
+
+ public StringBuilder append(double d) {
+ super.append(d);
+ return this;
+ }
+
+ /**
+ * @since 1.5
+ */
+ public StringBuilder appendCodePoint(int codePoint) {
+ super.appendCodePoint(codePoint);
+ return this;
+ }
+
+ /**
+ * @throws StringIndexOutOfBoundsException {@inheritDoc}
+ */
+ public StringBuilder delete(int start, int end) {
+ super.delete(start, end);
+ return this;
+ }
+
+ /**
+ * @throws StringIndexOutOfBoundsException {@inheritDoc}
+ */
+ public StringBuilder deleteCharAt(int index) {
+ super.deleteCharAt(index);
+ return this;
+ }
+
+ /**
+ * @throws StringIndexOutOfBoundsException {@inheritDoc}
+ */
+ public StringBuilder replace(int start, int end, String str) {
+ super.replace(start, end, str);
+ return this;
+ }
+
+ /**
+ * @throws StringIndexOutOfBoundsException {@inheritDoc}
+ */
+ public StringBuilder insert(int index, char[] str, int offset,
+ int len)
+ {
+ super.insert(index, str, offset, len);
+ return this;
+ }
+
+ /**
+ * @throws StringIndexOutOfBoundsException {@inheritDoc}
+ */
+ public StringBuilder insert(int offset, Object obj) {
+ return insert(offset, String.valueOf(obj));
+ }
+
+ /**
+ * @throws StringIndexOutOfBoundsException {@inheritDoc}
+ */
+ public StringBuilder insert(int offset, String str) {
+ super.insert(offset, str);
+ return this;
+ }
+
+ /**
+ * @throws StringIndexOutOfBoundsException {@inheritDoc}
+ */
+ public StringBuilder insert(int offset, char[] str) {
+ super.insert(offset, str);
+ return this;
+ }
+
+ /**
+ * @throws IndexOutOfBoundsException {@inheritDoc}
+ */
+ public StringBuilder insert(int dstOffset, CharSequence s) {
+ 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}
+ */
+ public StringBuilder insert(int dstOffset, CharSequence s,
+ int start, int end)
+ {
+ super.insert(dstOffset, s, start, end);
+ return this;
+ }
+
+ /**
+ * @throws StringIndexOutOfBoundsException {@inheritDoc}
+ */
+ public StringBuilder insert(int offset, boolean b) {
+ super.insert(offset, b);
+ return this;
+ }
+
+ /**
+ * @throws IndexOutOfBoundsException {@inheritDoc}
+ */
+ public StringBuilder insert(int offset, char c) {
+ super.insert(offset, c);
+ return this;
+ }
+
+ /**
+ * @throws StringIndexOutOfBoundsException {@inheritDoc}
+ */
+ public StringBuilder insert(int offset, int i) {
+ return insert(offset, String.valueOf(i));
+ }
+
+ /**
+ * @throws StringIndexOutOfBoundsException {@inheritDoc}
+ */
+ public StringBuilder insert(int offset, long l) {
+ return insert(offset, String.valueOf(l));
+ }
+
+ /**
+ * @throws StringIndexOutOfBoundsException {@inheritDoc}
+ */
+ public StringBuilder insert(int offset, float f) {
+ return insert(offset, String.valueOf(f));
+ }
+
+ /**
+ * @throws StringIndexOutOfBoundsException {@inheritDoc}
+ */
+ public StringBuilder insert(int offset, double d) {
+ return insert(offset, String.valueOf(d));
+ }
+
+ /**
+ * @throws NullPointerException {@inheritDoc}
+ */
+ public int indexOf(String str) {
+ return indexOf(str, 0);
+ }
+
+ /**
+ * @throws NullPointerException {@inheritDoc}
+ */
+ public int indexOf(String str, int fromIndex) {
+ return super.indexOf(str, fromIndex);
+ }
+
+ /**
+ * @throws NullPointerException {@inheritDoc}
+ */
+ public int lastIndexOf(String str) {
+ return lastIndexOf(str, count);
+ }
+
+ /**
+ * @throws NullPointerException {@inheritDoc}
+ */
+ public int lastIndexOf(String str, int fromIndex) {
+ return String.lastIndexOf(value, 0, count,
+ str.toCharArray(), 0, str.length(), fromIndex);
+ }
+
+ public StringBuilder reverse() {
+ super.reverse();
+ return this;
+ }
+
+ public String toString() {
+ // Create a copy, don't share the array
+ return new String(value, 0, count);
+ }
+
+ /**
+ * Save the state of the StringBuilder instance to a stream
+ * (that is, serialize it).
+ *
+ * @serialData the number of characters currently stored in the string
+ * builder (int), followed by the characters in the
+ * string builder (char[]). The length of the
+ * char 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();
+// }
+
+}