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);
}
@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 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;
}
@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 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();
}
}