Extends:
AbstractStringBuilder
A mutable sequence of characters. This class provides an API compatible
with
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 java.lang.StringBuffer be used.
| Methods |
|---|
| public StringBuilder |
append(Object obj)
|
| public StringBuilder |
append(String str)
|
| public StringBuilder |
append(StringBuffer sb)
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.
| sb | the StringBuffer to append. |
| return | a reference to this object. |
|
| public StringBuilder |
append(CharSequence s)
|
| public StringBuilder |
append(CharSequence s, int start, int end)
| Throws | IndexOutOfBoundsException: if
start or end are negative, or
start is greater than end or
end is greater than s.length() |
|
| public StringBuilder |
append(char[] str)
|
| public StringBuilder |
append(char[] str, int offset, int len)
|
| public StringBuilder |
append(boolean b)
|
| public StringBuilder |
append(char c)
|
| public StringBuilder |
append(int i)
|
| public StringBuilder |
append(long lng)
|
| public StringBuilder |
append(float f)
|
| public StringBuilder |
append(double d)
|
| public StringBuilder |
appendCodePoint(int codePoint)
|
| public StringBuilder |
delete(int start, int end)
|
| public StringBuilder |
deleteCharAt(int index)
|
| public int |
indexOf(String str)
|
| public int |
indexOf(String str, int fromIndex)
|
| public StringBuilder |
insert(int index, char[] str, int offset, int len)
| Throws | StringIndexOutOfBoundsException: if index
is negative or greater than length(), or
offset or len are negative, or
(offset+len) is greater than
str.length. |
|
| public StringBuilder |
insert(int offset, Object obj)
|
| public StringBuilder |
insert(int offset, String str)
|
| public StringBuilder |
insert(int offset, char[] str)
|
| public StringBuilder |
insert(int dstOffset, CharSequence s)
|
| public StringBuilder |
insert(int dstOffset, CharSequence s, int start, int end)
| Throws | IndexOutOfBoundsException: if dstOffset
is negative or greater than this.length(), or
start or end are negative, or
start is greater than end or
end is greater than s.length() |
|
| public StringBuilder |
insert(int offset, boolean b)
|
| public StringBuilder |
insert(int offset, char c)
|
| public StringBuilder |
insert(int offset, int i)
|
| public StringBuilder |
insert(int offset, long l)
|
| public StringBuilder |
insert(int offset, float f)
|
| public StringBuilder |
insert(int offset, double d)
|
| public int |
lastIndexOf(String str)
|
| public int |
lastIndexOf(String str, int fromIndex)
|
| public StringBuilder |
replace(int start, int end, String str)
|
| public StringBuilder |
reverse()
|
| public String |
toString()
|
