java.lang.Object | |
↳ | java.lang.StringBuilder |
A modifiable sequence of characters
for use in creating
strings. This class is intended as a direct replacement of
StringBuffer
for non-concurrent use; unlike StringBuffer
this
class is not synchronized.
For particularly complex string-building needs, consider Formatter
.
The majority of the modification methods on this class return this
so that method calls can be chained together. For example:
new StringBuilder("a").append("b").append("c").toString()
.
Public Constructors | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|
Constructs an instance with an initial capacity of
16 . | |||||||||||
Constructs an instance with the specified capacity.
| |||||||||||
Constructs an instance that's initialized with the contents of the
specified
CharSequence . | |||||||||||
Constructs an instance that's initialized with the contents of the
specified
String . |
Public Methods | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|
Appends the string representation of the specified subset of the
char[] . | |||||||||||
Appends the string representation of the specified
double value. | |||||||||||
Appends the string representation of the specified
char value. | |||||||||||
Appends the string representation of the specified
boolean value. | |||||||||||
Appends the string representation of the specified
long value. | |||||||||||
Appends the string representation of the specified
float value. | |||||||||||
Appends the string representation of the specified
char[] . | |||||||||||
Appends the string representation of the specified
int value. | |||||||||||
Appends the contents of the specified string.
| |||||||||||
Appends the string representation of the specified subsequence of the
CharSequence . | |||||||||||
Appends the contents of the specified
StringBuffer . | |||||||||||
Appends the string representation of the specified
Object . | |||||||||||
Appends the string representation of the specified
CharSequence . | |||||||||||
Appends the encoded Unicode code point.
| |||||||||||
Returns the number of characters that can be held without growing.
| |||||||||||
Returns the character at
index . | |||||||||||
Retrieves the Unicode code point value at the
index . | |||||||||||
Retrieves the Unicode code point value that precedes the
index . | |||||||||||
Calculates the number of Unicode code points between
start
and end . | |||||||||||
Deletes a sequence of characters specified by
start and end . | |||||||||||
Deletes the character at the specified index.
| |||||||||||
Ensures that this object has a minimum capacity available before
requiring the internal buffer to be enlarged.
| |||||||||||
Copies the requested sequence of characters into
dst passed
starting at dst . | |||||||||||
Searches for the index of the specified character.
| |||||||||||
Searches for the first index of the specified character.
| |||||||||||
Inserts the string representation of the specified subsequence of the
CharSequence at the specified offset . | |||||||||||
Inserts the string representation of the specified
Object at the
specified offset . | |||||||||||
Inserts the string representation of the specified
float value at
the specified offset . | |||||||||||
Inserts the string representation of the specified
char value at
the specified offset . | |||||||||||
Inserts the string representation of the specified
int value at
the specified offset . | |||||||||||
Inserts the string representation of the specified
char[] at the
specified offset . | |||||||||||
Inserts the string representation of the specified
double value
at the specified offset . | |||||||||||
Inserts the string representation of the specified
CharSequence
at the specified offset . | |||||||||||
Inserts the string representation of the specified subsequence of the
char[] at the specified offset . | |||||||||||
Inserts the specified string at the specified
offset . | |||||||||||
Inserts the string representation of the specified
long value at
the specified offset . | |||||||||||
Inserts the string representation of the specified
boolean value
at the specified offset . | |||||||||||
Searches for the index of the specified character.
| |||||||||||
Searches for the last index of the specified character.
| |||||||||||
The current length.
| |||||||||||
Returns the index that is offset
codePointOffset code points from
index . | |||||||||||
Replaces the specified subsequence in this builder with the specified
string.
| |||||||||||
Reverses the order of characters in this builder.
| |||||||||||
Sets the character at the
index . | |||||||||||
Sets the current length to a new value.
| |||||||||||
Returns a
CharSequence of the subsequence from the start
index to the end index. | |||||||||||
Returns the String value of the subsequence from the
start index
to the current end. | |||||||||||
Returns the String value of the subsequence from the
start index
to the end index. | |||||||||||
Returns the contents of this builder.
| |||||||||||
Trims off any extra capacity beyond the current length.
|
[Expand]
Inherited Methods | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|
From class
java.lang.Object
| |||||||||||
From interface
java.lang.Appendable
| |||||||||||
From interface
java.lang.CharSequence
|
Constructs an instance with an initial capacity of 16
.
Constructs an instance with the specified capacity.
capacity | the initial capacity to use. |
---|
NegativeArraySizeException | if the specified capacity is negative. |
---|
Constructs an instance that's initialized with the contents of the
specified CharSequence
. The capacity of the new builder will be
the length of the CharSequence
plus 16.
seq | the CharSequence to copy into the builder. |
---|
NullPointerException | if seq is null .
|
---|
Constructs an instance that's initialized with the contents of the
specified String
. The capacity of the new builder will be the
length of the String
plus 16.
str | the String to copy into the builder. |
---|
NullPointerException | if str is null .
|
---|
Appends the string representation of the specified subset of the char[]
. The char[]
value is converted to a String according to
the rule defined by valueOf(char[], int, int)
.
str | the char[] to append. |
---|---|
offset | the inclusive offset index. |
len | the number of characters. |
ArrayIndexOutOfBoundsException | if offset and len do not specify a valid
subsequence. |
---|
Appends the string representation of the specified double
value.
The double
value is converted to a string according to the rule
defined by valueOf(double)
.
d | the double value to append. |
---|
Appends the string representation of the specified char
value.
The char
value is converted to a string according to the rule
defined by valueOf(char)
.
c | the char value to append. |
---|
Appends the string representation of the specified boolean
value.
The boolean
value is converted to a String according to the rule
defined by valueOf(boolean)
.
b | the boolean value to append. |
---|
Appends the string representation of the specified long
value.
The long
value is converted to a string according to the rule
defined by valueOf(long)
.
l | the long value. |
---|
Appends the string representation of the specified float
value.
The float
value is converted to a string according to the rule
defined by valueOf(float)
.
f | the float value to append. |
---|
Appends the string representation of the specified char[]
.
The char[]
is converted to a string according to the rule
defined by valueOf(char[])
.
chars | the char[] to append.. |
---|
Appends the string representation of the specified int
value. The
int
value is converted to a string according to the rule defined
by valueOf(int)
.
i | the int value to append. |
---|
Appends the contents of the specified string. If the string is null
, then the string "null"
is appended.
str | the string to append. |
---|
Appends the string representation of the specified subsequence of the
CharSequence
. If the CharSequence
is null
, then
the string "null"
is used to extract the subsequence from.
csq | the CharSequence to append. |
---|---|
start | the beginning index. |
end | the ending index. |
IndexOutOfBoundsException | if start or end are negative, start
is greater than end or end is greater than
the length of csq .
|
---|
Appends the contents of the specified StringBuffer
. If the
StringBuffer is null
, then the string "null"
is
appended.
sb | the StringBuffer to append. |
---|
Appends the string representation of the specified Object
.
The Object
value is converted to a string according to the rule
defined by valueOf(Object)
.
obj | the Object to append. |
---|
Appends the string representation of the specified CharSequence
.
If the CharSequence
is null
, then the string "null"
is appended.
csq | the CharSequence to append. |
---|
Appends the encoded Unicode code point. The code point is converted to a
char[]
as defined by toChars(int)
.
codePoint | the Unicode code point to encode and append. |
---|
Returns the number of characters that can be held without growing.
Returns the character at index
.
IndexOutOfBoundsException | if index < 0 or index >= length() .
|
---|
Retrieves the Unicode code point value at the index
.
index | the index to the char code unit. |
---|
IndexOutOfBoundsException | if index is negative or greater than or equal to
length() . |
---|
Retrieves the Unicode code point value that precedes the index
.
index | the index to the char code unit within this object. |
---|
IndexOutOfBoundsException | if index is less than 1 or greater than
length() . |
---|
Calculates the number of Unicode code points between start
and end
.
start | the inclusive beginning index of the subsequence. |
---|---|
end | the exclusive end index of the subsequence. |
IndexOutOfBoundsException | if start is negative or greater than
end or end is greater than
length() . |
---|
Deletes a sequence of characters specified by start
and end
. Shifts any remaining characters to the left.
start | the inclusive start index. |
---|---|
end | the exclusive end index. |
StringIndexOutOfBoundsException | if start is less than zero, greater than the current
length or greater than end .
|
---|
Deletes the character at the specified index. shifts any remaining characters to the left.
index | the index of the character to delete. |
---|
StringIndexOutOfBoundsException | if index is less than zero or is greater than or
equal to the current length.
|
---|
Ensures that this object has a minimum capacity available before
requiring the internal buffer to be enlarged. The general policy of this
method is that if the minimumCapacity
is larger than the current
capacity()
, then the capacity will be increased to the largest
value of either the minimumCapacity
or the current capacity
multiplied by two plus two. Although this is the general policy, there is
no guarantee that the capacity will change.
min | the new minimum capacity to set. |
---|
Copies the requested sequence of characters into dst
passed
starting at dst
.
start | the inclusive start index of the characters to copy. |
---|---|
end | the exclusive end index of the characters to copy. |
dst | the char[] to copy the characters to. |
dstStart | the inclusive start index of dst to begin copying to. |
IndexOutOfBoundsException | if the start is negative, the dstStart is
negative, the start is greater than end , the
end is greater than the current length() or
dstStart + end - begin is greater than
dst.length .
|
---|
Searches for the index of the specified character. The search for the character starts at the specified offset and moves towards the end.
subString | the string to find. |
---|---|
start | the starting offset. |
Searches for the first index of the specified character. The search for the character starts at the beginning and moves towards the end.
string | the string to find. |
---|
Inserts the string representation of the specified subsequence of the
CharSequence
at the specified offset
. The CharSequence
is converted to a String as defined by
subSequence(int, int)
. If the CharSequence
is null
, then the string "null"
is used to determine the
subsequence.
offset | the index to insert at. |
---|---|
s | the CharSequence to insert. |
start | the start of the subsequence of the character sequence. |
end | the end of the subsequence of the character sequence. |
IndexOutOfBoundsException | if offset is negative or greater than the current
length() , or start and end do not
specify a valid subsequence. |
---|
Inserts the string representation of the specified Object
at the
specified offset
. The Object
value is converted to a
String according to the rule defined by valueOf(Object)
.
offset | the index to insert at. |
---|---|
obj | the Object to insert. |
StringIndexOutOfBoundsException | if offset is negative or greater than the current
length() . |
---|
Inserts the string representation of the specified float
value at
the specified offset
. The float
value is converted to a
string according to the rule defined by valueOf(float)
.
offset | the index to insert at. |
---|---|
f | the float value to insert. |
StringIndexOutOfBoundsException | if offset is negative or greater than the current
length() . |
---|
Inserts the string representation of the specified char
value at
the specified offset
. The char
value is converted to a
string according to the rule defined by valueOf(char)
.
offset | the index to insert at. |
---|---|
c | the char value to insert. |
IndexOutOfBoundsException | if offset is negative or greater than the current
length() . |
---|
Inserts the string representation of the specified int
value at
the specified offset
. The int
value is converted to a
String according to the rule defined by valueOf(int)
.
offset | the index to insert at. |
---|---|
i | the int value to insert. |
StringIndexOutOfBoundsException | if offset is negative or greater than the current
length() . |
---|
Inserts the string representation of the specified char[]
at the
specified offset
. The char[]
value is converted to a
String according to the rule defined by valueOf(char[])
.
offset | the index to insert at. |
---|---|
ch | the char[] to insert. |
StringIndexOutOfBoundsException | if offset is negative or greater than the current
length() . |
---|
Inserts the string representation of the specified double
value
at the specified offset
. The double
value is converted
to a String according to the rule defined by
valueOf(double)
.
offset | the index to insert at. |
---|---|
d | the double value to insert. |
StringIndexOutOfBoundsException | if offset is negative or greater than the current
length() . |
---|
Inserts the string representation of the specified CharSequence
at the specified offset
. The CharSequence
is converted
to a String as defined by toString()
. If s
is null
, then the String "null"
is inserted.
offset | the index to insert at. |
---|---|
s | the CharSequence to insert. |
IndexOutOfBoundsException | if offset is negative or greater than the current
length() . |
---|
Inserts the string representation of the specified subsequence of the
char[]
at the specified offset
. The char[]
value
is converted to a String according to the rule defined by
valueOf(char[], int, int)
.
offset | the index to insert at. |
---|---|
str | the char[] to insert. |
strOffset | the inclusive index. |
strLen | the number of characters. |
StringIndexOutOfBoundsException | if offset is negative or greater than the current
length() , or strOffset and strLen do
not specify a valid subsequence. |
---|
Inserts the specified string at the specified offset
. If the
specified string is null, then the String "null"
is inserted.
offset | the index to insert at. |
---|---|
str | the String to insert. |
StringIndexOutOfBoundsException | if offset is negative or greater than the current
length() .
|
---|
Inserts the string representation of the specified long
value at
the specified offset
. The long
value is converted to a
String according to the rule defined by valueOf(long)
.
offset | the index to insert at. |
---|---|
l | the long value to insert. |
StringIndexOutOfBoundsException | if offset is negative or greater than the current
{code length()}. |
---|
Inserts the string representation of the specified boolean
value
at the specified offset
. The boolean
value is converted
to a string according to the rule defined by
valueOf(boolean)
.
offset | the index to insert at. |
---|---|
b | the boolean value to insert. |
StringIndexOutOfBoundsException | if offset is negative or greater than the current
length . |
---|
Searches for the index of the specified character. The search for the character starts at the specified offset and moves towards the beginning.
subString | the string to find. |
---|---|
start | the starting offset. |
NullPointerException | if subString is null . |
---|
Searches for the last index of the specified character. The search for the character starts at the end and moves towards the beginning.
string | the string to find. |
---|
NullPointerException | if string is null . |
---|
The current length.
Returns the index that is offset codePointOffset
code points from
index
.
index | the index to calculate the offset from. |
---|---|
codePointOffset | the number of code points to count. |
codePointOffset
code points away from
index.IndexOutOfBoundsException | if index is negative or greater than
length() or if there aren't enough code points
before or after index to match
codePointOffset . |
---|
Replaces the specified subsequence in this builder with the specified string.
start | the inclusive begin index. |
---|---|
end | the exclusive end index. |
string | the replacement string. |
StringIndexOutOfBoundsException | if start is negative, greater than the current
length() or greater than end . |
---|---|
NullPointerException | if str is null .
|
Reverses the order of characters in this builder.
Sets the character at the index
.
index | the zero-based index of the character to replace. |
---|---|
ch | the character to set. |
IndexOutOfBoundsException | if index is negative or greater than or equal to the
current length() .
|
---|
Sets the current length to a new value. If the new length is larger than
the current length, then the new characters at the end of this object
will contain the Trims off any extra capacity beyond the current length. Note, this method
is NOT guaranteed to change the capacity of this object.char
value of
public
void
trimToSize
()