Java Reference
In-Depth Information
This operation appends a substring of
aString
consisting of four characters starting at index position 3
to the
StringBuffer
object,
buf
. The capacity of
buf
is automatically increased by the length of the
appended substring, if necessary.
Appending Basic Types
You have a set of versions of the
append()
method that will enable you to
append()
any of the basic
types to a
StringBuffer
object. These will accept arguments of any of the following types:
boolean
,
char
,
byte
,
short
,
int
,
long
,
float
, or
double
. In each case, the value is converted to a string
equivalent of the value, which is appended to the object, so a
boolean
variable will be appended as
either "
true
" or "
false
", and for numeric types the string will be a decimal representation of the
value. For example:
StringBuffer buf = new StringBuffer("The number is ");
long number = 999;
buf.append(number);
will result in
buf
containing the string "
The number
is
999
".
There is nothing to prevent you from appending constants to a
StringBuffer
object. For example, if
you now execute the statement:
buf.append(12.34);
the object
buf
will contain "
The
number
is
99912.34
"
.
There is also a version of the
append()
method which accepts an array of type
char
as an argument.
The contents of the array are appended to the
StringBuffer
object as a string. A further variation on
this enables you to append a subset of the elements from an array of type
char
by using two additional
arguments: one to specify the index of the first element to be appended, and another to specify the total
number of elements to be appended. An example of how you might use this is as follows;
char[] text = { 'i', 's', ' ', 'e', 'x', 'a', 'c', 't', 'l', 'y'};
buf.append(text, 2, 8);