public
final
class
StringJoiner
extends Object
| java.lang.Object | |
| ↳ | java.util.StringJoiner |
StringJoiner is used to construct a sequence of characters separated
by a delimiter and optionally starting with a supplied prefix
and ending with a supplied suffix.
Prior to adding something to the StringJoiner, its
sj.toString() method will, by default, return prefix + suffix.
However, if the setEmptyValue method is called, the emptyValue
supplied will be returned instead. This can be used, for example, when
creating a string using set notation to indicate an empty set, i.e.
"{}", where the prefix is "{", the
suffix is "}" and nothing has been added to the
StringJoiner.
Public constructors | |
|---|---|
StringJoiner(CharSequence delimiter)
Constructs a |
|
StringJoiner(CharSequence delimiter, CharSequence prefix, CharSequence suffix)
Constructs a |
|
Public methods | |
|---|---|
StringJoiner
|
add(CharSequence newElement)
Adds a copy of the given |
int
|
length()
Returns the length of the |
StringJoiner
|
merge(StringJoiner other)
Adds the contents of the given |
StringJoiner
|
setEmptyValue(CharSequence emptyValue)
Sets the sequence of characters to be used when determining the string
representation of this |
String
|
toString()
Returns the current value, consisting of the |
Inherited methods | |
|---|---|
 From
class
java.lang.Object
| |
StringJoiner (CharSequence delimiter)
Constructs a StringJoiner with no characters in it, with no
prefix or suffix, and a copy of the supplied
delimiter.
If no characters are added to the StringJoiner and methods
accessing the value of it are invoked, it will not return a
prefix or suffix (or properties thereof) in the result,
unless setEmptyValue has first been called.
| Parameters | |
|---|---|
delimiter |
CharSequence:
the sequence of characters to be used between each
element added to the StringJoiner value |
| Throws | |
|---|---|
NullPointerException |
if delimiter is null
|
StringJoiner (CharSequence delimiter, CharSequence prefix, CharSequence suffix)
Constructs a StringJoiner with no characters in it using copies
of the supplied prefix, delimiter and suffix.
If no characters are added to the StringJoiner and methods
accessing the string value of it are invoked, it will return the
prefix + suffix (or properties thereof) in the result, unless
setEmptyValue has first been called.
| Parameters | |
|---|---|
delimiter |
CharSequence:
the sequence of characters to be used between each
element added to the StringJoiner |
prefix |
CharSequence:
the sequence of characters to be used at the beginning |
suffix |
CharSequence:
the sequence of characters to be used at the end |
| Throws | |
|---|---|
NullPointerException |
if prefix, delimiter, or
suffix is null
|
StringJoiner add (CharSequence newElement)
Adds a copy of the given CharSequence value as the next
element of the StringJoiner value. If newElement is
null, then "null" is added.
| Parameters | |
|---|---|
newElement |
CharSequence:
The element to add |
| Returns | |
|---|---|
StringJoiner |
a reference to this StringJoiner
|
int length ()
Returns the length of the String representation
of this StringJoiner. Note that if
no add methods have been called, then the length of the String
representation (either prefix + suffix or emptyValue)
will be returned. The value should be equivalent to
toString().length().
| Returns | |
|---|---|
int |
the length of the current value of StringJoiner
|
StringJoiner merge (StringJoiner other)
Adds the contents of the given StringJoiner without prefix and
suffix as the next element if it is non-empty. If the given StringJoiner is empty, the call has no effect.
A StringJoiner is empty if add()
has never been called, and if merge() has never been called
with a non-empty StringJoiner argument.
If the other StringJoiner is using a different delimiter,
then elements from the other StringJoiner are concatenated with
that delimiter and the result is appended to this StringJoiner
as a single element.
| Parameters | |
|---|---|
other |
StringJoiner:
The StringJoiner whose contents should be merged
into this one |
| Returns | |
|---|---|
StringJoiner |
This StringJoiner
|
| Throws | |
|---|---|
NullPointerException |
if the other StringJoiner is null |
StringJoiner setEmptyValue (CharSequence emptyValue)
Sets the sequence of characters to be used when determining the string
representation of this StringJoiner and no elements have been
added yet, that is, when it is empty. A copy of the emptyValue
parameter is made for this purpose. Note that once an add method has been
called, the StringJoiner is no longer considered empty, even if
the element(s) added correspond to the empty String.
| Parameters | |
|---|---|
emptyValue |
CharSequence:
the characters to return as the value of an empty
StringJoiner |
| Returns | |
|---|---|
StringJoiner |
this StringJoiner itself so the calls may be chained |
| Throws | |
|---|---|
NullPointerException |
when the emptyValue parameter is
null
|
String toString ()
Returns the current value, consisting of the prefix, the values
added so far separated by the delimiter, and the suffix,
unless no elements have been added in which case, the
prefix + suffix or the emptyValue characters are returned
| Returns | |
|---|---|
String |
the string representation of this StringJoiner
|
Developers