public class Joiner extends Object
Iterable
, varargs or even a
Map
) with a separator. It either appends the results to an Appendable
or returns
them as a String
. Example: Joiner joiner = Joiner.on("; ").skipNulls();
. . .
return joiner.join("Harry", null, "Ron", "Hermione");
This returns the string "Harry; Ron; Hermione"
. Note that all input elements are
converted to strings using Object.toString()
before being appended.
If neither skipNulls()
nor useForNull(String)
is specified, the joining
methods will throw NullPointerException
if any given element is null.
Warning: joiner instances are always immutable; a configuration method such as useForNull
has no effect on the instance it is invoked on! You must store and use the new joiner
instance returned by the method. This makes joiners thread-safe, and safe to store as static final
constants.
// Bad! Do not do this!
Joiner joiner = Joiner.on(',');
joiner.skipNulls(); // does nothing!
return joiner.join("wrong", null, "wrong");
See the Guava User Guide article on Joiner
.
Modifier and Type | Class and Description |
---|---|
static class |
Joiner.MapJoiner
An object that joins map entries in the same manner as
Joiner joins iterables and
arrays. |
Modifier and Type | Method and Description |
---|---|
<A extends Appendable> |
appendTo(A appendable,
Iterable<?> parts)
Appends the string representation of each of
parts , using the previously configured
separator between each, to appendable . |
<A extends Appendable> |
appendTo(A appendable,
Iterator<?> parts)
Appends the string representation of each of
parts , using the previously configured
separator between each, to appendable . |
<A extends Appendable> |
appendTo(A appendable,
Object[] parts)
Appends the string representation of each of
parts , using the previously configured
separator between each, to appendable . |
<A extends Appendable> |
appendTo(A appendable,
Object first,
Object second,
Object... rest)
Appends to
appendable the string representation of each of the remaining arguments. |
StringBuilder |
appendTo(StringBuilder builder,
Iterable<?> parts)
Appends the string representation of each of
parts , using the previously configured
separator between each, to builder . |
StringBuilder |
appendTo(StringBuilder builder,
Iterator<?> parts)
Appends the string representation of each of
parts , using the previously configured
separator between each, to builder . |
StringBuilder |
appendTo(StringBuilder builder,
Object[] parts)
Appends the string representation of each of
parts , using the previously configured
separator between each, to builder . |
StringBuilder |
appendTo(StringBuilder builder,
Object first,
Object second,
Object... rest)
Appends to
builder the string representation of each of the remaining arguments. |
String |
join(Iterable<?> parts)
Returns a string containing the string representation of each of
parts , using the
previously configured separator between each. |
String |
join(Iterator<?> parts)
Returns a string containing the string representation of each of
parts , using the
previously configured separator between each. |
String |
join(Object[] parts)
Returns a string containing the string representation of each of
parts , using the
previously configured separator between each. |
String |
join(Object first,
Object second,
Object... rest)
Returns a string containing the string representation of each argument, using the previously
configured separator between each.
|
static Joiner |
on(char separator)
Returns a joiner which automatically places
separator between consecutive elements. |
static Joiner |
on(String separator)
Returns a joiner which automatically places
separator between consecutive elements. |
Joiner |
skipNulls()
Returns a joiner with the same behavior as this joiner, except automatically skipping over any
provided null elements.
|
Joiner |
useForNull(String nullText)
Returns a joiner with the same behavior as this one, except automatically substituting
nullText for any provided null elements. |
Joiner.MapJoiner |
withKeyValueSeparator(String keyValueSeparator)
Returns a
MapJoiner using the given key-value separator, and the same configuration as
this Joiner otherwise. |
public static Joiner on(String separator)
separator
between consecutive elements.public static Joiner on(char separator)
separator
between consecutive elements.public <A extends Appendable> A appendTo(A appendable, Iterable<?> parts) throws IOException
parts
, using the previously configured
separator between each, to appendable
.IOException
public <A extends Appendable> A appendTo(A appendable, Iterator<?> parts) throws IOException
parts
, using the previously configured
separator between each, to appendable
.IOException
public final <A extends Appendable> A appendTo(A appendable, Object[] parts) throws IOException
parts
, using the previously configured
separator between each, to appendable
.IOException
public final <A extends Appendable> A appendTo(A appendable, Object first, Object second, Object... rest) throws IOException
appendable
the string representation of each of the remaining arguments.IOException
public final StringBuilder appendTo(StringBuilder builder, Iterable<?> parts)
parts
, using the previously configured
separator between each, to builder
. Identical to appendTo(Appendable,
Iterable)
, except that it does not throw IOException
.public final StringBuilder appendTo(StringBuilder builder, Iterator<?> parts)
parts
, using the previously configured
separator between each, to builder
. Identical to appendTo(Appendable,
Iterable)
, except that it does not throw IOException
.public final StringBuilder appendTo(StringBuilder builder, Object[] parts)
parts
, using the previously configured
separator between each, to builder
. Identical to appendTo(Appendable,
Iterable)
, except that it does not throw IOException
.public final StringBuilder appendTo(StringBuilder builder, Object first, Object second, Object... rest)
builder
the string representation of each of the remaining arguments.
Identical to appendTo(Appendable, Object, Object, Object...)
, except that it does not
throw IOException
.public final String join(Iterable<?> parts)
parts
, using the
previously configured separator between each.public final String join(Iterator<?> parts)
parts
, using the
previously configured separator between each.public final String join(Object[] parts)
parts
, using the
previously configured separator between each.public final String join(Object first, Object second, Object... rest)
public Joiner useForNull(String nullText)
nullText
for any provided null elements.public Joiner skipNulls()
public Joiner.MapJoiner withKeyValueSeparator(String keyValueSeparator)
MapJoiner
using the given key-value separator, and the same configuration as
this Joiner
otherwise.Copyright © 2013-2015 impossibl.com. All Rights Reserved.