Joiner (Guava: Google Core Libraries for Java 19.0 API)

java.lang.Object
- com.google.common.base.Joiner

```
@GwtCompatible
public class Joiner
extends Object
```
An object which joins pieces of text (specified as an array, 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.
Since:

2.0

Author:

Kevin Bourrillion

Nested Class Summary

Nested Classes
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.

Nested Classes
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.

Method Summary

Methods
Modifier and Type	Method and Description
`<A extends Appendable> A`	`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> A`	`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> A`	`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> A`	`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.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Detail

on
```
@CheckReturnValue
public static Joiner on(String separator)
```
Returns a joiner which automatically places separator between consecutive elements.

on
```
@CheckReturnValue
public static Joiner on(char separator)
```
Returns a joiner which automatically places separator between consecutive elements.

appendTo

public <A extends Appendable> A appendTo(A appendable,
                                Iterable<?> parts)
                              throws IOException

Appends the string representation of each of parts, using the previously configured separator between each, to appendable.

Throws:: IOException

appendTo

public <A extends Appendable> A appendTo(A appendable,
                                Iterator<?> parts)
                              throws IOException

Appends the string representation of each of parts, using the previously configured separator between each, to appendable.

Throws:: IOException
Since:: 11.0

appendTo

public final <A extends Appendable> A appendTo(A appendable,
                                Object[] parts)
                                    throws IOException

Appends the string representation of each of parts, using the previously configured separator between each, to appendable.

Throws:: IOException

appendTo

public final <A extends Appendable> A appendTo(A appendable,
                                @Nullable
                                Object first,
                                @Nullable
                                Object second,
                                Object... rest)
                                    throws IOException

Appends to appendable the string representation of each of the remaining arguments.

Throws:: IOException

appendTo
```
public final StringBuilder appendTo(StringBuilder builder,
                     Iterable<?> parts)
```
Appends the string representation of each of parts, using the previously configured separator between each, to builder. Identical to appendTo(Appendable, Iterable), except that it does not throw IOException.

appendTo
```
public final StringBuilder appendTo(StringBuilder builder,
                     Iterator<?> parts)
```
Appends the string representation of each of parts, using the previously configured separator between each, to builder. Identical to appendTo(Appendable, Iterable), except that it does not throw IOException.

Since:

11.0

appendTo
```
public final StringBuilder appendTo(StringBuilder builder,
                     Object[] parts)
```
Appends the string representation of each of parts, using the previously configured separator between each, to builder. Identical to appendTo(Appendable, Iterable), except that it does not throw IOException.

appendTo

public final StringBuilder appendTo(StringBuilder builder,
                     @Nullable
                     Object first,
                     @Nullable
                     Object second,
                     Object... rest)

Appends to builder the string representation of each of the remaining arguments. Identical to appendTo(Appendable, Object, Object, Object...), except that it does not throw IOException.

join
```
@CheckReturnValue
public final String join(Iterable<?> parts)
```
Returns a string containing the string representation of each of parts, using the previously configured separator between each.

join
```
@CheckReturnValue
public final String join(Iterator<?> parts)
```
Returns a string containing the string representation of each of parts, using the previously configured separator between each.

Since:

11.0

join
```
@CheckReturnValue
public final String join(Object[] parts)
```
Returns a string containing the string representation of each of parts, using the previously configured separator between each.

join

@CheckReturnValue
public final String join(@Nullable
                           Object first,
                           @Nullable
                           Object second,
                           Object... rest)

Returns a string containing the string representation of each argument, using the previously configured separator between each.

useForNull
```
@CheckReturnValue
public Joiner useForNull(String nullText)
```
Returns a joiner with the same behavior as this one, except automatically substituting nullText for any provided null elements.

skipNulls
```
@CheckReturnValue
public Joiner skipNulls()
```
Returns a joiner with the same behavior as this joiner, except automatically skipping over any provided null elements.

withKeyValueSeparator
```
@CheckReturnValue
public Joiner.MapJoiner withKeyValueSeparator(String keyValueSeparator)
```
Returns a MapJoiner using the given key-value separator, and the same configuration as this Joiner otherwise.

Class Joiner

Nested Class Summary

Method Summary

Methods inherited from class java.lang.Object

Method Detail

on

on

appendTo

appendTo

appendTo

appendTo

appendTo

appendTo

appendTo

appendTo

join

join

join

join

useForNull

skipNulls

withKeyValueSeparator