com.google.common.base
Class Joiner

java.lang.Object
  extended by com.google.common.base.Joiner

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.

Author:
Kevin Bourrillion

Nested Class Summary
static class Joiner.MapJoiner
          An object that joins map entries in the same manner as Joiner joins iterables and arrays.
 
Method Summary
<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, 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, 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(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

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


on

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 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,
                                    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

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

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

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

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

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


withKeyValueSeparator

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