ca.infoway.messagebuilder.util.iterator
Class EmptyIterable<T>

java.lang.Object
  ca.infoway.messagebuilder.util.iterator.EmptyIterable<T>

Type Parameters:

T - - the element type of the iterable.

public class EmptyIterable<T>
extends Object

A utility that performs nullness checking on an iterable. If an iterable is null, then an empty iterable is returned, preventing a NullPointerException.

A typical use of this class is as follows: import static ca.infoway.messagebuilder.util.iterator.EmptyIterable.nullSafeIterable; ... public void doMethod() { for (String text : nullSafeIterable(getTextCollection)) { ... } } ...

Author:

Intelliware Development

Constructor Summary

EmptyIterable()

Method Summary

static <T> Iterable<T>	nullSafeIterable(Iterable<T> i) Check the incoming iterable type to see if it's null.
static <T> Iterable<T>	nullSafeIterable(T[] i) Check the incoming array to see if it's null.
static <K,V> Iterable<K>	nullSafeKeySetIterable(Map<K,V> map) Check the incoming map to see if it's null.
static <K,V> Iterable<V>	nullSafeValuesIterable(Map<K,V> map) Check the incoming map to see if it's null.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

EmptyIterable

public EmptyIterable()

Method Detail

nullSafeIterable

public static <T> Iterable<T> nullSafeIterable(Iterable<T> i)

Check the incoming iterable type to see if it's null.

Type Parameters:

T - - the type of object to iterate over

Parameters:

i - - the iterable type that might be null

Returns:

- the iterable types iterator if it's not null; an empty iterator otherwise

nullSafeIterable

public static <T> Iterable<T> nullSafeIterable(T[] i)

Check the incoming array to see if it's null.

Type Parameters:

T - - the element type of the array

Parameters:

i - - the array that might be null

Returns:

- an array iterator or an empty iterator

nullSafeKeySetIterable

public static <K,V> Iterable<K> nullSafeKeySetIterable(Map<K,V> map)

Check the incoming map to see if it's null. If not, return the keySet iterator, otherwise return an empty iterator.

Type Parameters:

K - - the key type of the map

V - - the value type of the map

Parameters:

map - - the map that might be null

Returns:

- the keyset iterator

nullSafeValuesIterable

public static <K,V> Iterable<V> nullSafeValuesIterable(Map<K,V> map)

Check the incoming map to see if it's null. If not, return the values iterator, otherwise return an empty iterator.

Type Parameters:

K - - the key type of the map

V - - the value type of the map

Parameters:

map - - the map that might be null

Returns:

- the values iterator