org.qas.api.internal.util.google.collect

Class Iterators

java.lang.Object

org.qas.api.internal.util.google.collect.Iterators

public final class Iterators
extends java.lang.Object

This class contains static utility methods that operate on or return objects of type Iterator. Except as noted, each method has a corresponding Iterable-based method in the Iterables class.

Performance notes: Unless otherwise noted, all of the iterators produced in this class are lazy, which means that they only advance the backing iteration when absolutely necessary.

See the Guava User Guide section on Iterators.

Since:

1.0

Method Summary

Modifier and Type	Method and Description
static <T> boolean	addAll(java.util.Collection<T> addTo, java.util.Iterator<? extends T> iterator) Adds all elements in iterator to collection.
static boolean	elementsEqual(java.util.Iterator<?> iterator1, java.util.Iterator<?> iterator2) Determines whether two iterators contain equal elements in the same order.
static <T> UnmodifiableIterator<T>	emptyIterator() Returns the empty iterator.
static <T> UnmodifiableIterator<T>	forArray(T... array) Returns an iterator containing the elements of array in order.
static <T> UnmodifiableIterator<T>	singletonIterator(T value) Returns an iterator containing only value.
static int	size(java.util.Iterator<?> iterator) Returns the number of elements remaining in iterator.
static <T> UnmodifiableIterator<T>	unmodifiableIterator(java.util.Iterator<T> iterator) Returns an unmodifiable view of iterator.

Methods inherited from class java.lang.Object

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

Method Detail

emptyIterator

public static <T> UnmodifiableIterator<T> emptyIterator()

Returns the empty iterator.

unmodifiableIterator

public static <T> UnmodifiableIterator<T> unmodifiableIterator(java.util.Iterator<T> iterator)

Returns an unmodifiable view of iterator.

size

public static int size(java.util.Iterator<?> iterator)

Returns the number of elements remaining in iterator. The iterator will be left exhausted: its hasNext() method will return false.

elementsEqual

public static boolean elementsEqual(java.util.Iterator<?> iterator1,
                                    java.util.Iterator<?> iterator2)

Determines whether two iterators contain equal elements in the same order. More specifically, this method returns true if iterator1 and iterator2 contain the same number of elements and every element of iterator1 is equal to the corresponding element of iterator2.

Note that this will modify the supplied iterators, since they will have been advanced some number of elements forward.

forArray

public static <T> UnmodifiableIterator<T> forArray(T... array)

Returns an iterator containing the elements of array in order. The returned iterator is a view of the array; subsequent changes to the array will be reflected in the iterator.

Note: It is often preferable to represent your data using a collection type, for example using Arrays.asList(Object[]), making this method unnecessary.

The Iterable equivalent of this method is either Arrays.asList(Object[]), ImmutableList.copyOf(Object[])}, or ImmutableList.of().

singletonIterator

public static <T> UnmodifiableIterator<T> singletonIterator(T value)

Returns an iterator containing only value.

The Iterable equivalent of this method is Collections.singleton(T).

addAll

public static <T> boolean addAll(java.util.Collection<T> addTo,
                                 java.util.Iterator<? extends T> iterator)

Adds all elements in iterator to collection. The iterator will be left exhausted: its hasNext() method will return false.

Returns:

true if collection was modified as a result of this operation