Class MinimalIterable<E extends @Nullable Object>

java.lang.Object
com.google.common.collect.testing.MinimalIterable<E>
All Implemented Interfaces:
Iterable<E>
@GwtCompatible public final class MinimalIterable<E extends @Nullable Object> extends Object implements Iterable<E>
An implementation of Iterable which throws an exception on all invocations of the iterator() method after the first, and whose iterator is always unmodifiable.

The Iterable specification does not make it absolutely clear what should happen on a second invocation, so implementors have made various choices, including:

  • returning the same iterator again
  • throwing an exception of some kind
  • or the usual, robust behavior, which all known Collection implementations have, of returning a new, independent iterator

Because of this situation, any public method accepting an iterable should invoke the iterator method only once, and should be tested using this class. Exceptions to this rule should be clearly documented.

Note that although your APIs should be liberal in what they accept, your methods which return iterables should make every attempt to return ones of the robust variety.

This testing utility is not thread-safe.

Author:
Kevin Bourrillion

  • Method Details

    • of

      public static <E extends @Nullable Object> MinimalIterable<E> of(E... elements)
      Returns an iterable whose iterator returns the given elements in order.

    • from

      public static <E extends @Nullable Object> MinimalIterable<E> from(Collection<E> elements)
      Returns an iterable whose iterator returns the given elements in order. The elements are copied out of the source collection at the time this method is called.

    • iterator

      public Iterator<E> iterator()
      Specified by:
      iterator in interface Iterable<E extends @Nullable Object>