### Iterators

The new [iter] package provides the basic definitions for working with
user-defined iterators.

The [slices] package adds several functions that work with iterators:
- [All](/pkg/slices#All) returns an iterator over slice indexes and values.
- [Values](/pkg/slices#Values) returns an iterator over slice elements.
- [Backward](/pkg/slices#Backward) returns an iterator that loops over
  a slice backward.

            }
        } else {
            Iterator<? extends Spec<? super T>> iterator = specs.iterator();
            if (!iterator.hasNext()) {
                this.specs = uncheckedCast(EMPTY);
            } else {
                this.specs = uncheckedCast(Iterators.toArray(iterator, Spec.class));
            }
        }
    }

    }

    @Override
    public boolean contains(File file) {
        return collection.contains(file) && filterSpec.isSatisfiedBy(file);
    }

    @Override
    public Iterator<File> iterator() {
        return Iterators.filter(collection.iterator(), filterSpec::isSatisfiedBy);
    }

    @Override
    public Optional<FileCollectionExecutionTimeValue> calculateExecutionTimeValue() {

        pathTo(edge, new ArrayList<>(), acc, new HashSet<>());
        List<String> result = Lists.newArrayListWithCapacity(acc.size());
        for (List<EdgeState> path : acc) {
            EdgeState target = Iterators.getLast(path.iterator());
            StringBuilder sb = new StringBuilder();
            if (target.getSelector().getDependencyMetadata().isConstraint()) {
                sb.append("Constraint path ");
            } else {

  public int hashCode() {
    return Sets.hashCodeImpl(this);
  }

  // This declaration is needed to make Set.iterator() and
  // ImmutableCollection.iterator() appear consistent to javac's type inference.
  @Override
  public abstract UnmodifiableIterator<E> iterator();

  abstract static class CachingAsList<E> extends ImmutableSet<E> {
    @LazyInit private transient ImmutableList<E> asList;

    @Override

        configuration.attributes >> Stub(AttributeContainerInternal)
        configuration.excludeRules >> ([] as Set)
        dependencySet.iterator() >> [].iterator()
        dependencyConstraintSet.iterator() >> [].iterator()

        configurationsProvider.setTheOnlyConfiguration(configuration)
    }

    def "builds configuration with no dependencies or exclude rules"() {
        when:

        return new FilePropertyContainer<T>();
    }

    public void add(T property) {
        properties.add(property);
        changed = true;
    }

    @Override
    public Iterator<T> iterator() {
        if (changed) {
            for (T propertySpec : properties) {
                String propertyName = propertySpec.getPropertyName();
                if (propertyName == null) {

        @Nonnull
        public Optional<Lifecycle> lookup(String id) {
            return getDelegate().lookup(id);
        }

        @Override
        public Iterator<Lifecycle> iterator() {
            return getDelegate().iterator();
        }

        protected LifecycleRegistry getDelegate() {
            return lifecycleRegistry;
        }
    }

        @Nonnull
        public Optional<Lifecycle> lookup(String id) {
            return getDelegate().lookup(id);
        }

        @Override
        public Iterator<Lifecycle> iterator() {
            return getDelegate().iterator();
        }

        protected LifecycleRegistry getDelegate() {
            return lifecycleRegistry;
        }
    }

    private static String join(Set<String> strings, String delimiter) {
        StringBuilder result = new StringBuilder();
        Iterator<String> iterator = strings.iterator();

        while (iterator.hasNext()) {
            result.append(iterator.next());
            if (iterator.hasNext()) {
                result.append(delimiter);
            }
        }

        return result.toString();
    }