diff options
Diffstat (limited to 'src/main/java/com/google/devtools/build/lib/collect/ImmutableIterable.java')
-rw-r--r-- | src/main/java/com/google/devtools/build/lib/collect/ImmutableIterable.java | 48 |
1 files changed, 48 insertions, 0 deletions
diff --git a/src/main/java/com/google/devtools/build/lib/collect/ImmutableIterable.java b/src/main/java/com/google/devtools/build/lib/collect/ImmutableIterable.java new file mode 100644 index 0000000000..74fab835cb --- /dev/null +++ b/src/main/java/com/google/devtools/build/lib/collect/ImmutableIterable.java @@ -0,0 +1,48 @@ +// Copyright 2014 Google Inc. All rights reserved. +// +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + +package com.google.devtools.build.lib.collect; + +import java.util.Iterator; + +/** + * A wrapper that signals the immutability of a certain iterable. + * + * <p>Intended for use in scenarios when you have an iterable that is de facto immutable, + * but is not recognized as such by {@link CollectionUtils#checkImmutable(Iterable)}. + * + * <p>Only use this when you know that the contents of the underlying iterable will never change, + * or you will be setting yourself up for aliasing bugs. + */ +public final class ImmutableIterable<T> implements Iterable<T> { + + private final Iterable<T> iterable; + + private ImmutableIterable(Iterable<T> iterable) { + this.iterable = iterable; + } + + @Override + public Iterator<T> iterator() { + return iterable.iterator(); + } + + /** + * Creates an {@link ImmutableIterable} instance. + */ + // Use a factory method in order to avoid having to specify generic arguments. + public static <T> ImmutableIterable<T> from(Iterable<T> iterable) { + return new ImmutableIterable<>(iterable); + } +} |