|  | // Copyright 2014 The Bazel Authors. 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.actions; | 
|  |  | 
|  | import com.google.common.annotations.VisibleForTesting; | 
|  | import com.google.devtools.build.lib.cmdline.Label; | 
|  |  | 
|  | /** | 
|  | * An interface for {@code LabelAndConfiguration}, or at least for a {@link Label}. Only tests and | 
|  | * internal {@link Artifact}-generators should implement this interface -- otherwise, | 
|  | * {@code LabelAndConfiguration} should be the only implementation. | 
|  | */ | 
|  | public interface ArtifactOwner { | 
|  | Label getLabel(); | 
|  |  | 
|  | @VisibleForTesting | 
|  | public static final ArtifactOwner NULL_OWNER = new ArtifactOwner() { | 
|  | @Override | 
|  | public Label getLabel() { | 
|  | return null; | 
|  | } | 
|  |  | 
|  | @Override | 
|  | public String toString() { | 
|  | return "NULL_OWNER"; | 
|  | } | 
|  | }; | 
|  | } |