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Han-Wen Nienhuysd08b27f2015-02-25 16:45:20 +01001// Copyright 2014 Google Inc. All rights reserved.
2//
3// Licensed under the Apache License, Version 2.0 (the "License");
4// you may not use this file except in compliance with the License.
5// You may obtain a copy of the License at
6//
7// http://www.apache.org/licenses/LICENSE-2.0
8//
9// Unless required by applicable law or agreed to in writing, software
10// distributed under the License is distributed on an "AS IS" BASIS,
11// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12// See the License for the specific language governing permissions and
13// limitations under the License.
14
15package com.google.devtools.build.lib.analysis;
16
17import com.google.common.base.Preconditions;
18import com.google.common.collect.ImmutableMap;
19import com.google.common.collect.UnmodifiableIterator;
20import com.google.devtools.build.lib.concurrent.ThreadSafety.Immutable;
21
22import java.util.LinkedHashMap;
23import java.util.Map;
24
25/**
26 * Extra information about a configured target computed on request of a dependent.
27 *
28 * <p>Analogous to {@link ConfiguredTarget}: contains a bunch of transitive info providers, which
29 * are merged with the providers of the associated configured target before they are passed to
30 * the configured target factories that depend on the configured target to which this aspect is
31 * added.
32 *
33 * <p>Aspects are created alongside configured targets on request from dependents.
34 */
35@Immutable
36public final class Aspect implements Iterable<TransitiveInfoProvider> {
37 private final
38 ImmutableMap<Class<? extends TransitiveInfoProvider>, TransitiveInfoProvider> providers;
39
40 private Aspect(
41 ImmutableMap<Class<? extends TransitiveInfoProvider>, TransitiveInfoProvider> providers) {
42 this.providers = providers;
43 }
44
45 /**
46 * Returns the providers created by the aspect.
47 */
48 public ImmutableMap<Class<? extends TransitiveInfoProvider>, TransitiveInfoProvider>
49 getProviders() {
50 return providers;
51 }
52
53 @Override
54 public UnmodifiableIterator<TransitiveInfoProvider> iterator() {
55 return providers.values().iterator();
56 }
57
58 /**
59 * Builder for {@link Aspect}.
60 */
61 public static class Builder {
62 private final Map<Class<? extends TransitiveInfoProvider>, TransitiveInfoProvider>
63 providers = new LinkedHashMap<>();
64
65 /**
66 * Adds a provider to the aspect.
67 */
68 public Builder addProvider(
69 Class<? extends TransitiveInfoProvider> key, TransitiveInfoProvider value) {
70 Preconditions.checkNotNull(key);
71 Preconditions.checkNotNull(value);
72 AnalysisUtils.checkProvider(key);
73 Preconditions.checkState(!providers.containsKey(key));
74 providers.put(key, value);
75 return this;
76 }
77
78 public Aspect build() {
79 return new Aspect(ImmutableMap.copyOf(providers));
80 }
81 }
82}