();
51 |
52 | /**
53 | * Creates an injector defined by {@code modules} and immediately uses it to
54 | * create an instance of {@code type}. The modules can be of any type, and
55 | * must contain {@code @Provides} methods.
56 | *
57 | * The following injection features are supported:
58 | *
59 | * - Field injection. A class may have any number of field injections, and
60 | * fields may be of any visibility. Static fields will be injected each
61 | * time an instance is injected.
62 | *
- Constructor injection. A class may have a single {@code
63 | * @Inject}-annotated constructor. Classes that have fields injected
64 | * may omit the {@link @Inject} annotation if they have a public
65 | * no-arguments constructor.
66 | *
- Injection of {@code @Provides} method parameters.
67 | *
- {@code @Provides} methods annotated {@code @Singleton}.
68 | *
- Constructor-injected classes annotated {@code @Singleton}.
69 | *
- Injection of {@link Provider}s.
70 | *
- Binding annotations on injected parameters and fields.
71 | *
- Guice annotations.
72 | *
- JSR 330 annotations.
73 | *
- Eager loading of singletons.
74 | *
75 | *
76 | * Note that method injection is not supported.
77 | */
78 | public static T inject(Class type, boolean fallbackToDefaultConstructor, Object... modules) {
79 | Key key = new Key(type, null);
80 | MiniGuice miniGuice = new MiniGuice();
81 | for (Object module : modules) {
82 | miniGuice.install(module);
83 | }
84 | miniGuice.requireKey(key, "root injection");
85 | miniGuice.addJitBindings(fallbackToDefaultConstructor);
86 | miniGuice.addProviderBindings();
87 | miniGuice.eagerlyLoadSingletons();
88 | Provider provider = miniGuice.bindings.get(key);
89 | return type.cast(provider.get());
90 | }
91 |
92 | private void addProviderBindings() {
93 | Map> providerBindings = new HashMap>();
94 | for (final Map.Entry> binding : bindings.entrySet()) {
95 | Key key = binding.getKey();
96 | final Provider value = binding.getValue();
97 | Provider> providerProvider = new Provider>() {
98 | public Provider get() {
99 | return value;
100 | }
101 | };
102 | providerBindings.put(new Key(new ProviderType(javax.inject.Provider.class, key.type),
103 | key.annotation), providerProvider);
104 | }
105 | bindings.putAll(providerBindings);
106 | }
107 |
108 | private void requireKey(Key key, Object requiredBy) {
109 | if (key.type instanceof ParameterizedType
110 | && (((ParameterizedType) key.type).getRawType() == Provider.class
111 | || ((ParameterizedType) key.type).getRawType() == javax.inject.Provider.class)) {
112 | Type type = ((ParameterizedType) key.type).getActualTypeArguments()[0];
113 | key = new Key(type, key.annotation);
114 | }
115 |
116 | requiredKeys.add(new RequiredKey(key, requiredBy));
117 | }
118 |
119 | private void eagerlyLoadSingletons() {
120 | for (Key key : singletons) {
121 | Provider provider = bindings.get(key);
122 | final Object onlyInstance = provider.get();
123 | bindings.put(key, new Provider