1/**
2 * Copyright (C) 2008 Google Inc.
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17package com.google.inject.spi;
18
19/**
20 * Visits each of the strategies used to find an instance to satisfy an injection.
21 *
22 * @param <V> any type to be returned by the visit method. Use {@link Void} with
23 *     {@code return null} if no return type is needed.
24 * @since 2.0
25 */
26public interface BindingTargetVisitor<T, V> {
27
28  /**
29   * Visit a instance binding. The same instance is returned for every injection. This target is
30   * found in both module and injector bindings.
31   */
32  V visit(InstanceBinding<? extends T> binding);
33
34  /**
35   * Visit a provider instance binding. The provider's {@code get} method is invoked to resolve
36   * injections. This target is found in both module and injector bindings.
37   */
38  V visit(ProviderInstanceBinding<? extends T> binding);
39
40  /**
41   * Visit a provider key binding. To resolve injections, the provider key is first resolved, then
42   * that provider's {@code get} method is invoked. This target is found in both module and injector
43   * bindings.
44   */
45  V visit(ProviderKeyBinding<? extends T> binding);
46
47  /**
48   * Visit a linked key binding. The other key's binding is used to resolve injections. This
49   * target is found in both module and injector bindings.
50   */
51  V visit(LinkedKeyBinding<? extends T> binding);
52
53  /**
54   * Visit a binding to a key exposed from an enclosed private environment. This target is only
55   * found in injector bindings.
56   */
57  V visit(ExposedBinding<? extends T> binding);
58
59  /**
60   * Visit an untargetted binding. This target is found only on module bindings. It indicates
61   * that the injector should use its implicit binding strategies to resolve injections.
62   */
63  V visit(UntargettedBinding<? extends T> binding);
64
65  /**
66   * Visit a constructor binding. To resolve injections, an instance is instantiated by invoking
67   * {@code constructor}. This target is found only on injector bindings.
68   */
69  V visit(ConstructorBinding<? extends T> binding);
70
71  /**
72   * Visit a binding created from converting a bound instance to a new type. The source binding
73   * has the same binding annotation but a different type. This target is found only on injector
74   * bindings.
75   */
76  V visit(ConvertedConstantBinding<? extends T> binding);
77
78  /**
79   * Visit a binding to a {@link com.google.inject.Provider} that delegates to the binding for the
80   * provided type. This target is found only on injector bindings.
81   */
82  V visit(ProviderBinding<? extends T> binding);
83}
84