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 
17 package com.google.inject.spi;
18 
19 import com.google.inject.Binding;
20 
21 /**
22  * No-op visitor for subclassing. All interface methods simply delegate to
23  * {@link #visitOther(Element)}, returning its result.
24  *
25  * @param <V> any type to be returned by the visit method. Use {@link Void} with
26  *     {@code return null} if no return type is needed.
27  *
28  * @author sberlin@gmail.com (Sam Berlin)
29  * @since 2.0
30  */
31 public abstract class DefaultElementVisitor<V> implements ElementVisitor<V> {
32 
33   /**
34    * Default visit implementation. Returns {@code null}.
35    */
visitOther(Element element)36   protected V visitOther(Element element) {
37     return null;
38   }
39 
visit(Message message)40   public V visit(Message message) {
41     return visitOther(message);
42   }
43 
visit(Binding<T> binding)44   public <T> V visit(Binding<T> binding) {
45     return visitOther(binding);
46   }
47 
48   /*if[AOP]*/
visit(InterceptorBinding interceptorBinding)49   public V visit(InterceptorBinding interceptorBinding) {
50     return visitOther(interceptorBinding);
51   }
52   /*end[AOP]*/
53 
visit(ScopeBinding scopeBinding)54   public V visit(ScopeBinding scopeBinding) {
55     return visitOther(scopeBinding);
56   }
57 
visit(TypeConverterBinding typeConverterBinding)58   public V visit(TypeConverterBinding typeConverterBinding) {
59     return visitOther(typeConverterBinding);
60   }
61 
visit(ProviderLookup<T> providerLookup)62   public <T> V visit(ProviderLookup<T> providerLookup) {
63     return visitOther(providerLookup);
64   }
65 
visit(InjectionRequest<?> injectionRequest)66   public V visit(InjectionRequest<?> injectionRequest) {
67     return visitOther(injectionRequest);
68   }
69 
visit(StaticInjectionRequest staticInjectionRequest)70   public V visit(StaticInjectionRequest staticInjectionRequest) {
71     return visitOther(staticInjectionRequest);
72   }
73 
visit(PrivateElements privateElements)74   public V visit(PrivateElements privateElements) {
75     return visitOther(privateElements);
76   }
77 
visit(MembersInjectorLookup<T> lookup)78   public <T> V visit(MembersInjectorLookup<T> lookup) {
79     return visitOther(lookup);
80   }
81 
visit(TypeListenerBinding binding)82   public V visit(TypeListenerBinding binding) {
83     return visitOther(binding);
84   }
85 
visit(ProvisionListenerBinding binding)86   public V visit(ProvisionListenerBinding binding) {
87     return visitOther(binding);
88   }
89 
visit(DisableCircularProxiesOption option)90   public V visit(DisableCircularProxiesOption option) {
91     return visitOther(option);
92   }
93 
visit(RequireExplicitBindingsOption option)94   public V visit(RequireExplicitBindingsOption option) {
95     return visitOther(option);
96   }
97 
visit(RequireAtInjectOnConstructorsOption option)98   public V visit(RequireAtInjectOnConstructorsOption option) {
99     return visitOther(option);
100   }
101 
visit(RequireExactBindingAnnotationsOption option)102   public V visit(RequireExactBindingAnnotationsOption option) {
103     return visitOther(option);
104   }
105 
visit(ModuleAnnotatedMethodScannerBinding binding)106   public V visit(ModuleAnnotatedMethodScannerBinding binding) {
107     return visitOther(binding);
108   }
109 }
110