1 /*
2 * Copyright (C) 2012 The Guava Authors
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except
5 * in compliance with the License. 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 distributed under the License
10 * is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
11 * or implied. See the License for the specific language governing permissions and limitations under
12 * the License.
13 */
14
15 package com.google.common.reflect;
16
17 import static com.google.common.base.Preconditions.checkNotNull;
18
19 import com.google.common.annotations.Beta;
20 import com.google.common.collect.FluentIterable;
21 import com.google.common.collect.ImmutableList;
22 import java.lang.annotation.Annotation;
23 import java.lang.reflect.AnnotatedElement;
24 import java.lang.reflect.AnnotatedType;
25 import javax.annotation.CheckForNull;
26
27 /**
28 * Represents a method or constructor parameter.
29 *
30 * @author Ben Yu
31 * @since 14.0
32 */
33 @Beta
34 @ElementTypesAreNonnullByDefault
35 public final class Parameter implements AnnotatedElement {
36
37 private final Invokable<?, ?> declaration;
38 private final int position;
39 private final TypeToken<?> type;
40 private final ImmutableList<Annotation> annotations;
41 private final AnnotatedType annotatedType;
42
43 Parameter(
44 Invokable<?, ?> declaration,
45 int position,
46 TypeToken<?> type,
47 Annotation[] annotations,
48 AnnotatedType annotatedType) {
49 this.declaration = declaration;
50 this.position = position;
51 this.type = type;
52 this.annotations = ImmutableList.copyOf(annotations);
53 this.annotatedType = annotatedType;
54 }
55
56 /** Returns the type of the parameter. */
57 public TypeToken<?> getType() {
58 return type;
59 }
60
61 /** Returns the {@link Invokable} that declares this parameter. */
62 public Invokable<?, ?> getDeclaringInvokable() {
63 return declaration;
64 }
65
66 @Override
67 public boolean isAnnotationPresent(Class<? extends Annotation> annotationType) {
68 return getAnnotation(annotationType) != null;
69 }
70
71 @Override
72 @CheckForNull
73 public <A extends Annotation> A getAnnotation(Class<A> annotationType) {
74 checkNotNull(annotationType);
75 for (Annotation annotation : annotations) {
76 if (annotationType.isInstance(annotation)) {
77 return annotationType.cast(annotation);
78 }
79 }
80 return null;
81 }
82
83 @Override
84 public Annotation[] getAnnotations() {
85 return getDeclaredAnnotations();
86 }
87
88 /** @since 18.0 */
89 // @Override on JDK8
90 @Override
91 public <A extends Annotation> A[] getAnnotationsByType(Class<A> annotationType) {
92 return getDeclaredAnnotationsByType(annotationType);
93 }
94
95 /** @since 18.0 */
96 // @Override on JDK8
97 @Override
98 public Annotation[] getDeclaredAnnotations() {
99 return annotations.toArray(new Annotation[0]);
100 }
101
102 /** @since 18.0 */
103 // @Override on JDK8
104 @Override
105 @CheckForNull
106 public <A extends Annotation> A getDeclaredAnnotation(Class<A> annotationType) {
107 checkNotNull(annotationType);
108 return FluentIterable.from(annotations).filter(annotationType).first().orNull();
109 }
110
111 /** @since 18.0 */
112 // @Override on JDK8
113 @Override
114 public <A extends Annotation> A[] getDeclaredAnnotationsByType(Class<A> annotationType) {
115 return FluentIterable.from(annotations).filter(annotationType).toArray(annotationType);
116 }
117
118 /** @since 25.1 */
119 // @Override on JDK8
120 public AnnotatedType getAnnotatedType() {
121 return annotatedType;
122 }
123
124 @Override
125 public boolean equals(@CheckForNull Object obj) {
126 if (obj instanceof Parameter) {
127 Parameter that = (Parameter) obj;
128 return position == that.position && declaration.equals(that.declaration);
129 }
130 return false;
131 }
132
133 @Override
134 public int hashCode() {
135 return position;
136 }
137
138 @Override
139 public String toString() {
140 return type + " arg" + position;
141 }
142 }