1 /* 2 * Copyright (C) 2012 The Guava Authors 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.common.reflect; 18 19 import static com.google.common.base.Preconditions.checkNotNull; 20 21 import com.google.common.annotations.Beta; 22 import com.google.common.collect.FluentIterable; 23 import com.google.common.collect.ImmutableList; 24 25 import java.lang.annotation.Annotation; 26 import java.lang.reflect.AnnotatedElement; 27 28 import javax.annotation.Nullable; 29 30 /** 31 * Represents a method or constructor parameter. 32 * 33 * @author Ben Yu 34 * @since 14.0 35 */ 36 @Beta 37 public final class Parameter implements AnnotatedElement { 38 39 private final Invokable<?, ?> declaration; 40 private final int position; 41 private final TypeToken<?> type; 42 private final ImmutableList<Annotation> annotations; 43 Parameter( Invokable<?, ?> declaration, int position, TypeToken<?> type, Annotation[] annotations)44 Parameter( 45 Invokable<?, ?> declaration, 46 int position, 47 TypeToken<?> type, 48 Annotation[] annotations) { 49 this.declaration = declaration; 50 this.position = position; 51 this.type = type; 52 this.annotations = ImmutableList.copyOf(annotations); 53 } 54 55 /** Returns the type of the parameter. */ getType()56 public TypeToken<?> getType() { 57 return type; 58 } 59 60 /** Returns the {@link Invokable} that declares this parameter. */ getDeclaringInvokable()61 public Invokable<?, ?> getDeclaringInvokable() { 62 return declaration; 63 } 64 isAnnotationPresent(Class<? extends Annotation> annotationType)65 @Override public boolean isAnnotationPresent(Class<? extends Annotation> annotationType) { 66 return getAnnotation(annotationType) != null; 67 } 68 69 @Override 70 @Nullable getAnnotation(Class<A> annotationType)71 public <A extends Annotation> A getAnnotation(Class<A> annotationType) { 72 checkNotNull(annotationType); 73 for (Annotation annotation : annotations) { 74 if (annotationType.isInstance(annotation)) { 75 return annotationType.cast(annotation); 76 } 77 } 78 return null; 79 } 80 getAnnotations()81 @Override public Annotation[] getAnnotations() { 82 return getDeclaredAnnotations(); 83 } 84 85 /** 86 * @since 18.0 87 */ 88 // @Override on JDK8 getAnnotationsByType(Class<A> annotationType)89 public <A extends Annotation> A[] getAnnotationsByType(Class<A> annotationType) { 90 return getDeclaredAnnotationsByType(annotationType); 91 } 92 93 /** 94 * @since 18.0 95 */ 96 // @Override on JDK8 getDeclaredAnnotations()97 @Override public Annotation[] getDeclaredAnnotations() { 98 return annotations.toArray(new Annotation[annotations.size()]); 99 } 100 101 /** 102 * @since 18.0 103 */ 104 // @Override on JDK8 105 @Nullable getDeclaredAnnotation(Class<A> annotationType)106 public <A extends Annotation> A getDeclaredAnnotation(Class<A> annotationType) { 107 checkNotNull(annotationType); 108 return FluentIterable.from(annotations) 109 .filter(annotationType) 110 .first() 111 .orNull(); 112 } 113 114 /** 115 * @since 18.0 116 */ 117 // @Override on JDK8 118 public <A extends Annotation> A[] getDeclaredAnnotationsByType(Class<A> annotationType)119 getDeclaredAnnotationsByType(Class<A> annotationType) { 120 return FluentIterable.from(annotations) 121 .filter(annotationType) 122 .toArray(annotationType); 123 } 124 equals(@ullable Object obj)125 @Override public boolean equals(@Nullable 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 hashCode()133 @Override public int hashCode() { 134 return position; 135 } 136 toString()137 @Override public String toString() { 138 return type + " arg" + position; 139 } 140 } 141