com.google.common.reflect.Parameter Maven / Gradle / Ivy
/*
* Copyright (C) 2012 The Guava Authors
*
* Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except
* in compliance with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software distributed under the License
* is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
* or implied. See the License for the specific language governing permissions and limitations under
* the License.
*/
package com.google.common.reflect;
import static com.google.common.base.Preconditions.checkNotNull;
import static java.util.Objects.requireNonNull;
import com.google.common.collect.FluentIterable;
import com.google.common.collect.ImmutableList;
import java.lang.annotation.Annotation;
import java.lang.reflect.AnnotatedElement;
import java.lang.reflect.AnnotatedType;
import javax.annotation.CheckForNull;
import org.checkerframework.checker.nullness.qual.Nullable;
/**
* Represents a method or constructor parameter.
*
* @author Ben Yu
* @since 14.0
*/
@ElementTypesAreNonnullByDefault
public final class Parameter implements AnnotatedElement {
private final Invokable declaration;
private final int position;
private final TypeToken type;
private final ImmutableList annotations;
/**
* An {@code AnnotatedType} instance, or {@code null} under Android VMs (possible only when using
* the Android flavor of Guava). The field is declared with a type of {@code Object} to avoid
* compatibility problems on Android VMs. The corresponding accessor method, however, can have the
* more specific return type as long as users are careful to guard calls to it with version checks
* or reflection: Android VMs ignore the types of elements that aren't used.
*/
private final @Nullable Object annotatedType;
Parameter(
Invokable declaration,
int position,
TypeToken type,
Annotation[] annotations,
@Nullable Object annotatedType) {
this.declaration = declaration;
this.position = position;
this.type = type;
this.annotations = ImmutableList.copyOf(annotations);
this.annotatedType = annotatedType;
}
/** Returns the type of the parameter. */
public TypeToken getType() {
return type;
}
/** Returns the {@link Invokable} that declares this parameter. */
public Invokable getDeclaringInvokable() {
return declaration;
}
@Override
public boolean isAnnotationPresent(Class annotationType) {
return getAnnotation(annotationType) != null;
}
@Override
@CheckForNull
public A getAnnotation(Class annotationType) {
checkNotNull(annotationType);
for (Annotation annotation : annotations) {
if (annotationType.isInstance(annotation)) {
return annotationType.cast(annotation);
}
}
return null;
}
@Override
public Annotation[] getAnnotations() {
return getDeclaredAnnotations();
}
/**
* @since 18.0
*/
@Override
public A[] getAnnotationsByType(Class annotationType) {
return getDeclaredAnnotationsByType(annotationType);
}
/** @since 18.0 */
@Override
public Annotation[] getDeclaredAnnotations() {
return annotations.toArray(new Annotation[0]);
}
/**
* @since 18.0
*/
@Override
@CheckForNull
public A getDeclaredAnnotation(Class annotationType) {
checkNotNull(annotationType);
return FluentIterable.from(annotations).filter(annotationType).first().orNull();
}
/**
* @since 18.0
*/
@Override
public A[] getDeclaredAnnotationsByType(Class annotationType) {
@Nullable
A[] result = FluentIterable.from(annotations).filter(annotationType).toArray(annotationType);
@SuppressWarnings("nullness") // safe because the input list contains no nulls
A[] cast = (A[]) result;
return cast;
}
/**
* Returns the {@link AnnotatedType} of the parameter.
*
* @since 25.1 for guava-jre
*/
@SuppressWarnings("Java7ApiChecker")
public AnnotatedType getAnnotatedType() {
return requireNonNull((AnnotatedType) annotatedType);
}
@Override
public boolean equals(@CheckForNull Object obj) {
if (obj instanceof Parameter) {
Parameter that = (Parameter) obj;
return position == that.position && declaration.equals(that.declaration);
}
return false;
}
@Override
public int hashCode() {
return position;
}
@Override
public String toString() {
return type + " arg" + position;
}
}