com.google.inject.internal.DeclaredMembers Maven / Gradle / Ivy
/*
* Copyright (C) 2019 Google Inc.
*
* 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.inject.internal;
import com.google.common.collect.Ordering;
import java.lang.reflect.Field;
import java.lang.reflect.Method;
import java.util.Arrays;
import java.util.Comparator;
/**
* Utility class for retrieving declared fields or methods in a particular order, because the JVM
* doesn't guarantee ordering for listing declared methods. We don't externally guarantee an
* ordering, but having a consistent ordering allows deterministic behavior and simpler tests.
*
* For class ordering, within a single classloader there can only be one class with a given name,
* so we just compare the names.
*
*
For method ordering, within a single class it is sufficient to compare the non-generic method
* signature which consists of the name, return type and parameter types.
*/
public final class DeclaredMembers {
private DeclaredMembers() {}
public static Field[] getDeclaredFields(Class type) {
return Arrays.stream(type.getDeclaredFields())
.sorted(
Comparator.comparing(Field::getName)
.thenComparing(Field::getType, Comparator.comparing(Class::getName)))
.toArray(Field[]::new);
}
public static Method[] getDeclaredMethods(Class type) {
return Arrays.stream(type.getDeclaredMethods())
.sorted(
Comparator.comparing(Method::getName)
.thenComparing(Method::getReturnType, Comparator.comparing(Class::getName))
.thenComparing(
method -> Arrays.asList(method.getParameterTypes()),
// TODO: use Comparators.lexicographical when it's not @Beta.
Ordering.>from(Comparator.comparing(Class::getName))
.lexicographical()))
.toArray(Method[]::new);
}
}