| /* |
| * Copyright (C) 2008 The Android Open Source Project |
| * |
| * 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.android.internal.util; |
| |
| import java.util.Arrays; |
| |
| /** |
| * Predicates contains static methods for creating the standard set of |
| * {@code Predicate} objects. |
| * |
| * @hide |
| */ |
| public class Predicates { |
| |
| private Predicates() { |
| } |
| |
| /** |
| * Returns a Predicate that evaluates to true iff each of its components |
| * evaluates to true. The components are evaluated in order, and evaluation |
| * will be "short-circuited" as soon as the answer is determined. |
| */ |
| public static <T> Predicate<T> and(Predicate<? super T>... components) { |
| return Predicates.<T>and(Arrays.asList(components)); |
| } |
| |
| /** |
| * Returns a Predicate that evaluates to true iff each of its components |
| * evaluates to true. The components are evaluated in order, and evaluation |
| * will be "short-circuited" as soon as the answer is determined. Does not |
| * defensively copy the iterable passed in, so future changes to it will alter |
| * the behavior of this Predicate. If components is empty, the returned |
| * Predicate will always evaluate to true. |
| */ |
| public static <T> Predicate<T> and(Iterable<? extends Predicate<? super T>> components) { |
| return new AndPredicate(components); |
| } |
| |
| /** |
| * Returns a Predicate that evaluates to true iff any one of its components |
| * evaluates to true. The components are evaluated in order, and evaluation |
| * will be "short-circuited" as soon as the answer is determined. |
| */ |
| public static <T> Predicate<T> or(Predicate<? super T>... components) { |
| return Predicates.<T>or(Arrays.asList(components)); |
| } |
| |
| /** |
| * Returns a Predicate that evaluates to true iff any one of its components |
| * evaluates to true. The components are evaluated in order, and evaluation |
| * will be "short-circuited" as soon as the answer is determined. Does not |
| * defensively copy the iterable passed in, so future changes to it will alter |
| * the behavior of this Predicate. If components is empty, the returned |
| * Predicate will always evaluate to false. |
| */ |
| public static <T> Predicate<T> or(Iterable<? extends Predicate<? super T>> components) { |
| return new OrPredicate(components); |
| } |
| |
| /** |
| * Returns a Predicate that evaluates to true iff the given Predicate |
| * evaluates to false. |
| */ |
| public static <T> Predicate<T> not(Predicate<? super T> predicate) { |
| return new NotPredicate<T>(predicate); |
| } |
| |
| private static class AndPredicate<T> implements Predicate<T> { |
| private final Iterable<? extends Predicate<? super T>> components; |
| |
| private AndPredicate(Iterable<? extends Predicate<? super T>> components) { |
| this.components = components; |
| } |
| |
| public boolean apply(T t) { |
| for (Predicate<? super T> predicate : components) { |
| if (!predicate.apply(t)) { |
| return false; |
| } |
| } |
| return true; |
| } |
| } |
| |
| private static class OrPredicate<T> implements Predicate<T> { |
| private final Iterable<? extends Predicate<? super T>> components; |
| |
| private OrPredicate(Iterable<? extends Predicate<? super T>> components) { |
| this.components = components; |
| } |
| |
| public boolean apply(T t) { |
| for (Predicate<? super T> predicate : components) { |
| if (predicate.apply(t)) { |
| return true; |
| } |
| } |
| return false; |
| } |
| } |
| |
| private static class NotPredicate<T> implements Predicate<T> { |
| private final Predicate<? super T> predicate; |
| |
| private NotPredicate(Predicate<? super T> predicate) { |
| this.predicate = predicate; |
| } |
| |
| public boolean apply(T t) { |
| return !predicate.apply(t); |
| } |
| } |
| } |