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A library jar that provides APIs for Applications written for the Google Android Platform.
/*
* 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.
*/
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 Predicate and(Predicate... components) {
return 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 Predicate and(Iterable> 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 Predicate or(Predicate... components) {
return 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 Predicate or(Iterable> components) {
return new OrPredicate(components);
}
/**
* Returns a Predicate that evaluates to true iff the given Predicate
* evaluates to false.
*/
public static Predicate not(Predicate predicate) {
return new NotPredicate(predicate);
}
private static class AndPredicate implements Predicate {
private final Iterable> components;
private AndPredicate(Iterable> components) {
this.components = components;
}
public boolean apply(T t) {
for (Predicate predicate : components) {
if (!predicate.apply(t)) {
return false;
}
}
return true;
}
}
private static class OrPredicate implements Predicate {
private final Iterable> components;
private OrPredicate(Iterable> components) {
this.components = components;
}
public boolean apply(T t) {
for (Predicate predicate : components) {
if (predicate.apply(t)) {
return true;
}
}
return false;
}
}
private static class NotPredicate implements Predicate {
private final Predicate predicate;
private NotPredicate(Predicate predicate) {
this.predicate = predicate;
}
public boolean apply(T t) {
return !predicate.apply(t);
}
}
}