Predicate.java
/*
* Copyright 2019 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 androidx.core.util;
import android.annotation.SuppressLint;
import java.util.Objects;
/**
* Compat version of {@link java.util.function.Predicate}
*
* @param <T> the type of the input to the operation
*/
@SuppressLint("UnknownNullness")
@SuppressWarnings("MissingNullability")
public interface Predicate<T> {
/**
* Evaluates this predicate on the given argument.
*
* @param t the input argument
* @return {@code true} if the input argument matches the predicate,
* otherwise {@code false}
*/
boolean test(T t);
/**
* Returns a composed predicate that represents a short-circuiting logical
* AND of this predicate and another. When evaluating the composed
* predicate, if this predicate is {@code false}, then the {@code other}
* predicate is not evaluated.
*
* <p>Any exceptions thrown during evaluation of either predicate are relayed
* to the caller; if evaluation of this predicate throws an exception, the
* {@code other} predicate will not be evaluated.
*
* @param other a predicate that will be logically-ANDed with this
* predicate
* @return a composed predicate that represents the short-circuiting logical
* AND of this predicate and the {@code other} predicate
* @throws NullPointerException if other is null
*/
@SuppressLint("MissingNullability")
default Predicate<T> and(@SuppressLint("MissingNullability") Predicate<? super T> other) {
Objects.requireNonNull(other);
return (t) -> test(t) && other.test(t);
}
/**
* Returns a predicate that represents the logical negation of this
* predicate.
*
* @return a predicate that represents the logical negation of this
* predicate
*/
@SuppressLint("MissingNullability")
default Predicate<T> negate() {
return (t) -> !test(t);
}
/**
* Returns a composed predicate that represents a short-circuiting logical
* OR of this predicate and another. When evaluating the composed
* predicate, if this predicate is {@code true}, then the {@code other}
* predicate is not evaluated.
*
* <p>Any exceptions thrown during evaluation of either predicate are relayed
* to the caller; if evaluation of this predicate throws an exception, the
* {@code other} predicate will not be evaluated.
*
* @param other a predicate that will be logically-ORed with this
* predicate
* @return a composed predicate that represents the short-circuiting logical
* OR of this predicate and the {@code other} predicate
* @throws NullPointerException if other is null
*/
@SuppressLint("MissingNullability")
default Predicate<T> or(@SuppressLint("MissingNullability") Predicate<? super T> other) {
Objects.requireNonNull(other);
return (t) -> test(t) || other.test(t);
}
/**
* Returns a predicate that tests if two arguments are equal according
* to {@link Objects#equals(Object, Object)}.
*
* @param <T> the type of arguments to the predicate
* @param targetRef the object reference with which to compare for equality,
* which may be {@code null}
* @return a predicate that tests if two arguments are equal according
* to {@link Objects#equals(Object, Object)}
*/
@SuppressLint("MissingNullability")
static <T> Predicate<T> isEqual(@SuppressLint("MissingNullability") Object targetRef) {
return (null == targetRef)
? object -> Objects.isNull(object)
: object -> targetRef.equals(object);
}
/**
* Returns a predicate that is the negation of the supplied predicate.
* This is accomplished by returning result of the calling
* {@code target.negate()}.
*
* @param <T> the type of arguments to the specified predicate
* @param target predicate to negate
* @return a predicate that negates the results of the supplied
* predicate
* @throws NullPointerException if target is null
* @since 11
*/
@SuppressWarnings("unchecked")
@SuppressLint("MissingNullability")
static <T> Predicate<T> not(@SuppressLint("MissingNullability") Predicate<? super T> target) {
Objects.requireNonNull(target);
return (Predicate<T>) target.negate();
}
}