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Diffstat (limited to 'src/main/java/org/apache/commons/lang3/function/FailablePredicate.java')
-rw-r--r-- | src/main/java/org/apache/commons/lang3/function/FailablePredicate.java | 104 |
1 files changed, 104 insertions, 0 deletions
diff --git a/src/main/java/org/apache/commons/lang3/function/FailablePredicate.java b/src/main/java/org/apache/commons/lang3/function/FailablePredicate.java new file mode 100644 index 000000000..bf4a5e370 --- /dev/null +++ b/src/main/java/org/apache/commons/lang3/function/FailablePredicate.java @@ -0,0 +1,104 @@ +/* + * Licensed to the Apache Software Foundation (ASF) under one or more + * contributor license agreements. See the NOTICE file distributed with + * this work for additional information regarding copyright ownership. + * The ASF licenses this file to You 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 org.apache.commons.lang3.function; + +import java.util.Objects; +import java.util.function.Predicate; + +/** + * A functional interface like {@link Predicate} that declares a {@link Throwable}. + * + * @param <T> Predicate type. + * @param <E> The kind of thrown exception or error. + * @since 3.11 + */ +@FunctionalInterface +public interface FailablePredicate<T, E extends Throwable> { + + /** FALSE singleton */ + @SuppressWarnings("rawtypes") + FailablePredicate FALSE = t -> false; + + /** TRUE singleton */ + @SuppressWarnings("rawtypes") + FailablePredicate TRUE = t -> true; + + /** + * Returns The FALSE singleton. + * + * @param <T> Predicate type. + * @param <E> The kind of thrown exception or error. + * @return The NOP singleton. + */ + static <T, E extends Throwable> FailablePredicate<T, E> falsePredicate() { + return FALSE; + } + + /** + * Returns The TRUE singleton. + * + * @param <T> Predicate type. + * @param <E> The kind of thrown exception or error. + * @return The NOP singleton. + */ + static <T, E extends Throwable> FailablePredicate<T, E> truePredicate() { + return TRUE; + } + + /** + * Returns a composed {@link FailablePredicate} like {@link Predicate#and(Predicate)}. + * + * @param other a predicate that will be logically-ANDed with this predicate. + * @return a composed {@link FailablePredicate} like {@link Predicate#and(Predicate)}. + * @throws NullPointerException if other is null + */ + default FailablePredicate<T, E> and(final FailablePredicate<? super T, E> other) { + Objects.requireNonNull(other); + return t -> test(t) && other.test(t); + } + + /** + * Returns a predicate that negates this predicate. + * + * @return a predicate that negates this predicate. + */ + default FailablePredicate<T, E> negate() { + return t -> !test(t); + } + + /** + * Returns a composed {@link FailablePredicate} like {@link Predicate#and(Predicate)}. + * + * @param other a predicate that will be logically-ORed with this predicate. + * @return a composed {@link FailablePredicate} like {@link Predicate#and(Predicate)}. + * @throws NullPointerException if other is null + */ + default FailablePredicate<T, E> or(final FailablePredicate<? super T, E> other) { + Objects.requireNonNull(other); + return t -> test(t) || other.test(t); + } + + /** + * Tests the predicate. + * + * @param object the object to test the predicate on + * @return the predicate's evaluation + * @throws E if the predicate fails + */ + boolean test(T object) throws E; +} |