io.github.mletkin.numerobis.common.Util Maven / Gradle / Ivy
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/**
* (c) 2019 by Ullrich Rieger
*
* 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 io.github.mletkin.numerobis.common;
import java.io.File;
import java.nio.file.Path;
import java.util.Collection;
import java.util.function.Predicate;
import java.util.function.Supplier;
import java.util.stream.Stream;
/**
* General purpose utility methods.
*/
public final class Util {
private Util() {
// prevent instantiation
}
/**
* negate the given predicate.
*
* Prefix version of {@code Predicate.negate()}
*
* @param
* predicate parameter class
* @param predicate
* predicate to negate
* @return the negated predicate as {@code Predicate}
*/
public static Predicate not(Predicate predicate) {
return predicate.negate();
}
/**
* Throws an exception if the flag evaluates to false.
*
* @param
* Class of the exception to throw
* @param flag
* flag to evaluate
* @param supplier
* that produces the exception to be thrown
* @throws T
* thrown if {@code flag} is {@code false}
*/
public static void ifNotThrow(boolean flag, Supplier supplier) throws T {
if (!flag) {
throw supplier.get();
}
}
/**
* Checks whether a stream contains an object.
*
* @param stream
* Stream to checkxs
* @return {@code true} if the stream is not empty
*/
public static boolean exists(Stream stream) {
return stream.findAny().isPresent();
}
/**
* Returns a stream from a Collection (null save).
*
* @param
* class of the objects in the collection
* @param collection
* collection of objeccts
* @return stream of collection objects
*/
public static Stream stream(Collection collection) {
return collection == null ? Stream.empty() : collection.stream();
}
/**
* Create all non existing directories on the path of a file.
*
* @param destinationFile
* file with path
*/
public static void createParentPath(Path destinationFile) {
File parent = destinationFile.getParent().toFile();
if (!parent.exists() && !parent.mkdirs()) {
throw new IllegalStateException("Couldn't create dir: " + parent);
}
}
}