com.sun.enterprise.universal.JavaLangUtils Maven / Gradle / Ivy
/*
* Copyright (c) 2022 Eclipse Foundation and/or its affiliates. All rights reserved.
*
* This program and the accompanying materials are made available under the
* terms of the Eclipse Public License v. 2.0, which is available at
* http://www.eclipse.org/legal/epl-2.0.
*
* This Source Code may also be made available under the following Secondary
* Licenses when the conditions for such availability set forth in the
* Eclipse Public License v. 2.0 are satisfied: GNU General Public License,
* version 2 with the GNU Classpath Exception, which is available at
* https://www.gnu.org/software/classpath/license.html.
*
* SPDX-License-Identifier: EPL-2.0 OR GPL-2.0 WITH Classpath-exception-2.0
*/
package com.sun.enterprise.universal;
import java.util.function.Function;
import java.util.function.Supplier;
/**
* Utility class for all trivial functions missing in Java.
*
* @author David Matejcek
*/
public final class JavaLangUtils {
private JavaLangUtils() {
// utility class
}
/**
* If the value is null, calls the supplier to obtain the default value.
*
* @param expected type
* @param value provided value
* @param supplierOfDefault must not be null.
* @return value OR value provided by the supplier. Note that it may be null too.
*/
public static T nonNull(T value, Supplier supplierOfDefault) {
return value == null ? supplierOfDefault.get() : value;
}
/**
* If the value is null, calls the supplier to obtain the default value.
*
* If the value is not null, applies the function.
*
* @param input value type
* @param expected type
* @param value provided value - can be null
* @param function function to apply to the value. Must not be null.
* @param supplierOfDefault can be null, then supplies null.
* @return result of a function OR value provided by the supplier. Note that the returned value
* may be null too.
*/
public static T nonNull(V value, Function function, Supplier supplierOfDefault) {
if (value == null) {
return supplierOfDefault == null ? null : supplierOfDefault.get();
}
return function.apply(value);
}
}