| /******************************************************************************* |
| * Copyright (c) 2016, 2018 Obeo. |
| * All rights reserved. This program and the accompanying materials |
| * are made available under the terms of the Eclipse Public License v2.0 |
| * which accompanies this distribution, and is available at |
| * https://www.eclipse.org/legal/epl-2.0 |
| * |
| * SPDX-License-Identifier: EPL-2.0 |
| * |
| * Contributors: Obeo - initial API and implementation |
| *******************************************************************************/ |
| package org.eclipse.eef.common.api.utils; |
| |
| import java.util.Arrays; |
| import java.util.Collection; |
| import java.util.Collections; |
| import java.util.stream.Collectors; |
| |
| /** |
| * Shared utility methods. |
| * |
| * @author Pierre-Charles David <pierre-charles.david@obeo.fr> |
| */ |
| public final class Util { |
| /** |
| * Prevent instantiation. |
| */ |
| private Util() { |
| // Prevent instantiation. |
| } |
| |
| /** |
| * Returns the first of a series of alternative string values which is not null. |
| * |
| * @param alternatives |
| * the alernative strings, in order of preference. |
| * @return the first non-null alternative, or an empty string if they are all null. |
| */ |
| public static String firstNonNull(String... alternatives) { |
| for (String s : alternatives) { |
| if (s != null) { |
| return s; |
| } |
| } |
| return null; |
| } |
| |
| /** |
| * Tests if a string is blank (i.e. null, empty, or containing only whitespace). |
| * |
| * @param s |
| * the string to test. |
| * @return <code>true</code> if and only if the string is blank. |
| */ |
| public static boolean isBlank(String s) { |
| return s == null || s.trim().length() == 0; |
| } |
| |
| /** |
| * Returns the given object as a collection and filter it with the given type. If the object is a single object, the |
| * we will return a collection containing said object, it the object is already a collection, we will return a new |
| * collection with all its elements. |
| * |
| * @param rawValue |
| * The raw value |
| * @param clazz |
| * The class of the result wanted |
| * @param <T> |
| * The type of the result wanted |
| * @return A collection |
| */ |
| public static <T> Collection<T> asCollection(Object rawValue, Class<T> clazz) { |
| final Collection<T> result; |
| if (rawValue instanceof Collection<?>) { |
| // @formatter:off |
| result = ((Collection<?>) rawValue).stream() |
| .filter(clazz::isInstance) |
| .map(clazz::cast) |
| .collect(Collectors.toList()); |
| // @formatter:on |
| } else if (clazz.isInstance(rawValue)) { |
| result = Collections.singleton(clazz.cast(rawValue)); |
| } else if (rawValue != null && rawValue.getClass().isArray()) { |
| // @formatter:off |
| result = Arrays.stream((Object[]) rawValue) |
| .filter(clazz::isInstance) |
| .map(clazz::cast) |
| .collect(Collectors.toList()); |
| // @formatter:on |
| } else { |
| result = Collections.emptySet(); |
| } |
| return result; |
| } |
| } |