| /** |
| * 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.waveprotocol.wave.model.util; |
| |
| /** |
| * Utilities related to the document-based value classes |
| * |
| * @author anorth@google.com (Alex North) |
| */ |
| public final class ValueUtils { |
| |
| /** |
| * @return true iff a and b are both null or are equal |
| */ |
| public static <T> boolean equal(T a, T b) { |
| return (a == null) ? (b == null) : a.equals(b); |
| } |
| |
| /** |
| * @return true iff a and b are not both null and are not equal |
| */ |
| public static <T> boolean notEqual(T a, T b) { |
| return (a == null) ? (b != null) : !a.equals(b); |
| } |
| |
| /** |
| * @return {@code value} if it is not null, {@code def} otherwise |
| */ |
| public static <T> T valueOrDefault(T value, T def) { |
| return value != null ? value : def; |
| } |
| |
| /** |
| * Returns the first {@code size} characters of the given string |
| */ |
| public static String abbrev(String longString, int size) { |
| if (longString == null) { |
| return null; |
| } |
| |
| return longString.length() <= size ? longString |
| : new String(longString.substring(0, size)); |
| } |
| } |