| // Copyright 2014 The Bazel Authors. All rights reserved. |
| // |
| // 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 com.google.devtools.build.xcode.util; |
| |
| import com.google.common.base.Optional; |
| import com.google.common.base.Preconditions; |
| |
| import java.util.Map; |
| |
| /** |
| * Provides utility methods that make map lookup safe. |
| */ |
| public class Mapping { |
| private Mapping() { |
| throw new UnsupportedOperationException("static-only"); |
| } |
| |
| /** |
| * Returns the value mapped to the given key for a map. If the mapping is not present, an absent |
| * {@code Optional} is returned. |
| * @throws NullPointerException if the map or key argument is null |
| */ |
| public static <K, V> Optional<V> of(Map<K, V> map, K key) { |
| Preconditions.checkNotNull(key); |
| return Optional.fromNullable(map.get(key)); |
| } |
| } |