diff options
Diffstat (limited to 'src/tools/xcode-common/java/com/google/devtools/build/xcode/util/Equaling.java')
-rw-r--r-- | src/tools/xcode-common/java/com/google/devtools/build/xcode/util/Equaling.java | 80 |
1 files changed, 80 insertions, 0 deletions
diff --git a/src/tools/xcode-common/java/com/google/devtools/build/xcode/util/Equaling.java b/src/tools/xcode-common/java/com/google/devtools/build/xcode/util/Equaling.java new file mode 100644 index 0000000000..c359e57056 --- /dev/null +++ b/src/tools/xcode-common/java/com/google/devtools/build/xcode/util/Equaling.java @@ -0,0 +1,80 @@ +// Copyright 2014 Google Inc. 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 static com.google.common.base.Preconditions.checkNotNull; + +import com.google.common.base.Optional; + +import java.io.File; +import java.nio.file.Path; +import java.util.List; +import java.util.Set; + +/** + * Provides utility methods that make equality comparison type safe. The + * {@link Object#equals(Object)} method usually returns false when the other object is {@code null} + * or a different runtime class. These utility methods try to force each object to be of the same + * class (with the method signatures) and non-null (and throwing a {@link NullPointerException} if + * either one is null. + */ +public class Equaling { + private Equaling() { + throw new UnsupportedOperationException("static-only"); + } + + // Note that we always checkNotNull(b) on a separate line from a.equals(b). This is to make it so + // the stack trace will tell you exactly which reference is null. + + public static <T extends Value<T>> boolean of(Value<T> a, Value<T> b) { + checkNotNull(b); + return a.equals(b); + } + + public static boolean of(String a, String b) { + checkNotNull(b); + return a.equals(b); + } + + public static <T> boolean of(Optional<T> a, Optional<T> b) { + checkNotNull(b); + return a.equals(b); + } + + public static <T> boolean of(Set<T> a, Set<T> b) { + checkNotNull(b); + return a.equals(b); + } + + public static boolean of(File a, File b) { + checkNotNull(b); + return a.equals(b); + } + + public static boolean of(Path a, Path b) { + checkNotNull(b); + return a.equals(b); + } + + public static <T> boolean of(List<T> a, List<T> b) { + checkNotNull(b); + return a.equals(b); + } + + public static <T extends Enum<T>> boolean of(Enum<T> a, Enum<T> b) { + checkNotNull(b); + return a.equals(b); + } +} |