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Java example source code file (Enums.java)
The Enums.java Java example source code/* * Copyright (C) 2011 The Guava Authors * * 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.common.base; import static com.google.common.base.Preconditions.checkNotNull; import com.google.common.annotations.Beta; import com.google.common.annotations.GwtCompatible; import com.google.common.annotations.GwtIncompatible; import java.io.Serializable; import java.lang.ref.WeakReference; import java.lang.reflect.Field; import java.util.EnumSet; import java.util.HashMap; import java.util.Map; import java.util.WeakHashMap; import javax.annotation.Nullable; /** * Utility methods for working with {@link Enum} instances. * * @author Steve McKay * * @since 9.0 */ @GwtCompatible(emulated = true) @Beta public final class Enums { private Enums() {} /** * Returns the {@link Field} in which {@code enumValue} is defined. For example, to get the * {@code Description} annotation on the {@code GOLF} constant of enum {@code Sport}, use * {@code Enums.getField(Sport.GOLF).getAnnotation(Description.class)}. * * @since 12.0 */ @GwtIncompatible // reflection public static Field getField(Enum<?> enumValue) { Class<?> clazz = enumValue.getDeclaringClass(); try { return clazz.getDeclaredField(enumValue.name()); } catch (NoSuchFieldException impossible) { throw new AssertionError(impossible); } } /** * Returns an optional enum constant for the given type, using {@link Enum#valueOf}. If the * constant does not exist, {@link Optional#absent} is returned. A common use case is for parsing * user input or falling back to a default enum constant. For example, * {@code Enums.getIfPresent(Country.class, countryInput).or(Country.DEFAULT);} * * @since 12.0 */ public static <T extends Enum Other Java examples (source code examples)Here is a short list of links related to this Java Enums.java source code file: |
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