Created
July 10, 2019 17:14
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| import java.util.EnumSet; | |
| import java.util.Objects; | |
| import java.util.Optional; | |
| import java.util.function.Function; | |
| public class Enums { | |
| public static <E extends Enum<E>, T> Optional<E> lookup(Class<E> elementType, Function<E, T> extractor, T value) { | |
| return EnumSet.allOf(elementType).stream() | |
| .filter(candidate -> Objects.equals(extractor.apply(candidate), value)).findFirst(); | |
| } | |
| } | |
| enum MyEnum { | |
| CONSTANT_NAME("constant name"); | |
| private final String constantName; | |
| MyEnum(String contantName) { | |
| this.constantName = contantName; | |
| } | |
| public static Optional<MyEnum> byConstantName(String name) { | |
| return Enums.lookup(MyEnum.class, f -> f.constantName, name); | |
| } | |
| } |
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