Created
March 6, 2015 00:21
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The Java Enum for REST/JSON API
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import com.fasterxml.jackson.annotation.JsonCreator; | |
import com.fasterxml.jackson.annotation.JsonValue; | |
/** | |
* @author Ramesh Dara | |
*/ | |
public class enumDemo { | |
public static void main(String[] args) { | |
getEnumFromString(Directions.class, "North"); | |
getEnumFromString(Directions.class, "North-East"); | |
} | |
public static <T extends Enum<T>> T getEnumFromString(Class<T> enumClass, String value) { | |
if (enumClass == null) { | |
throw new IllegalArgumentException("EnumClass value can't be null."); | |
} | |
for (Enum<?> enumValue : enumClass.getEnumConstants()) { | |
if (enumValue.toString().equalsIgnoreCase(value)) { | |
return (T) enumValue; | |
} | |
} | |
//Construct an error message that indicates all possible values for the enum. | |
StringBuilder errorMessage = new StringBuilder(); | |
boolean bFirstTime = true; | |
for (Enum<?> enumValue : enumClass.getEnumConstants()) { | |
errorMessage.append(bFirstTime ? "" : ", ").append(enumValue); | |
bFirstTime = false; | |
} | |
throw new IllegalArgumentException(value + " is invalid value. Supported values are " + errorMessage); | |
} | |
public enum Directions { | |
NORTH, | |
SOUTH, | |
EAST, | |
WEST; | |
@JsonCreator | |
public static Directions fromValue(String value) { | |
return getEnumFromString(Directions.class, value); | |
} | |
@JsonValue | |
public String toJson() { | |
return name().toLowerCase(); | |
} | |
} | |
} |
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