com.fasterxml.jackson.annotation

Annotation Type JsonValue

@Target(value={ANNOTATION_TYPE,METHOD})
@Retention(value=RUNTIME)
public @interface JsonValue

Marker annotation similar to XmlValue that indicates that results of the annotated "getter" method (which means signature must be that of getters; non-void return type, no args) is to be used as the single value to serialize for the instance. Usually value will be of a simple scalar type (String or Number), but it can be any serializable type (Collection, Map or Bean).

At most one method of a Class can be annotated with this annotation; if more than one is found, an exception may be thrown. Also, if method signature is not compatible with Getters, an exception may be thrown (whether exception is thrown or not is an implementation detail (due to filtering during introspection, some annotations may be skipped) and applications should not rely on specific behavior).

A typical usage is that of annotating toString() method so that returned String value is used as the JSON serialization; and if deserialization is needed, there is matching constructor or factory method annotated with JsonCreator annotation.

Boolean argument is only used so that sub-classes can "disable" annotation if necessary.

NOTE: when use for Java enums, one additional feature is that value returned by annotated method is also considered to be the value to deserialize from, not just JSON String to serialize as. This is possible since set of Enum values is constant and it is possible to define mapping, but can not be done in general for POJO types; as such, this is not used for POJO deserialization.

Optional Element Summary

Optional Elements

Modifier and Type	Optional Element and Description
boolean	value Optional argument that defines whether this annotation is active or not.

Element Detail

value

public abstract boolean value

Optional argument that defines whether this annotation is active or not. The only use for value 'false' if for overriding purposes. Overriding may be necessary when used with "mix-in annotations" (aka "annotation overrides"). For most cases, however, default value of "true" is just fine and should be omitted.

Default:

true