package com.fasterxml.jackson.annotation;
import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;
Marker annotation
that indicates that the value of annotated accessor (either field
or "getter" method [a method with non-void return type, no args])
is to be used as the single value to serialize for the instance,
instead of the usual method of collecting properties of value.
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 accessor of a Class can be annotated with this annotation;
if more than one is found, an exception may be thrown.
Also, if method signature of annotated method 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.
See Also:
/**
* Marker annotation
* that indicates that the value of annotated accessor (either field
* or "getter" method [a method with non-void return type, no args])
* is to be used as the single value to serialize for the instance,
* instead of the usual method of collecting properties of value.
* Usually value will be of a simple scalar type
* (String or Number), but it can be any serializable type (Collection,
* Map or Bean).
*<p>
* At most one accessor of a <code>Class</code> can be annotated with this annotation;
* if more than one is found, an exception may be thrown.
* Also, if method signature of annotated method 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).
*<p>
* A typical usage is that of annotating <code>toString()</code>
* 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 {@link JsonCreator} annotation.
*<p>
* Boolean argument is only used so that sub-classes can "disable"
* annotation if necessary.
*<p>
* NOTE: when use for Java <code>enum</code>s, 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.
*
* @see JsonCreator
*/
@Target({ElementType.ANNOTATION_TYPE, ElementType.METHOD,
ElementType.FIELD // since 2.9
})
@Retention(RetentionPolicy.RUNTIME)
@JacksonAnnotation
public @interface JsonValue
{
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.
/**
* 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.
*/
boolean value() default true;
}