Annotation Interface Advice.FieldValue
- Enclosing class:
Advice
Indicates that the annotated parameter should be mapped to a field in the scope of the instrumented type.
Setting value()
is optional. If the value is not set, the field value attempts to bind a setter's
or getter's field if the intercepted method is an accessor method. Otherwise, the binding renders the target method
to be an illegal candidate for binding.
Important: Parameters with this option must not be used when from a constructor in combination with
Advice.OnMethodEnter
and a non-static field where the this
reference is not available.
Note: As the mapping is virtual, Byte Buddy might be required to reserve more space on the operand stack than the
optimal value when accessing this parameter. This does not normally matter as the additional space requirement is minimal.
However, if the runtime performance of class creation is secondary, one can require ASM to recompute the optimal frames by
setting ClassWriter.COMPUTE_MAXS
. This is however only relevant when writing to a non-static field.
Important: Don't confuse this annotation with FieldValue
or
MemberSubstitution.FieldValue
. This annotation should
be used only in combination with Advice
.
- See Also:
-
Optional Element Summary
Optional ElementsModifier and TypeOptional ElementDescriptionClass
<?> Returns the type that declares the field that should be mapped to the annotated parameter.boolean
Indicates if it is possible to write to this parameter.The typing that should be applied when assigning the field value.Returns the name of the field.
-
Element Details
-
value
String valueReturns the name of the field.- Returns:
- The name of the field.
- Default:
""
-
declaringType
Class<?> declaringTypeReturns the type that declares the field that should be mapped to the annotated parameter. If this property is set tovoid
, the field is looked up implicitly within the instrumented class's class hierarchy. The value can also be set toTargetType
in order to look up the type on the instrumented type.- Returns:
- The type that declares the field,
void
if this type should be determined implicitly orTargetType
for the instrumented type.
- Default:
void.class
-
readOnly
boolean readOnlyIndicates if it is possible to write to this parameter. If this property is set to
false
, the annotated type must be equal to the type declaring the instrumented method if the typing is not also set toAssigner.Typing.DYNAMIC
. If this property is set totrue
, the annotated parameter can be any super type of the instrumented method's declaring type.Important: This property must be set to
true
if the advice method is not inlined.- Returns:
true
if this parameter is read-only.
- Default:
true
-
typing
Assigner.Typing typingThe typing that should be applied when assigning the field value.- Returns:
- The typing to apply upon assignment.
- Default:
STATIC
-