net.bytebuddy.asm

Annotation Type Advice.FieldValue

@Documented
 @Retention(value=RUNTIME)
 @Target(value=PARAMETER)
public static @interface Advice.FieldValue

Indicates that the annotated parameter should be mapped to a field in the scope of the instrumented method.

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.

See Also:

Advice, Advice.OnMethodEnter, Advice.OnMethodExit

Required Element Summary

Required Elements

Modifier and Type	Required Element and Description
String	value Returns the name of the field.

Optional Element Summary

Optional Elements

Modifier and Type	Optional Element and Description
Class<?>	declaringType Returns the type that declares the field that should be mapped to the annotated parameter.
boolean	readOnly Indicates if it is possible to write to this parameter.
Assigner.Typing	typing The typing that should be applied when assigning the field value.

Element Detail

value

public abstract String value

Returns the name of the field.

Returns:

The name of the field.

declaringType

public abstract Class<?> declaringType

Returns the type that declares the field that should be mapped to the annotated parameter. If this property is set to void, the field is looked up implicitly within the instrumented class's class hierarchy. The value can also be set to TargetType 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 or TargetType for the instrumented type.

Default:

void.class

readOnly

public abstract boolean readOnly

Indicates 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 to Assigner.Typing#DYNAMIC. If this property is set to true, 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

public abstract Assigner.Typing typing

The typing that should be applied when assigning the field value.

Returns:

The typing to apply upon assignment.

Default:

net.bytebuddy.implementation.bytecode.assign.Assigner.Typing.STATIC