net.lenni0451.classtransform.annotations.injection

Annotation Type CModifyExpressionValue

@Retention(value=CLASS)
 @Target(value=METHOD)
public @interface CModifyExpressionValue

Modify the value of an expression (method call/field access/new object creation).

When modifying the value (return value) of a method call, the target method must return a value and not be void.
Field values can be modified with field gets (GETFIELD/GETSTATIC) and field sets (PUTFIELD/PUTSTATIC).
New object creations can be modified with the NEW target.

The transformer method must have the modified value type as the only parameter and return type.
If the transformer target method is static, the transformer method must be static as well.

Modify the return value of a method call:

 @CModifyExpressionValue(method = "print", target = @CTarget(value = "INVOKE", target = "Ljava/lang/Object;toString()Ljava/lang/String;"))
 public String modifyValue(String value) {
     return value.toUpperCase();
 }
 

Modify the value of a field access:

 @CModifyExpressionValue(method = "print", target = @CTarget(value = "GETFIELD", target = "Ljava/lang/Integer;MAX_VALUE:I"))
 public int modifyValue(int value) {
     return Integer.MIN_VALUE;
 }
 

Modify the value of a new object creation:

 @CModifyExpressionValue(method = "print", target = @CTarget(value = "NEW", target = "java/lang/String"))
 public String modifyValue(String value) {
     return value.toUpperCase();
 }
 

See Also:

CTarget, CSlice, GitHub Wiki

Required Element Summary

Required Elements

Modifier and Type	Required Element and Description
java.lang.String[]	method The method name and descriptor to inject into. This supports multiple targets and wildcards. e.g.
CTarget	target The target expression to modify the value of.

Optional Element Summary

Optional Elements

Modifier and Type	Optional Element and Description
CSlice	slice The slice to narrow down the search for the target.

Element Detail

method

public abstract java.lang.String[] method

The method name and descriptor to inject into.
This supports multiple targets and wildcards.
e.g. print(Ljava/lang/String;)V or print*

Returns:

The method name and descriptor

target

public abstract CTarget target

The target expression to modify the value of.

Returns:

The target

slice

public abstract CSlice slice

The slice to narrow down the search for the target.

Returns:

The slice

Default:

@net.lenni0451.classtransform.annotations.CSlice