com4j

Annotation Type UseDefaultValues

@Retention(value=RUNTIME)
@Target(value=METHOD)
public @interface UseDefaultValues

Author:

Michael Schnell (scm, (C) 2008, Michael-Schnell@gmx.de)

Required Element Summary

Required Elements

Modifier and Type	Required Element and Description
Class<?>[]	javaType
String[]	literal
NativeType[]	nativeType
int[]	optParamIndex
int[]	paramIndexMapping Returns an array of indices, that maps the parameter of the java interface to the parameter index of the COM interface Assume we have an COM interface with an function like
Variant.Type[]	variantType A list of Variant.Types used to generate the default parameters.

Element Detail

paramIndexMapping

public abstract int[] paramIndexMapping

Returns an array of indices, that maps the parameter of the java interface to the parameter index of the COM interface
Assume we have an COM interface with an function like

 [helpstring("Test function")]
 HRESULT TestFunction([in] VARIANT notOptional, [in, optional, defaultvalue("forty-two")] VARIANT opt1,
                      [in, defaultvalue(42)] VARIANT opt2, [in, lcid] long localeID, [out, retval] VARIANT *result);
 

Then we can generate three Java interface methods:

 Variant testFunction(Variant notOptional, Variant opt1, Variant opt2, int localeID);

 Variant testFunction(Variant notOptional, Variant opt1, int localeID);

 Variant testFunction(Variant notOptional, int localeID);
 

The first function would not need a UseDefaultValues annotation at all. The second function needs an annotation with a parameter mapping [0, 1, 3] and the third function needs the mapping [0, 3]
The mapping wouldn't be necessary, if we consider that there is at most one [lcid] parameter and that this parameter always needs to be at the end of the optional parameters. But consider the case, where we have an list of optional parameters with default values and Com4j is not able to handle an optional parameter in the middle of list. Using parameter index mapping makes it possible to generate Java interface methods anyway.

Returns:

A list of indices, mapping the java parameter to the index of the COM parameter

optParamIndex

public abstract int[] optParamIndex

Returns:

A list of the indices, naming the position of the optional parameters in the COM function

javaType

public abstract Class<?>[] javaType

Returns:

A list of Java Classes used to represent the optional parameters on the Java side.

nativeType

public abstract NativeType[] nativeType

Returns:

A list of NativeTypes used to generate the default parameters

variantType

public abstract Variant.Type[] variantType

A list of Variant.Types used to generate the default parameters. The entry in this list is only needed in the case that the corresponding NativeType is of type NativeType.VARIANT

Returns:

A list of Variant.Types used to generate the default parameters.

literal

public abstract String[] literal

Returns:

A List of Strings representing the default parameter.