org.graalvm.nativebridge

Annotation Type Out

@Retention(value=CLASS)
 @Target(value=PARAMETER)
public @interface Out

Configures an array parameter as an out-parameter. For an out-parameter, the array value is copied over the boundary from a called method. It may be combined with In for in-out parameters. Example showing the configuration for OutputStream.write(byte[], int, int).

 @Override
 public abstract int read(@Out(arrayOffsetParameter = "off", arrayLengthParameter = "len", trimToResult = true) byte[] b, int off, int len);
 

Optional Element Summary

Optional Elements

Modifier and Type	Optional Element and Description
String	arrayLengthParameter Limits copying only to many of the elements given by the arrayLengthParameter parameter.
String	arrayOffsetParameter Copy only a part of the array starting at offset given by the arrayOffsetParameter method parameter.
boolean	trimToResult Limits copying only to method result number of elements.

Element Detail

arrayOffsetParameter

public abstract String arrayOffsetParameter

Copy only a part of the array starting at offset given by the arrayOffsetParameter method parameter. By default, the whole array is copied. The arrayOffsetParameter can be used to improve the performance and copy only a part of the array over the boundary.

Default:

""

arrayLengthParameter

public abstract String arrayLengthParameter

Limits copying only to many of the elements given by the arrayLengthParameter parameter. By default, the whole array is copied. The arrayLengthParameter can be used to improve the performance and copy only a part of the array over the boundary.

Default:

""

trimToResult

public abstract boolean trimToResult

Limits copying only to method result number of elements. It can be used to further limit the number of copied elements in addition to Out.arrayLengthParameter(). When used, it's still good to specify Out.arrayLengthParameter() as an upper bound to limit allocated array size.

Default:

false