jcastToArray.Rd.jcastToArray takes a Java object reference of any kind and
returns Java array reference if the given object is a reference to an
array.
.jcastToArray(obj, signature=NULL, class="", quiet=FALSE)Java object reference to cast or a scalar vector
array signature in JNI notation (e.g. "[I" for
an array of integers). If set to NULL (the default),
the signature is automatically determined from the object's class.
force the result to pose as a particular Java
class. This has the same effect as using .jcast on the
result and is provided for convenience only.
if set to TRUE, no failures are reported and the
original object is returned unmodified.
Returns a Java array reference (jarrayRef) on success. If
quiet is TRUE then the result can also be the original
object in the case of failure.
Sometimes a result of a method is by definition of the class
java.lang.Object, but the actual referenced object may be an
array. In that case the method returns a Java object reference instead
of an array reference. In order to obtain an array reference, it is
necessary to cast such an object to an array reference - this is done
using the above .jcastToArray function.
The input is an object reference that points to an array. Usually the
signature should be left at NULL such that it is determined
from the object's class. This is also a check, because if the object's
class is not an array, then the functions fails either with an error
(when quiet=FALSE) or by returning the original object (when
quiet=TRUE). If the signature is set to anything else, it is
not verified and the array reference is always created, even if it may
be invalid and unusable.
For convenience .jcastToArray also accepts non-references in
which case it simply calls .jarray, ignoring all other
parameters.
if (FALSE) { # \dontrun{
a <- .jarray(1:10)
print(a)
# let's create an array containing the array
aa <- .jarray(list(a))
print(aa)
ba <- .jevalArray(aa)[[1]]
# it is NOT the inverse, because .jarray works on a list of objects
print(ba)
# so we need to cast the object into an array
b <- .jcastToArray(ba)
# only now a and b are the same array reference
print(b)
# for convenience .jcastToArray behaves like .jarray for non-references
print(.jcastToArray(1:10/2))
} # }