Java null object reference
.jnull returns a null reference of a specified class
type. The resulting object is of the class jobjRef.
is.jnull is an extension of is.null that also returns
TRUE if the supplied object is a null Java reference.
.jnull(class = "java/lang/Object") is.jnull(x)
class |
fully qualified target class name in JNI notation
(e.g. |
x |
object to check |
Example: given the following method definitions of the class A:
opublic static void run(String a);
opublic static void run(Double n);
Calling .jcall("A",,"run",NULL) is ambiguous, because it is
unclear which method is to be used. Therefore rJava requires class
information with each argument to .jcall. If we wanted
to run the String-version, we could use
.jcall("A",,"run",.jnull("java/lang/String")).
is.jnull is a test that should be used to determine whether a
given Java reference is a null reference.
.jnull returns a Java object reference (jobjRef) of a
null object having the specified object class.
is.jnull returns TRUE if is.null(x) is
TRUE or if x is a Java null reference.
## Not run:
.jcall("java/lang/System","I","identityHashCode",.jnull())
## End(Not run)Please choose more modern alternatives, such as Google Chrome or Mozilla Firefox.