Java Reference
In-Depth Information
Unlike
Eval
,the
GroovyShell
classdoesnotcontainonlystaticmethods.Itneedstobe
instantiated before invoking its
evaluate
method. As a simple example, consider adding
the following test to the previous set of test cases:
@Test
public void testEvaluateString() {
GroovyShell shell = new GroovyShell();
Object result = shell.evaluate("3+4");
assertEquals(7, result);
}
The
evaluate
method is heavily overloaded. The version I'm using here takes a string
representing the script to be evaluated. Other overloads take a
java.io.File
or a
java.io.Reader
instance, with various additional arguments. There are overloads that
take a
java.io.InputStream
as well, but they're deprecated due to possible encod-
ing issues.
So far, using the
GroovyShell
looks a lot like using the
ScriptEngine
class, though
you can instantiate it directly in this case. To deal with input and output variables, however,
the
GroovyShell
uses the
groovy.lang.Binding
class to provide a map of input
and output variables.
The next listing shows the
Binding
and
GroovyShell
classes in action. It's another
test to add to the growing JUnit 4 test case.
