Update:
Some 10 years later perhaps the best way to test a private method, or any inaccessible member, is via @Jailbreak
from the Manifold framework.
@Jailbreak Foo foo = new Foo();
// Direct, *type-safe* access to *all* foo's members
foo.privateMethod(x, y, z);
foo.privateField = value;
This way your code remains type-safe and readable. No design compromises, no overexposing methods and fields for the sake of tests.
If you have somewhat of a legacy Java application, and you're not allowed to change the visibility of your methods, the best way to test private methods is to use reflection.
Internally we're using helpers to get/set private
and private static
variables as well as invoke private
and private static
methods. The following patterns will let you do pretty much anything related to the private methods and fields. Of course, you can't change private static final
variables through reflection.
Method method = TargetClass.getDeclaredMethod(methodName, argClasses);
method.setAccessible(true);
return method.invoke(targetObject, argObjects);
And for fields:
Field field = TargetClass.getDeclaredField(fieldName);
field.setAccessible(true);
field.set(object, value);
Notes:
1. TargetClass.getDeclaredMethod(methodName, argClasses)
lets you look into private
methods. The same thing applies for
getDeclaredField
.
2. The setAccessible(true)
is required to play around with privates.
Coding from the hip, it would be something like:
java.lang.reflect.Method method;
try {
method = obj.getClass().getMethod(methodName, param1.class, param2.class, ..);
} catch (SecurityException e) { ... }
catch (NoSuchMethodException e) { ... }
The parameters identify the very specific method you need (if there are several overloaded available, if the method has no arguments, only give methodName
).
Then you invoke that method by calling
try {
method.invoke(obj, arg1, arg2,...);
} catch (IllegalArgumentException e) { ... }
catch (IllegalAccessException e) { ... }
catch (InvocationTargetException e) { ... }
Again, leave out the arguments in .invoke
, if you don't have any. But yeah. Read about Java Reflection
Best Answer
Keep a reference to the timer somewhere, and use:
to stop whatever it's doing. You could put this code inside the task you're performing with a
static int
to count the number of times you've gone around, e.g.