DevFaqLookupGenerics

How do I use Java Generics with Lookup?

As of NetBeans 6, a number of convenience methods have been added to lookup, and support for Java generics has been added to Lookup. The following are differences (assume that lkp is a Lookup):

NB 5.x Code	NB 6 Code
DataObject dob = (DataObject) lkp.lookup(DataObject.class)	DataObject dob = lkp.lookup(DataObject.class)
Lookup.Result r = lkp.lookup(new Lookup.Template(X.class))	Lookup.Result<? extends X> r = lkp.lookupResult(X.class)
Collection c = r.allInstances()	Collection<? extends X> c = r.allInstances()
Lookup.Template t = new Lookup.Template(X.class); Lookup.Result r = lkp.lookup(t); Collection c = r.allInstances();	Collection<? extends X> c = lkp.lookupAll(X.class);
Lookup.Template t = new Lookup.Template(X.class); Lookup.Result r = lkp.lookup(t); Collection c = r.allInstances(); for (Iterator it=c.iterator(); it.hasNext();) {   X x = (X) it.next();   //do something with x }	for (X x : lkp.lookupAll(X.class)) {   //do something with x }

Generics work well with JDK-5-style for-loops:

for (SomeService s : Lookup.getDefault().lookupAll(SomeService.class)) {
    // ...
}