On Jun 26, 2012, at 7:49 AM, Paulo Pires wrote: > Hi all, > > This is a guidance request from someone who's interested in learning Guice. > > I'm developing a Java SE application with some windows (SWT) that interacts > with the network (Netty.IO) and when some conditions are true writes to a > database by means of DAOs. Right now, my code is somewhat tightly-coupled, so > trying to put Guice to work is proving to be a true PITA. > > My main issue is how to get instances from the injector in classes that are 3 > or 4 layers deep (not injected). > > I'd really appreciate if you could provide your approach on how you'd do this.
Can you give a simplified source code example? I'm not sure what you mean. If a class isn't injected by the Injector, then you can't get it, unless the injected classes expose getters that let you obtain it through these means. Often, it's very hard to move tightly coupled code into a dependency-injection pattern, because it's really a substantial design change. often, I find it easiest to start in one of two ways- at the top… take the big object and put it in the injector (the one that creates all its dependencies), and start pulling out those dependencies and injecting them in turn. The other approach is to start with singletons, and re-tool them so that their getInstance() methods have access to a global singleton injector, and start migrating code that way. There are lots of migration patterns, and which one is optimal is really quite dependent on your situation. But unless the Injector knows about the class (it's bound), then you can't get it from the injector, you can only get it from a class that the Injector knows about, which exposes it through accessors. Christian. -- You received this message because you are subscribed to the Google Groups "google-guice" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/google-guice?hl=en.
