It's hard to tell exactly what you are meaning, but I think what you are
asking is the IState class is generic to IParser, so both excel handler
and word handler both use the same IState implementation but with two
different parsers. In this case you're not able to inject the IState
into the ContentHandler because Guice doesn't know that the IState for
ExcelHandler needs ExcelParser.
I just had a very similar problem and it is the "robot legs" problem
mentioned in the FAQ (which you can find example online at the Guice
site). What I did is made two separate modules (in your case it would be
WordModule and ExcelModule). In each case there's only one way for
IState to be constructed so it works. You need to make the modules
private so that their IState bindings don't conflict. Then you would
expose() only the content handler in each module. When you make the
injector you pass both modules. You can pull out the specific content
handler via the annotation.
Jason
On 8/22/2010 8:07 AM, gregory wrote:
Newbie Alert .
My problem is how to use binding annotation in case when chain of
dependency is not defined with the annotation all the way.
Binding annotations *Excel* and *Word* are used to bind
*ContentHandler* and *IParser* interfaces but not *IState* interface
(see *MyModule*). The dependency looks like this:
ContentHandler -> IState -> IParser
public class ExcelHandler implements ContentHandler {
@Inject
public ExcelHandler(@Excel IParser parser) {
IState = new State(parser);
}
}
public class MyModule extends AbsractModule {
protected void configure() {
bind(ContentHandler.class).annotatedWith(Excel.class).
to(ExcelContentHandler.class);
bind(ContentHandler.class).annotatedWith(Word.class).
to(WordContentHandler.class);
bind(IParser.class).annotatedWith(Excel.class).
to(ExcelParser.class);
bind(IParser.class).annotatedWith(Word.class).
to(WordParser.class);
bind(IState.class).to(State.class);
}
}
I obtain initial instance with injector:
ContentHandler handler =
injector.getInstance(Key.get(ContentHandler.class, Excel.class));
How to use guice to replace explicit constructor?
IState = new State(parser);
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