java - Guice Binding for List of generic Objects -

what binding statement need tell guice want onefoo , twofoo injected bar list of foo? setup here chain of responsibility. right have 2 implementations, bar doesn't need know that.

@inject bar(list<foo> foos) {...} ... class onefoo implements foo {     @inject     onefoo(...) {...} ... class twofoo implements foo {     @inject     twofoo(...) {...} 

but i'm struggling using types, typeliteral, etc configure binding 2 foo implementations given bar.

if know @ compile time bindings, can use @provides method in module:

class mymodule extends abstractmodule() {     @override     protected void configure() {         // ...     }      @provides     @inject     public list<foo> foos(onefoo one, twofoo two) {         return arrays.aslist(one, two);     } } 

you can expand foos's argument list needed. similar, more verbose approach, use provider:

protected void configure() {     bind(new typeliteral<list<foo>>() {})        .toprovider(foolistprovider.class); }  static class foolistprovider implements provider<list<foo>> {     @inject     provider<onefoo> one;     @inject     provider<twofoo> two;      public list<foo> get() {         return arrays.aslist(one.get(), two.get());     } } 

in case want singleton list in onefoo , twofoo injected, can add @singleton annotation. recommend making list immutable @ point:

@singleton @provides @inject public list<foo> foos(onefoo one, twofoo two) {     return collections.unmodifiablelist(arrays.aslist(one, two)); } 

if on other hand, want singleton list onefoo , twofoo not injected, can use typeliteral:

@override protected void configure() {     bind(new typeliteral<list<foo>>() {})         .toinstance(arrays.aslist(new onefoo(), new twofoo())); } 

in case too, again, i'd suggest making list unmodifiable.