java - Dagger2: Using factory methods in place of public constructors -

i trying use public factory methods in place of public constructors dagger2. think missing connection in using dagger2.

when use public constructors, example interfaces / classes follows:

interface interfacea {     void foo(); }  class implements interfacea {      @inject public a() {}      @override     public void foo() {         system.out.println("foo");     } }  interface interfaceb {     void bar(); }  class b implements interfaceb {      private final interfacea depa;      @inject public b(interfacea depinstance) {         depa = depinstance;     }      @override     public void bar() {         system.out.println("bar");         depa.foo();     } }  @module class mymodule {      @provides interfacea providea(final provider<a> provider) {         return a.create(provider);     }      @provides interfaceb provideb(b binstance) {         return binstance;     } }  @component(modules=mymodule.class) interface mycomponent {     interfacea provideinterfacea();     interfaceb provideinterfaceb(); } 

usage above:

public class test {      public static void main(string[] args) {         mycomponent comp = daggermycomponent.create();         interfacea = comp.provideinterfacea();         a.foo();         interfaceb b = comp.provideinterfaceb();         b.bar();     } } 

now, if rewrite classes , b follows:

class implements interfacea {      public static create() {         return new a();     }      private a() {}      @override     public void foo() {         system.out.println("foo");     } }  class b implements interfaceb {      public static b create(interfacea depa) {         return new b(depa);     }      private final interfacea depa;      private b(interfacea depinstance) {         depa = depinstance;     }      @override     public void bar() {         system.out.println("bar");         depa.foo();     } } 

i able re-write mymodule class as:

@module class mymodule {      @provides interfacea providea() {         return a.create();     }      @provides interfaceb provideb() {         return b.create(providea());     } } 

but not use of dagger2 framework. looks not writing classes use inject , provides annotations correctly. missing?

you're pretty close, you're making minor mistakes though. should provide instance provider method using method parameter, otherwise you'd create multiple instances in case of scoped provider. , can use void inject(something something); if want.

@module class mymodule {      @provides interfacea providea() {         return a.create();     }      @provides interfaceb provideb(interface interfacea) {         return b.create(interfacea);     } }   @component(modules=mymodule.class) interface mycomponent {     interfacea provideinterfacea();     interfaceb provideinterfaceb();      void inject(test test); }  public class test {     @inject     interfacea a;      @inject     interfaceb b;        public static void main(string[] args) {         mycomponent comp = daggermycomponent.create();         comp.inject(this);         a.foo();         b.bar();     } }