Multibind map object (and possible bug?)

[Donald Blodgett]

Is there a way to multibind a java.util.Map?

Also not sure if I understand multibind completely or if this is a bug. I have the following code. The expected Integers are [1, 3], but for the testMultibindList and testMultibindSet ints equals [1, 2, 3] where in TestMultibindArray ints equals [1, 3] as expected.

public class DiTest {

   @Test

   public void testMultibindList() {

      Injector injector = Bootstrap.injector(TestBundle.class);

      Dependency<List> dependency = Dependency.dependency(Type.raw(List.class).parametized(Integer.class));

      List ints = injector.resolve(dependency.named("list_1"));

      

      Integer[] a = (Integer[]) ints.toArray(new Integer[ints.size()]);

      Arrays.sort(a);

      ints = Arrays.asList(a);

      

      List exp = new ArrayList();

      exp.add(1);

      exp.add(3);

      

      Assert.assertEquals(exp, ints);

   }

   

   @Test

   public void testMultibindSet() {

      Injector injector = Bootstrap.injector(TestBundle.class);

      Dependency<Set> dependency = Dependency.dependency(Type.raw(Set.class).parametized(Integer.class));

      Set ints = injector.resolve(dependency.named("list_1"));

      

      Set exp = new HashSet();

      exp.add(1);

      exp.add(3);

      

      Assert.assertEquals(exp, ints);

   }

   

   @Test

   public void testMultibindArray() {

      Injector injector = Bootstrap.injector(TestBundle.class);

      Dependency<Integer[]> dependency = Dependency.dependency(Type.raw(Integer[].class));

      Integer[] ints = injector.resolve(dependency.named("list_1"));

      

      Arrays.sort(ints);

      

      Integer[] exp = new Integer[] {1, 3};

      

      Assert.assertArrayEquals(exp, ints);

   }

}

public class TestBundle extends BootstrapperBundle {

   @Override

   protected void bootstrap() {

      install(TestModule.class);

      install(TestModule2.class);

      install(BuildinBundle.LIST);

      install(BuildinBundle.SET);

   }

}

public class TestModule extends BinderModule {

   @Override

   protected void declare() {

      multibind(Name.named("list_1"), Integer.class).to(1);

      multibind(Name.named("list_2"), Integer.class).to(2);

   }

}

public class TestModule2 extends BinderModule {

   @Override

   protected void declare() {

      multibind(Name.named("list_1"), Integer.class).to(3);

   }

}

[jan]

Hi,

On Sunday, 14 April 2013 21:38:10 UTC+2, Donald Blodgett wrote:

Is there a way to multibind a java.util.Map?

I assume you mean Map as result that is injected.

It is possible by adding a bridge like you have done for Set or List. Since I don't see a what value would be used as key there is no such bridge build in. You could do something like this.

class ArrayToMapBridgeSupplier extends ArrayBridgeSupplier<Map<?>> {

	@Override
	<E> Map<E> bridge( E[] elements ) {
		Map<E> res = new HashMap<E>();
		// fill map from elements
		return res;
	}
}

per( DEPENDENCY_TYPE ).starbind( Map.class ).to( new ArrayToMapBridgeSupplier() );

 

 

Also not sure if I understand multibind completely or if this is a bug. I have the following code. The expected Integers are [1, 3], but for the testMultibindList and testMultibindSet ints equals [1, 2, 3] where in TestMultibindArray ints equals [1, 3] as expected.

You used same instance name twice. That is not how it was meant to be used. I haven't thought about that possibility to use multibinds that way. E.g. to have different List instances. Right now it works on type level. Still all binds are kept and added to later lists or sets since those just filter. But it either should result in the list you expected or throw an exception since same instance has been bound twice.

Do you have a concrete use case or was it just a test ?

Jan

P.S. I noticed that there is no tool to add code blocks here. I assume this needs to be configured. 

[jan]

P.S. I noticed that there is no tool to add code blocks here. I assume this needs to be configured. 

// Has been enabled now

 

[jan]

On Sunday, 14 April 2013 21:38:10 UTC+2, Donald Blodgett wrote:

Also not sure if I understand multibind completely or if this is a bug. I have the following code. The expected Integers are [1, 3], but for the testMultibindList and testMultibindSet ints equals [1, 2, 3] where in TestMultibindArray ints equals [1, 3] as expected.

I created a test for this. 

I misunderstood the case. I assume that the multibind works as you expect. E.g. binding to 2 different named instances will work like adding elements. This works as long as working with the arrays directly. 

But what currently does not work is asking for named Lists or Sets. I am not 100% sure that it should work like that but I think it should be transparently work equally to the array. 

The name is lost during the link from List to array. I have to make sure that forwarding this does not cause problems in other cases, apart from that it is easy to change.

[jan]

Looks like we can call this a bug (in the List/Set bridge). I fixed it so now this test https://github.com/jbee/silk/blob/master/src/test/se/jbee/inject/bind/TestMultibindBinds.java works. 

You can take a look at the 3 commits https://github.com/jbee/silk/commits/ made on 15. April. to see the changes. It would work to apply them to 0.5 youself by just installing/binding a fixed version of the List/Set bridges.