com.google.inject.multibindings

Interface MapBinderBinding<T>

Type Parameters:

T - The fully qualified type of the map, including Map. For example: MapBinderBinding<Map<String, Snack>>

public interface MapBinderBinding<T>

A binding for a MapBinder.

Although MapBinders may be injected through a variety of generic types (Map<K, V>, Map <K, Provider<V>>, Map<K, Set<V>>, Map>, and even Set<Map.Entry<K, Provider<V>>), a MapBinderBinding exists only on the Binding associated with the Map<K, V> key. Other bindings can be validated to be derived from this MapBinderBinding using containsElement(Element).

Since:

3.0

Method Summary

Modifier and Type	Method and Description
boolean	containsElement(Element element) Returns true if this MapBinder contains the given Element in order to build the map or uses the given Element in order to support building and injecting the map.
java.util.List<java.util.Map.Entry<?,Binding<?>>>	getEntries() Returns all entries in the Map.
java.util.List<java.util.Map.Entry<?,Binding<?>>>	getEntries(java.lang.Iterable<? extends Element> elements) Similar to getEntries(), but can be used on a MapBinderBinding retrieved from Elements.getElements(com.google.inject.Module...).
TypeLiteral<?>	getKeyTypeLiteral() Returns the TypeLiteral describing the keys of the map.
Key<T>	getMapKey() Returns the Key for the map.
TypeLiteral<?>	getValueTypeLiteral() Returns the TypeLiteral describing the values of the map.
boolean	permitsDuplicates() Returns true if the MapBinder permits duplicates.

Method Detail

getMapKey

Key<T> getMapKey()

Returns the Key for the map.

getKeyTypeLiteral

TypeLiteral<?> getKeyTypeLiteral()

Returns the TypeLiteral describing the keys of the map.

The TypeLiteral will always match the type Map's generic type. For example, if getMapKey returns a key of Map<String, Snack>, then this will always return a TypeLiteral<String>.

getValueTypeLiteral

TypeLiteral<?> getValueTypeLiteral()

Returns the TypeLiteral describing the values of the map.

The TypeLiteral will always match the type Map's generic type. For example, if getMapKey returns a key of Map<String, Snack>, then this will always return a TypeLiteral<Snack>.

getEntries

java.util.List<java.util.Map.Entry<?,Binding<?>>> getEntries()

Returns all entries in the Map. The returned list of Map.Entries contains the key and a binding to the value. Duplicate keys or values will exist as separate Map.Entries in the returned list. This is only supported on bindings returned from an injector. This will throw UnsupportedOperationException if it is called on an element retrieved from Elements.getElements(com.google.inject.Module...).

The elements will always match the type Map's generic type. For example, if getMapKey returns a key of Map<String, Snack>, then this will always return a list of type List<Map.Entry<String, Binding<Snack>>>.

getEntries

java.util.List<java.util.Map.Entry<?,Binding<?>>> getEntries(java.lang.Iterable<? extends Element> elements)

Similar to getEntries(), but can be used on a MapBinderBinding retrieved from Elements.getElements(com.google.inject.Module...).

One way to use this is to pass in the results of Elements.getElements(com.google.inject.Module...) as the elements parameter.

This differs from getEntries() in that it will return duplicates if they are present in the elements passed in. This does not run the normal Guice de-duplication that getEntries() does.

Throws:

java.lang.IllegalArgumentException - if the provided elements contain partial map entries. If the elements come from Elements.getElements(com.google.inject.Module...) on a module with a MapBinder, there will be a 1:1 relationship and no exception will be thrown.

Since:

4.2

permitsDuplicates

boolean permitsDuplicates()

Returns true if the MapBinder permits duplicates. This is only supported on bindings returned from an injector. This will throw UnsupportedOperationException if it is called on a MapBinderBinding retrieved from Elements.getElements(com.google.inject.Module...).

containsElement

boolean containsElement(Element element)

Returns true if this MapBinder contains the given Element in order to build the map or uses the given Element in order to support building and injecting the map. This will work for MapBinderBindings retrieved from an injector and Elements.getElements(com.google.inject.Module...). Usually this is only necessary if you are working with elements retrieved from modules (without an Injector), otherwise getEntries() and permitsDuplicates() are better options.

If you need to introspect the details of the map, such as the keys, values or if it permits duplicates, it is necessary to pass the elements through an Injector and use getEntries() and permitsDuplicates().