Package com.google.common.reflect

Interface TypeToInstanceMap<B>

Type Parameters:

B - the common supertype that all entries must share; often this is simply Object

All Superinterfaces:

Map<TypeToken<? extends B>,B>

All Known Implementing Classes:

ImmutableTypeToInstanceMap, MutableTypeToInstanceMap

@DoNotMock("Use ImmutableTypeToInstanceMap or MutableTypeToInstanceMap")
public interface TypeToInstanceMap<B>
extends Map<TypeToken<? extends B>,B>

A map, each entry of which maps a TypeToken to an instance of that type. In addition to implementing Map, the additional type-safe operations putInstance(java.lang.Class<T>, T) and getInstance(java.lang.Class<T>) are available.

Generally, implementations don't support Map.put(K, V) and Map.putAll(java.util.Map<? extends K, ? extends V>) because there is no way to check an object at runtime to be an instance of a TypeToken. Instead, caller should use the type safe putInstance(java.lang.Class<T>, T).

Also, if caller suppresses unchecked warnings and passes in an Iterable<String> for type Iterable<Integer>, the map won't be able to detect and throw type error.

Like any other Map<Class, Object>, this map may contain entries for primitive types, and a primitive type and its corresponding wrapper type may map to different values.

This class's support for null requires some explanation. For details, see ClassToInstanceMap. Its explanation applies equally well to TypeToInstanceMap.

Since:

13.0

Author:

Ben Yu

Nested Class Summary

Nested classes/interfaces inherited from interface java.util.Map

Map.Entry<K,V>

Method Summary

Modifier and Type	Method	Description
<T extends B> T	getInstance(TypeToken<T> type)	Returns the value the specified type is mapped to, or null if no entry for this type is present.
<T extends B> T	getInstance(Class<T> type)	Returns the value the specified class is mapped to, or null if no entry for this class is present.
<T extends B> T	putInstance(TypeToken<T> type, T value)	Maps the specified type to the specified value.
<T extends B> T	putInstance(Class<T> type, T value)	Maps the specified class to the specified value.

Methods inherited from interface java.util.Map

clear, compute, computeIfAbsent, computeIfPresent, containsKey, containsValue, entrySet, equals, forEach, get, getOrDefault, hashCode, isEmpty, keySet, merge, put, putAll, putIfAbsent, remove, remove, replace, replace, replaceAll, size, values

Method Detail

getInstance

@CheckForNull
<T extends B> T getInstance(Class<T> type)

Returns the value the specified class is mapped to, or null if no entry for this class is present. This will only return a value that was bound to this specific class, not a value that may have been bound to a subtype.

getInstance(Foo.class) is equivalent to getInstance(TypeToken.of(Foo.class)).

getInstance

@CheckForNull
<T extends B> T getInstance(TypeToken<T> type)

Returns the value the specified type is mapped to, or null if no entry for this type is present. This will only return a value that was bound to this specific type, not a value that may have been bound to a subtype.

putInstance

@CanIgnoreReturnValue
@CheckForNull
<T extends B> T putInstance(Class<T> type,
                            T value)

Maps the specified class to the specified value. Does not associate this value with any of the class's supertypes.

putInstance(Foo.class, foo) is equivalent to putInstance(TypeToken.of(Foo.class), foo).

Returns:

the value previously associated with this class (possibly null), or null if there was no previous entry.

putInstance

@CanIgnoreReturnValue
@CheckForNull
<T extends B> T putInstance(TypeToken<T> type,
                            T value)

Maps the specified type to the specified value. Does not associate this value with any of the type's supertypes.

Returns:

the value previously associated with this type (possibly null), or null if there was no previous entry.