Key (guice 4.2.3)

java.lang.Object
- com.google.inject.Key<T>

```
public class Key<T>
extends Object
```
Binding key consisting of an injection type and an optional annotation. Matches the type and annotation at a point of injection.
For example, Key.get(Service.class, Transactional.class) will match:
```
    @Inject
   public void setService( @Transactional Service service) {
     ...
   }
 
```
Key supports generic types via subclassing just like TypeLiteral.
Keys do not differentiate between primitive types (int, char, etc.) and their corresponding wrapper types (Integer, Character, etc.). Primitive types will be replaced with their wrapper types when keys are created.
Author:

crazybob@google.com (Bob Lee)

Constructor Summary

Constructors
Modifier	Constructor and Description
`protected`	`Key()` Constructs a new key.
`protected`	`Key(Annotation annotation)` Constructs a new key.
`protected`	`Key(Class<? extends Annotation> annotationType)` Constructs a new key.

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`boolean`	`equals(Object o)`
`static <T> Key<T>`	`get(Class<T> type)` Gets a key for an injection type.
`static <T> Key<T>`	`get(Class<T> type, Annotation annotation)` Gets a key for an injection type and an annotation.
`static <T> Key<T>`	`get(Class<T> type, Class<? extends Annotation> annotationType)` Gets a key for an injection type and an annotation type.
`static Key<?>`	`get(Type type)` Gets a key for an injection type.
`static Key<?>`	`get(Type type, Annotation annotation)` Gets a key for an injection type and an annotation.
`static Key<?>`	`get(Type type, Class<? extends Annotation> annotationType)` Gets a key for an injection type and an annotation type.
`static <T> Key<T>`	`get(TypeLiteral<T> typeLiteral)` Gets a key for an injection type.
`static <T> Key<T>`	`get(TypeLiteral<T> typeLiteral, Annotation annotation)` Gets a key for an injection type and an annotation.
`static <T> Key<T>`	`get(TypeLiteral<T> typeLiteral, Class<? extends Annotation> annotationType)` Gets a key for an injection type and an annotation type.
`Annotation`	`getAnnotation()` Gets the annotation instance if available.
`Class<? extends Annotation>`	`getAnnotationType()` Gets the annotation type.
`TypeLiteral<T>`	`getTypeLiteral()` Gets the key type.
`boolean`	`hasAttributes()` Returns true if this key has annotation attributes.
`int`	`hashCode()`
`<T> Key<T>`	`ofType(Class<T> type)` Returns a new key of the specified type with the same annotation as this key.
`Key<?>`	`ofType(Type type)` Returns a new key of the specified type with the same annotation as this key.
`<T> Key<T>`	`ofType(TypeLiteral<T> type)` Returns a new key of the specified type with the same annotation as this key.
`String`	`toString()`
`Key<T>`	`withoutAttributes()` Returns this key without annotation attributes, i.e.

Methods inherited from class java.lang.Object
clone, finalize, getClass, notify, notifyAll, wait, wait, wait

- Constructor Detail
  - Key
```
protected Key(Class<? extends Annotation> annotationType)
```
    Constructs a new key. Derives the type from this class's type parameter.
    Clients create an empty anonymous subclass. Doing so embeds the type parameter in the anonymous class's type hierarchy so we can reconstitute it at runtime despite erasure.
    Example usage for a binding of type Foo annotated with @Bar:
    new Key<Foo>(Bar.class) {}.
  - Key
```
protected Key(Annotation annotation)
```
    Constructs a new key. Derives the type from this class's type parameter.
    Clients create an empty anonymous subclass. Doing so embeds the type parameter in the anonymous class's type hierarchy so we can reconstitute it at runtime despite erasure.
    Example usage for a binding of type Foo annotated with @Bar:
    new Key<Foo>(new Bar()) {}.
  - Key
```
protected Key()
```
    Constructs a new key. Derives the type from this class's type parameter.
    Clients create an empty anonymous subclass. Doing so embeds the type parameter in the anonymous class's type hierarchy so we can reconstitute it at runtime despite erasure.
    Example usage for a binding of type Foo:
    new Key<Foo>() {}.
- Method Detail
  - getTypeLiteral
```
public final TypeLiteral<T> getTypeLiteral()
```
    Gets the key type.
  - getAnnotationType
```
public final Class<? extends Annotation> getAnnotationType()
```
    Gets the annotation type. Will be null if this key lacks an annotation.
  - getAnnotation
```
public final Annotation getAnnotation()
```
    Gets the annotation instance if available. Will be null if this key lacks an annotation or the key was constructed with a Class<Annotation>.
    Warning: this can return null even if this key is annotated. To check whether a Key has an annotation use hasAnnotationType() instead.
  - equals
```
public final boolean equals(Object o)
```
    Overrides:
    
    equals in class Object
  - hashCode
```
public final int hashCode()
```
    Overrides:
    
    hashCode in class Object
  - toString
```
public final String toString()
```
    Overrides:
    
    toString in class Object
  - get
```
public static <T> Key<T> get(Class<T> type)
```
    Gets a key for an injection type.
  - get
```
public static <T> Key<T> get(Class<T> type,
                             Class<? extends Annotation> annotationType)
```
    Gets a key for an injection type and an annotation type.
  - get
```
public static <T> Key<T> get(Class<T> type,
                             Annotation annotation)
```
    Gets a key for an injection type and an annotation.
  - get
```
public static Key<?> get(Type type)
```
    Gets a key for an injection type.
  - get
```
public static Key<?> get(Type type,
                         Class<? extends Annotation> annotationType)
```
    Gets a key for an injection type and an annotation type.
  - get
```
public static Key<?> get(Type type,
                         Annotation annotation)
```
    Gets a key for an injection type and an annotation.
  - get
```
public static <T> Key<T> get(TypeLiteral<T> typeLiteral)
```
    Gets a key for an injection type.
  - get
```
public static <T> Key<T> get(TypeLiteral<T> typeLiteral,
                             Class<? extends Annotation> annotationType)
```
    Gets a key for an injection type and an annotation type.
  - get
```
public static <T> Key<T> get(TypeLiteral<T> typeLiteral,
                             Annotation annotation)
```
    Gets a key for an injection type and an annotation.
  - ofType
```
public <T> Key<T> ofType(Class<T> type)
```
    Returns a new key of the specified type with the same annotation as this key.
    
    Since:
    
    3.0
  - ofType
```
public Key<?> ofType(Type type)
```
    Returns a new key of the specified type with the same annotation as this key.
    
    Since:
    
    3.0
  - ofType
```
public <T> Key<T> ofType(TypeLiteral<T> type)
```
    Returns a new key of the specified type with the same annotation as this key.
    
    Since:
    
    3.0
  - hasAttributes
```
public boolean hasAttributes()
```
    Returns true if this key has annotation attributes.
    
    Since:
    
    3.0
  - withoutAttributes
```
public Key<T> withoutAttributes()
```
    Returns this key without annotation attributes, i.e. with only the annotation type.
    
    Since:
    
    3.0

Class Key<T>

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Constructor Detail

Key

Key

Key

Method Detail

getTypeLiteral

getAnnotationType

getAnnotation

equals

hashCode

toString

get

get

get

get

get

get

get

get

get

ofType

ofType

ofType

hasAttributes

withoutAttributes