Package org.apache.maven.di

Class Key<T>

java.lang.Object

org.apache.maven.di.Key<T>

Type Parameters:

T - binding type

public abstract class Key<T>
extends Object

The key defines an identity of a binding. In any DI, a key is usually a type of the object along with some optional tag to distinguish between bindings which make objects of the same type.

In ActiveJ Inject, a key is also a type token - special abstract class that can store type information with the shortest syntax possible in Java.

For example, to create a key of type Map<String, List<Integer>>, you can just use this syntax: new Key<Map<String, List<Integer>>>(){}.

If your types are not known at compile time, you can use Types.parameterizedType(java.lang.reflect.Type, java.lang.reflect.Type, java.lang.reflect.Type[]) to make a parameterized type and give it to a Key.ofType constructor.

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	Key()
protected	Key(Object qualifier)
protected	Key(Type type, Object qualifier)

Method Summary

Modifier and Type	Method	Description
boolean	equals(Object o)
String	getDisplayString()	Returns an underlying type with display string formatting (package names stripped) and prepended qualifier display string if this key has a qualifier.
Object	getQualifier()
Class<T>	getRawType()	A shortcut for Types.getRawType(Type)(key.getType()).
Type	getType()
<U> Key<U>	getTypeParameter(int index)	Returns a type parameter of the underlying type wrapped as a key with no qualifier.
int	hashCode()
static <T> Key<T>	of(Class<T> type)
static <T> Key<T>	of(Class<T> type, Object qualifier)
static <T> Key<T>	ofType(Type type)
static <T> Key<T>	ofType(Type type, Object qualifier)
String	toString()

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Constructor Details

Key

protected Key()

Key

protected Key(@Nullable
 Object qualifier)

Key

protected Key(Type type,
 @Nullable
 Object qualifier)

Method Details

of

public static <T> Key<T> of(Class<T> type)

of

public static <T> Key<T> of(Class<T> type,
 @Nullable
 Object qualifier)

ofType

public static <T> Key<T> ofType(Type type)

ofType

public static <T> Key<T> ofType(Type type,
 @Nullable
 Object qualifier)

getType

public Type getType()

getRawType

public Class<T> getRawType()

A shortcut for Types.getRawType(Type)(key.getType()). Also casts the result to a properly parameterized class.

getTypeParameter

public <U> Key<U> getTypeParameter(int index)

Returns a type parameter of the underlying type wrapped as a key with no qualifier.

Throws:

IllegalStateException - when underlying type is not a parameterized one.

getQualifier

@Nullable
public Object getQualifier()

getDisplayString

public String getDisplayString()

Returns an underlying type with display string formatting (package names stripped) and prepended qualifier display string if this key has a qualifier.

equals

public boolean equals(Object o)

Overrides:

equals in class Object

hashCode

public int hashCode()

Overrides:

hashCode in class Object

toString

public String toString()

Overrides:

toString in class Object