com.google.inject.Scope Maven / Gradle / Ivy
package com.google.inject;
/**
* A scope is a level of visibility that instances provided by Guice may have.
* By default, an instance created by the {@link Injector} has no scope,
* meaning it has no state from the framework's perspective -- the
* {@code Injector} creates it, injects it once into the class that required it,
* and then immediately forgets it. Associating a scope with a particular
* binding allows the created instance to be "remembered" and possibly used
* again for other injections.
*
* An example of a scope is {@link Scopes#SINGLETON}.
*/
public interface Scope {
/**
* Scopes a provider. The returned provider returns objects from this scope.
* If an object does not exist in this scope, the provider can use the given
* unscoped provider to retrieve one.
*
*
Scope implementations are strongly encouraged to override
* {@link Object#toString} in the returned provider and include the backing
* provider's {@code toString()} output.
*
* @param key binding key
* @param unscoped locates an instance when one doesn't already exist in this
* scope.
* @return a new provider which only delegates to the given unscoped provider
* when an instance of the requested object doesn't already exist in this
* scope
*/
public Provider scope(Key key, Provider unscoped);
/**
* A short but useful description of this scope. For comparison, the standard
* scopes that ship with guice use the descriptions
* {@code "Scopes.SINGLETON"}, {@code "ServletScopes.SESSION"} and
* {@code "ServletScopes.REQUEST"}.
*/
String toString();
}