org.glassfish.hk2.api.InjectionResolver Maven / Gradle / Ivy
/*
* Copyright (c) 2012, 2018 Oracle and/or its affiliates. All rights reserved.
*
* This program and the accompanying materials are made available under the
* terms of the Eclipse Public License v. 2.0, which is available at
* http://www.eclipse.org/legal/epl-2.0.
*
* This Source Code may also be made available under the following Secondary
* Licenses when the conditions for such availability set forth in the
* Eclipse Public License v. 2.0 are satisfied: GNU General Public License,
* version 2 with the GNU Classpath Exception, which is available at
* https://www.gnu.org/software/classpath/license.html.
*
* SPDX-License-Identifier: EPL-2.0 OR GPL-2.0 WITH Classpath-exception-2.0
*/
package org.glassfish.hk2.api;
import org.jvnet.hk2.annotations.Contract;
/**
* This class allows users to provide a custom injection target for
* any annotation (including @Inject). The user would usually
* only provide a resolver for @Inject if it were specializing
* the system provided resolver for @Inject. Otherwise, this
* resolver can be used to provide injection points for any annotation.
*
* An implementation of InjectionResolver must be in the Singleton scope.
* Implementations of InjectionResolver will be instantiated as soon as
* they are added to HK2 in order to avoid deadlocks and circular references.
* Therefore it is recommended that implementations of InjectionResolver
* make liberal use of {@link jakarta.inject.Provider} or {@link IterableProvider}
* when injecting dependent services so that these services are not instantiated
* when the InjectionResolver is created
*
* @author jwells
* @param This must be the class of the injection annotation that this resolver
* will handle
*/
@Contract
public interface InjectionResolver {
/** This is the name of the system provided resolver for 330 injections */
public final static String SYSTEM_RESOLVER_NAME = "SystemInjectResolver";
/**
* This method will return the object that should be injected into the given
* injection point. It is the responsiblity of the implementation to ensure that
* the object returned can be safely injected into the injection point.
*
* This method should not do the injection themselves
*
* @param injectee The injection point this value is being injected into
* @param root The service handle of the root class being created, which should
* be used in order to ensure proper destruction of associated &64;PerLookup
* scoped objects. This can be null in the case that this is being used
* for an object not managed by HK2. This will only happen if this
* object is being created with the create method of ServiceLocator.
* @return A possibly null value to be injected into the given injection point
*/
public Object resolve(Injectee injectee, ServiceHandle root);
/**
* This method should return true if the annotation that indicates that this is
* an injection point can appear in the parameter list of a constructor.
*
* @return true if the injection annotation can appear in the parameter list of
* a constructor
*/
public boolean isConstructorParameterIndicator();
/**
* This method should return true if the annotation that indicates that this is
* an injection point can appear in the parameter list of a method.
*
* @return true if the injection annotation can appear in the parameter list of
* a method
*/
public boolean isMethodParameterIndicator();
}