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/*
* Copyright (c) 2011, 2019 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.jersey.internal.inject;
import java.util.function.Supplier;
import javax.inject.Provider;
import org.glassfish.jersey.internal.util.collection.Ref;
import org.glassfish.jersey.internal.util.collection.Refs;
/**
* Factory that provides injection of the referenced instance.
*
* @param
* @author Marek Potociar
*/
public abstract class ReferencingFactory implements Supplier {
private static class EmptyReferenceFactory implements Supplier> {
@Override
public Ref get() {
return Refs.emptyRef();
}
}
private static class InitializedReferenceFactory implements Supplier> {
private final T initialValue;
public InitializedReferenceFactory(T initialValue) {
this.initialValue = initialValue;
}
@Override
public Ref get() {
return Refs.of(initialValue);
}
}
private final Provider> referenceFactory;
/**
* Create new referencing injection factory.
*
* @param referenceFactory reference provider backing the factory.
*/
public ReferencingFactory(Provider> referenceFactory) {
this.referenceFactory = referenceFactory;
}
@Override
public T get() {
return referenceFactory.get().get();
}
/**
* Get a reference factory providing an empty reference.
*
* @param reference type.
* @return reference factory providing an empty reference.
*/
public static Supplier> referenceFactory() {
return new EmptyReferenceFactory<>();
}
/**
* Get a reference factory providing an initialized reference.
*
* @param reference type.
* @param initialValue initial value stored in the reference provided
* by the returned factory.
* @return reference factory providing a reference initialized with an
* {@code initialValue}.
*/
public static Supplier> referenceFactory(T initialValue) {
if (initialValue == null) {
return new EmptyReferenceFactory<>();
}
return new InitializedReferenceFactory<>(initialValue);
}
}