LazilyInitialized.java
/*
* Copyright 2021 Red Hat, Inc. and/or its affiliates
* and other contributors as indicated by the @author tags.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.keycloak.models.map.common.delegate;
import java.util.concurrent.atomic.AtomicMarkableReference;
import java.util.function.Supplier;
/**
*
* @author hmlnarik
*/
public class LazilyInitialized<T> {
private final Supplier<T> supplier;
private final AtomicMarkableReference<T> supplierRef = new AtomicMarkableReference<>(null, false);
public LazilyInitialized(Supplier<T> supplier) {
this.supplier = supplier;
}
public T get() {
if (! isInitialized()) {
supplierRef.compareAndSet(null, supplier == null ? null : supplier.get(), false, true);
}
return supplierRef.getReference();
}
/**
* Returns {@code true} if the reference to the object has been initialized
* @return
*/
public boolean isInitialized() {
return supplierRef.isMarked();
}
}