com.hazelcast.internal.namespace.impl.NodeEngineThreadLocalContext Maven / Gradle / Ivy
/*
* Copyright (c) 2008-2024, Hazelcast, Inc. All Rights Reserved.
*
* 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 com.hazelcast.internal.namespace.impl;
import com.hazelcast.spi.impl.NodeEngine;
/**
* A thread-local context that maintains a {@link NodeEngine} instance to be retrieved in
* areas of execution where Namespace awareness is required, which needs a {@link NodeEngine}
* instance to access the {@link NodeEngine#getNamespaceService()} method, but there is
* no local variable available.
*
* The use of this thread-local context allows us to reduce code complexity that would otherwise
* be introduced by passing {@link NodeEngine} references through long function chains.
*/
public final class NodeEngineThreadLocalContext {
private static final ThreadLocal NE_THREAD_LOCAL = new ThreadLocal<>();
private NodeEngineThreadLocalContext() {
}
/**
* Sets the provided {@link NodeEngine} reference as this thread's {@link ThreadLocal}
* instance for use in Namespace awareness.
*
* @param nodeEngine the {@link NodeEngine} reference to use.
*/
public static void declareNodeEngineReference(NodeEngine nodeEngine) {
if (nodeEngine != null) {
NE_THREAD_LOCAL.set(nodeEngine);
}
}
/**
* Removes the currently set {@link NodeEngine} reference for this thread.
*/
public static void destroyNodeEngineReference() {
NE_THREAD_LOCAL.remove();
}
/**
* Retrieves the currently set {@link NodeEngine} reference for this thread,
* or throws an {@link IllegalStateException} if one could not be found.
*
* @return This thread's {@link NodeEngine} reference.
*/
public static NodeEngine getNodeEngineThreadLocalContext() {
NodeEngine tlContext = NE_THREAD_LOCAL.get();
if (tlContext == null) {
throw new IllegalStateException("NodeEngine context is not available for Namespaces! Current thread: "
+ Thread.currentThread().getName() + " (" + Thread.currentThread().getId() + ")");
} else {
return tlContext;
}
}
/**
* Retrieves the currently set {@link NodeEngine} reference for this thread,
* or {@code null} if one could not be found.
*
* @return This thread's {@link NodeEngine} reference if available, or {@code null}.
*/
public static NodeEngine getNodeEngineThreadLocalContextOrNull() {
NodeEngine tlContext = NE_THREAD_LOCAL.get();
if (tlContext == null) {
return null;
} else {
return tlContext;
}
}
}