rombert commented on code in PR #100: URL: https://github.com/apache/sling-org-apache-sling-resourceresolver/pull/100#discussion_r1324414773
########## src/main/java/org/apache/sling/resourceresolver/impl/FactoryRegistrationHandler.java: ########## @@ -0,0 +1,178 @@ +/* + * Licensed to the Apache Software Foundation (ASF) under one + * or more contributor license agreements. See the NOTICE file + * distributed with this work for additional information + * regarding copyright ownership. The ASF licenses this file + * to you 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.apache.sling.resourceresolver.impl; + +import org.apache.sling.api.resource.ResourceResolverFactory; +import org.apache.sling.api.resource.runtime.RuntimeService; +import org.osgi.framework.Bundle; +import org.osgi.framework.BundleContext; +import org.osgi.framework.Constants; +import org.osgi.framework.ServiceFactory; +import org.osgi.framework.ServiceRegistration; +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; + +import java.util.Dictionary; +import java.util.Hashtable; +import java.util.List; +import java.util.concurrent.ExecutorService; +import java.util.concurrent.Executors; +import java.util.concurrent.TimeUnit; + +public class FactoryRegistrationHandler implements AutoCloseable { + + private static final Logger LOG = LoggerFactory.getLogger(FactoryRegistrationHandler.class); + + private final ResourceResolverFactoryActivator activator; + + private final FactoryPreconditions factoryPreconditions; + + private final ExecutorService factoryRegistrationWorker; + + @SuppressWarnings("java:S3077") // The field is only ever set to null or to a new FactoryRegistration instance, which is safe. + private volatile FactoryRegistration factoryRegistration; + + public FactoryRegistrationHandler( + ResourceResolverFactoryActivator activator, FactoryPreconditions factoryPreconditions) { + this.factoryPreconditions = factoryPreconditions; + this.activator = activator; + this.factoryRegistrationWorker = Executors.newSingleThreadExecutor( + r -> new Thread(r, "ResourceResolverFactory registration/deregistration")); + } + + @Override + public void close() { + unregisterFactory(); + factoryRegistrationWorker.shutdown(); + try { + if (!factoryRegistrationWorker.awaitTermination(5, TimeUnit.SECONDS)) { + final List<Runnable> runnables = factoryRegistrationWorker.shutdownNow(); + if (runnables.size() >= 2) { Review Comment: This deserves a comment/method, I can't tell why we check for more than two runnables or why we ignore the first two. ########## src/main/java/org/apache/sling/resourceresolver/impl/FactoryRegistrationHandler.java: ########## @@ -0,0 +1,178 @@ +/* + * Licensed to the Apache Software Foundation (ASF) under one + * or more contributor license agreements. See the NOTICE file + * distributed with this work for additional information + * regarding copyright ownership. The ASF licenses this file + * to you 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.apache.sling.resourceresolver.impl; + +import org.apache.sling.api.resource.ResourceResolverFactory; +import org.apache.sling.api.resource.runtime.RuntimeService; +import org.osgi.framework.Bundle; +import org.osgi.framework.BundleContext; +import org.osgi.framework.Constants; +import org.osgi.framework.ServiceFactory; +import org.osgi.framework.ServiceRegistration; +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; + +import java.util.Dictionary; +import java.util.Hashtable; +import java.util.List; +import java.util.concurrent.ExecutorService; +import java.util.concurrent.Executors; +import java.util.concurrent.TimeUnit; + +public class FactoryRegistrationHandler implements AutoCloseable { + + private static final Logger LOG = LoggerFactory.getLogger(FactoryRegistrationHandler.class); + + private final ResourceResolverFactoryActivator activator; + + private final FactoryPreconditions factoryPreconditions; + + private final ExecutorService factoryRegistrationWorker; + + @SuppressWarnings("java:S3077") // The field is only ever set to null or to a new FactoryRegistration instance, which is safe. + private volatile FactoryRegistration factoryRegistration; + + public FactoryRegistrationHandler( + ResourceResolverFactoryActivator activator, FactoryPreconditions factoryPreconditions) { + this.factoryPreconditions = factoryPreconditions; + this.activator = activator; + this.factoryRegistrationWorker = Executors.newSingleThreadExecutor( + r -> new Thread(r, "ResourceResolverFactory registration/deregistration")); + } + + @Override + public void close() { + unregisterFactory(); + factoryRegistrationWorker.shutdown(); + try { + if (!factoryRegistrationWorker.awaitTermination(5, TimeUnit.SECONDS)) { + final List<Runnable> runnables = factoryRegistrationWorker.shutdownNow(); + if (runnables.size() >= 2) { + final Runnable unregisterTask = runnables.get(runnables.size() - 2); + unregisterTask.run(); + } + } + } catch (InterruptedException e) { + Thread.currentThread().interrupt(); + } + } + + /** + * Check the preconditions and if it changed, either register factory or unregister + */ + void maybeRegisterFactory(final String unavailableName, final String unavailableServicePid) { + if (!factoryRegistrationWorker.isShutdown()) { + LOG.debug("submitting maybeRegisterFactory"); + factoryRegistrationWorker.submit(() -> { + final boolean preconditionsOk = factoryPreconditions.checkPreconditions(unavailableName, unavailableServicePid); + if ( preconditionsOk && this.factoryRegistration == null ) { + // check system bundle state - if stopping, don't register new factory + final Bundle systemBundle = activator.getBundleContext().getBundle(Constants.SYSTEM_BUNDLE_LOCATION); + if ( systemBundle != null && systemBundle.getState() != Bundle.STOPPING ) { + withThreadName("ResourceResolverFactory registration", this::doRegisterFactory); + } + } else if ( !preconditionsOk && this.factoryRegistration != null ) { + LOG.debug("performing unregisterFactory via maybeRegisterFactory"); + withThreadName("ResourceResolverFactory deregistration", this::doUnregisterFactory); + } + }); + } + } + + void unregisterFactory() { + LOG.debug("submitting unregisterFactory"); + factoryRegistrationWorker.submit(() -> withThreadName("ResourceResolverFactory deregistration", + this::doUnregisterFactory)); + } + + /** + * Register the factory. + */ + private void doRegisterFactory() { + LOG.debug("performing registerFactory, factoryRegistration == {}", factoryRegistration); + if (this.factoryRegistration == null) { + this.factoryRegistration = new FactoryRegistration(activator.getBundleContext(), activator); + } + LOG.debug("finished performing registerFactory, factoryRegistration == {}", factoryRegistration); + } + + /** + * Unregister the factory (if registered). + */ + private void doUnregisterFactory() { + LOG.debug("performing unregisterFactory, factoryRegistration == {}", factoryRegistration); + if (this.factoryRegistration != null) { + this.factoryRegistration.unregister(); + this.factoryRegistration = null; + } + LOG.debug("finished performing unregisterFactory, factoryRegistration == {}", factoryRegistration); + } + + private static void withThreadName(String threadName, Runnable task) { + final String name = Thread.currentThread().getName(); Review Comment: Are you trying to expose what is going on via the thread name? It might be better for observability to keep a stable thread name prefix and reflect the current task in the second part, e.g. `getClass().getSimpleName() + " - " threadName` -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected]
