MartinKanters commented on a change in pull request #476: URL: https://github.com/apache/maven/pull/476#discussion_r646850578
########## File path: maven-core/src/main/java/org/apache/maven/execution/LockingEventSpy.java ########## @@ -0,0 +1,96 @@ +package org.apache.maven.execution; + +/* + * 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. + */ + +import java.util.Map; +import java.util.concurrent.ConcurrentHashMap; +import java.util.concurrent.locks.Lock; +import java.util.concurrent.locks.ReentrantLock; + +import javax.inject.Named; +import javax.inject.Singleton; + +import org.apache.maven.eventspy.AbstractEventSpy; +import org.apache.maven.eventspy.EventSpy; +import org.apache.maven.project.MavenProject; +import org.eclipse.aether.SessionData; +import org.eclipse.sisu.Typed; +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; + +/** + * EventSpy implementation that provides a per-project locking mechanism + * to make sure a given project can not be build twice concurrently. + * This case can happen when running parallel builds with forked lifecycles. + */ +@Singleton +@Named +@Typed( EventSpy.class ) +public class LockingEventSpy extends AbstractEventSpy Review comment: It's definitely less intrusive, but I'm not sure whether something that controls the build as much as this (temporarily pausing and resuming project builds) should be done in an `ExecutionListener` or `EventSpy`. My gut feeling says those classes should only extend the build with simple side-effects, like logging a project's phase. I would prefer your last suggestion. Then again, maybe this is the right direction. Perhaps some others can give their opinion on it? -- 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. For queries about this service, please contact Infrastructure at: us...@infra.apache.org
