madrob commented on a change in pull request #2291: URL: https://github.com/apache/lucene-solr/pull/2291#discussion_r568977953
########## File path: solr/core/src/test/org/apache/solr/cluster/CountingStateChangeListener.java ########## @@ -0,0 +1,68 @@ +/* + * 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.solr.cluster; + +import org.apache.solr.common.util.TimeSource; +import org.apache.solr.util.TimeOut; + +import java.util.concurrent.TimeUnit; +import java.util.concurrent.TimeoutException; + +/** + * A counting StateChangeListener that will internally track how many times {@link #stateChanged()} has been called. + * Consumers can compare the number of state change calls before and after an event to determine if they should proceed, + * made simple with {@link #waitForVersionChange(int, int)} method. + */ +public class CountingStateChangeListener implements StateChangeListener { + private int version = 0; + + @Override + public synchronized void stateChanged() { + version++; + this.notifyAll(); + } + + /** + * Given a last known number of state changes, wait for additional changes to come in. If no state changes have + * occurred beyond the known value, this method will wait for additional changes to come in. + * If the current number of change events is unknown to the caller, then this method can be called with <tt>-1</tt> + * to return immediately with the number of events up to this point. + * @param lastVersion the previous number of changes seen + * @param timeoutSec how long to wait for additional changes to occur + * @return the number of changes seen since initialization + */ + public int waitForVersionChange(int lastVersion, int timeoutSec) throws InterruptedException, TimeoutException { + TimeOut timeout = new TimeOut(timeoutSec, TimeUnit.SECONDS, TimeSource.NANO_TIME); + int newVersion = lastVersion; + synchronized (this) { + while (!timeout.hasTimedOut() && (newVersion = version) != lastVersion) { Review comment: It's a copy-paste error ---------------------------------------------------------------- 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 --------------------------------------------------------------------- To unsubscribe, e-mail: issues-unsubscr...@lucene.apache.org For additional commands, e-mail: issues-h...@lucene.apache.org
