org.springframework.webflow.conversation.impl.ConversationLockFactory Maven / Gradle / Ivy
/*
* Copyright 2002-2006 the original author or authors.
*
* 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.springframework.webflow.conversation.impl;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.springframework.core.JdkVersion;
/**
* Simple utility class for creating conversation lock instances based on the
* current execution environment.
*
* @author Keith Donald
* @author Rob Harrop
*/
public class ConversationLockFactory {
private static final Log logger = LogFactory.getLog(ConversationLockFactory.class);
private static boolean utilConcurrentPresent;
static {
try {
Class.forName("EDU.oswego.cs.dl.util.concurrent.ReentrantLock");
utilConcurrentPresent = true;
}
catch (ClassNotFoundException ex) {
utilConcurrentPresent = false;
}
}
/**
* When running on Java 1.5+, returns a jdk5 concurrent lock. When running on older JDKs with
* the 'util.concurrent' package available, returns a util concurrent lock.
* In all other cases a "no-op" lock is returned.
*/
public static ConversationLock createLock() {
if (JdkVersion.getMajorJavaVersion() >= JdkVersion.JAVA_15) {
return new JdkConcurrentConversationLock();
}
else if (utilConcurrentPresent) {
return new UtilConcurrentConversationLock();
}
else {
logger.warn("Unable to enable conversation locking. Switch to Java 5 or above, "
+ "or put the 'util.concurrent' package on the classpath "
+ "to enable locking in your environment.");
return NoOpConversationLock.INSTANCE;
}
}
}