org.jbpm.pvm.internal.svc.RetryInterceptor.java Source code

Introduction

Here is the source code for org.jbpm.pvm.internal.svc.RetryInterceptor.java

Source

/*
 * JBoss, Home of Professional Open Source
 * Copyright 2005, JBoss Inc., and individual contributors as indicated
 * by the @authors tag. See the copyright.txt in the distribution for a
 * full listing of individual contributors.
 *
 * This is free software; you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License as
 * published by the Free Software Foundation; either version 2.1 of
 * the License, or (at your option) any later version.
 *
 * This software is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this software; if not, write to the Free
 * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
 * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
 */
package org.jbpm.pvm.internal.svc;

import org.jbpm.api.JbpmException;
import org.jbpm.internal.log.Log;
import org.jbpm.pvm.internal.cmd.Command;

import org.hibernate.StaleStateException;

/** retries the command execution in case hibernate throws optimistic locking 
 * (StaleObjectException) exceptions.
 * 
 * @author Tom Baeyens
 */
public class RetryInterceptor extends Interceptor {

    private static final Log log = Log.getLog(RetryInterceptor.class.getName());

    int retries = 3;
    long delay = 50;
    long delayFactor = 4;

    public <T> T execute(Command<T> command) {

        // TODO JBPM-2196 unify the retry code with the JtaTransactionInterceptor

        int attempt = 1;
        long sleepTime = delay;
        while (attempt <= retries) {
            if (attempt > 1) {
                log.trace("retrying...");
            }
            try {

                return next.execute(command);

            } catch (StaleStateException e) {
                attempt++;
                log.trace("optimistic locking failed: " + e);
                log.trace("waiting " + sleepTime + " millis");
                try {
                    Thread.sleep(sleepTime);
                } catch (InterruptedException e1) {
                    log.trace("retry sleeping got interrupted");
                }
                sleepTime *= delayFactor;
            }
        }
        throw new JbpmException("gave up after " + attempt + " attempts");
    }

    public int getRetries() {
        return retries;
    }

    public void setRetries(int retries) {
        this.retries = retries;
    }

    public long getDelay() {
        return delay;
    }

    public void setDelay(long delay) {
        this.delay = delay;
    }

    public long getDelayFactor() {
        return delayFactor;
    }

    public void setDelayFactor(long delayFactor) {
        this.delayFactor = delayFactor;
    }
}