Revert a DateVariable (ThreadSave)

If the DateToStringConverter will revert more than one Date in diffrent threads in the same time. Runtime excetion (NumberFormat....) will be thrown.
The SimpleDateFormat is not thread save!

Solution is:

/*

• 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 de.isr.bpm.jbpm.internal;

import java.text.DateFormat;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Date;

import org.jbpm.api.JbpmException;
import org.jbpm.pvm.internal.model.ScopeInstanceImpl;
import org.jbpm.pvm.internal.type.Converter;
import org.jbpm.pvm.internal.type.Variable;

/**

• @author Tom Baeyens
  */
  public class DateToStringConverter implements Converter {

private static final long serialVersionUID = 1L;
String format = "yyyy-MM-dd HH:mm:ss,SSS";

public Object convert(Object o, ScopeInstanceImpl scopeInstance, Variable variable)

{ DateFormat dateFormat = new SimpleDateFormat(format); return dateFormat.format((Date)o); }

public Object revert(Object o, ScopeInstanceImpl scopeInstance, Variable variable) {
try

{ DateFormat dateFormat = new SimpleDateFormat(format); return dateFormat.parseObject((String)o); }

catch (ParseException e)

{ throw new JbpmException("invalid date format in date variable: "+o, e); }

}

public boolean supports(Object value, ScopeInstanceImpl scopeInstance, Variable variable)

{ return ((value!=null) && (value instanceof Date)); }

public void setFormat(String format)

{ this.format = format; }

}