/* 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.camunda.bpm.engine.spring.application;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.servlet.ServletContext;
import org.camunda.bpm.application.AbstractProcessApplication;
import org.camunda.bpm.application.ProcessApplicationElResolver;
import org.camunda.bpm.application.impl.EjbProcessApplication;
import org.camunda.bpm.application.impl.ServletProcessApplication;
import org.camunda.bpm.engine.impl.javax.el.ELResolver;
import org.camunda.bpm.engine.spring.ApplicationContextElResolver;
import org.springframework.util.ClassUtils;
import org.springframework.web.context.WebApplicationContext;
import org.springframework.web.context.support.WebApplicationContextUtils;
/**
* <p>ProcessApplicationElResolver implementation providing support for the Spring Framework.</p>
*
* <p>This implementation supports the following environments:
* <ul>
* <li>Bootstrapping through {@link SpringProcessApplication}. In this case the spring application context
* is retrieved from the {@link SpringProcessApplication} class.</li>
* <li>Bootstrapping through {@link ServletProcessApplication}. In this case we have access to the {@link ServletContext}
* which allows accessing the web application's application context through the WebApplicationContextUtils class.</li>
* </li>
* </ul>
* </p>
*
* <p><strong>Limitation</strong>: The {@link EjbProcessApplication} is currently unsupported.</p>
*
* @author Daniel Meyer
*
*/
public class SpringProcessApplicationElResolver implements ProcessApplicationElResolver {
private final static Logger LOGGER = Logger.getLogger(SpringProcessApplicationElResolver.class.getName());
public Integer getPrecedence() {
return ProcessApplicationElResolver.SPRING_RESOLVER;
}
public ELResolver getElResolver(AbstractProcessApplication processApplication) {
if (processApplication instanceof SpringProcessApplication) {
SpringProcessApplication springProcessApplication = (SpringProcessApplication) processApplication;
return new ApplicationContextElResolver(springProcessApplication.getApplicationContext());
} else if (processApplication instanceof ServletProcessApplication) {
ServletProcessApplication servletProcessApplication = (ServletProcessApplication) processApplication;
if(!ClassUtils.isPresent("org.springframework.web.context.support.WebApplicationContextUtils", processApplication.getProcessApplicationClassloader())) {
LOGGER.log(Level.FINE, "WebApplicationContextUtils must be present for SpringProcessApplicationElResolver to work");
return null;
}
ServletContext servletContext = servletProcessApplication.getServletContext();
WebApplicationContext applicationContext = WebApplicationContextUtils.getWebApplicationContext(servletContext);
if(applicationContext != null) {
return new ApplicationContextElResolver(applicationContext);
}
}
LOGGER.log(Level.FINE, "Process application class {0} unsupported by SpringProcessApplicationElResolver", processApplication);
return null;
}
}