VelocityExceptionHandler.java

/**
 * This Source Code Form is subject to the terms of the Mozilla Public License,
 * v. 2.0. If a copy of the MPL was not distributed with this file, You can
 * obtain one at http://mozilla.org/MPL/2.0/. OpenMRS is also distributed under
 * the terms of the Healthcare Disclaimer located at http://openmrs.org/license.
 *
 * Copyright (C) OpenMRS Inc. OpenMRS is a registered trademark and the OpenMRS
 * graphic logo is a trademark of OpenMRS Inc.
 */
package org.openmrs.util;

import org.apache.velocity.app.event.MethodExceptionEventHandler;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * Class to safely catch velocity exceptions
 */
public class VelocityExceptionHandler implements MethodExceptionEventHandler {
	
	private Logger log = LoggerFactory.getLogger(this.getClass());
	
	/**
	 * When a user-supplied method throws an exception, the MethodExceptionEventHandler is invoked
	 * with the Class, method name and thrown Exception. The handler can either return a valid
	 * Object to be used as the return value of the method call, or throw the passed-in or new
	 * Exception, which will be wrapped and propagated to the user as a MethodInvocationException
	 *
	 * @see org.apache.velocity.app.event.MethodExceptionEventHandler#methodException(java.lang.Class,
	 *      java.lang.String, java.lang.Exception)
	 */
	@Override
	public Object methodException(Class claz, String method, Exception e) throws Exception {
		
		log.debug("Claz: " + claz.getName() + " method: " + method, e);
		
		// if formatting a date (and probably getting an "IllegalArgumentException")
		if ("format".equals(method)) {
			return null;
		}
		
		// keep the default behavior
		throw e;
	}
	
}