OsgiExtensionPointViewResolver.java

/*
 * Copyright: (c) 2004-2012 Mayo Foundation for Medical Education and 
 * Research (MFMER). All rights reserved. MAYO, MAYO CLINIC, and the
 * triple-shield Mayo logo are trademarks and service marks of MFMER.
 *
 * Except as contained in the copyright notice above, or as used to identify 
 * MFMER as the author of this software, the trade names, trademarks, service
 * marks, or product names of the copyright holder shall not be used in
 * advertising, promotion or otherwise in connection with this software without
 * prior written authorization of the copyright holder.
 *
 * 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 edu.mayo.cts2.framework.webapp.rest.osgi;

import java.util.Locale;

import org.osgi.util.tracker.ServiceTrackerCustomizer;
import org.springframework.core.Ordered;
import org.springframework.web.servlet.View;
import org.springframework.web.servlet.ViewResolver;

import edu.mayo.cts2.framework.core.plugin.AbstractExtensionPoint;

/**
 * An extension point to cycle through registered ViewResolvers Services
 * in OSGi bundles.
 *
 * @author <a href="mailto:kevin.peterson@mayo.edu">Kevin Peterson</a>
 */
public class OsgiExtensionPointViewResolver 
	extends AbstractExtensionPoint<ViewResolver> 
	implements ViewResolver, Ordered {
	
	private int order = Integer.MAX_VALUE;

	/* (non-Javadoc)
	 * @see org.springframework.web.servlet.ViewResolver#resolveViewName(java.lang.String, java.util.Locale)
	 */
	@Override
	public View resolveViewName(String viewName, Locale locale)
			throws Exception {
		Object[] viewResolvers = this.getServiceTracker().getServices();
		if(viewResolvers != null){
			for(Object resolver : viewResolvers){
				View view = ((ViewResolver)resolver).resolveViewName(viewName, locale);
			
				if(view != null){
					return view;
				}
			}
		}
		
		return null;
	}

	/* (non-Javadoc)
	 * @see edu.mayo.cts2.framework.core.plugin.ExtensionPoint#getServiceClass()
	 */
	@Override
	public Class<?> getServiceClass() {
		return ViewResolver.class;
	}

	/* (non-Javadoc)
	 * @see edu.mayo.cts2.framework.core.plugin.ExtensionPoint#addServiceTrackerCustomizer()
	 */
	@Override
	public ServiceTrackerCustomizer addServiceTrackerCustomizer() {
		return null;
	}

	@Override
	public int getOrder() {
		return this.order;
	}

	public void setOrder(int order) {
		this.order = order;
	}
}