CrawlViewResolver.java

package org.genedb.crawl.view;

import org.apache.log4j.Logger;
import org.springframework.core.Ordered;
import org.springframework.util.Assert;
import org.springframework.web.context.request.RequestAttributes;
import org.springframework.web.context.request.RequestContextHolder;
import org.springframework.web.context.request.ServletRequestAttributes;
import org.springframework.web.servlet.View;
import org.springframework.web.servlet.ViewResolver;

import java.util.Arrays;
import java.util.Locale;
import java.util.Map;

import javax.servlet.http.HttpServletRequest;

public class CrawlViewResolver implements ViewResolver, Ordered {

	private Logger logger = Logger.getLogger(CrawlViewResolver.class);

	private Map<String, View> viewMap;

	public void setViewMap(Map<String, View> viewMap) {
		this.viewMap = viewMap;
	}

	private int order;

	@Override
	public View resolveViewName(String viewName, Locale locale)
			throws Exception {

		String[] viewSplit = viewName.split(":");

		if (viewSplit.length < 1) {
			return null;
		}

		@SuppressWarnings("unused")
		String prefix = viewSplit[0];
		//logger.info(String.format("prefix: '%s'", prefix));

		String extensionViewName = "";
		if (viewSplit.length == 2) {
			extensionViewName = viewSplit[1];
		} else {
			extensionViewName = getExtension();
		}

		View view = viewMap.get(extensionViewName);
//		logger.info(String.format("Returning view of type '%s'",
//				view.getClass()));
		return view;
	}

	/**
	 * Generates and appropriate extension based on the existing HTTP request.
	 * 
	 * @param request
	 * @return
	 */
	private String getExtension() {

		RequestAttributes attrs = RequestContextHolder.getRequestAttributes();
		Assert.isInstanceOf(ServletRequestAttributes.class, attrs);
		ServletRequestAttributes servletAttrs = (ServletRequestAttributes) attrs;
		HttpServletRequest request = servletAttrs.getRequest();

		String uri = request.getRequestURI();
		String extension = "xml";
		if (uri.endsWith(".json")) {
			extension = "json";
		}
		
		StringBuilder sb = new StringBuilder (uri);
		String sep = " - ";
		@SuppressWarnings("unchecked")
		Map<String, String[]> parameters = request.getParameterMap();
    	for (Map.Entry<String, String[]> entry : parameters.entrySet()) {
    		sb.append(sep + entry.getKey() + " : " +  Arrays.asList(entry.getValue()).toString());
    		sep = ", ";
    	}
    	
    	logger.info(sb.toString());
		
		return extension;
	}

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

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

}