MetricServicesServlet.java

package us.mn.state.health.lims.metricservice.action;

import java.io.IOException;
import java.io.PrintWriter;
import java.lang.management.ManagementFactory;
import java.lang.management.MemoryPoolMXBean;
import java.util.List;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class MetricServicesServlet extends HttpServlet {

	private static final long serialVersionUID = 947483610606055973L;

	/**
	 * Constructor of the object.
	 */
	public MetricServicesServlet() {
		super();
	}

	/**
	 * Destruction of the servlet. <br>
	 */
	public void destroy() {
		super.destroy(); // Just puts "destroy" string in log
		// Put your code here
	}

	/**
	 * The doGet method of the servlet. <br>
	 *
	 * This method is called when a form has its tag value method equals to get.
	 *
	 * @param request
	 *            the request send by the client to the server
	 * @param response
	 *            the response send by the server to the client
	 * @throws ServletException
	 *             if an error occurred
	 * @throws IOException
	 *             if an error occurred
	 */
	public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

		String permGen = getAvailablePermGen();
		response.setContentType("text/xml");
		PrintWriter out = response.getWriter();

		out.println("<?xml version = \"1.0\" encoding = \"utf-8\"?>");
		out.println("<metrics>");
		out.println("<permgen>");
		out.println(permGen);
		out.println("</permgen>");
		out.println("</metrics>");
		out.flush();
		out.close();
	}

	private String getAvailablePermGen() {

		List<MemoryPoolMXBean> memoryList = ManagementFactory.getMemoryPoolMXBeans();

		for (MemoryPoolMXBean memory : memoryList) {
			if (memory.getName().contains("Perm Gen")) {
				return String.valueOf((int)(((double)(memory.getUsage().getMax() - memory.getUsage().getUsed())) / 1024.0));
			}
		}
		return "0";
	}

	/**
	 * The doPost method of the servlet. <br>
	 *
	 * This method is called when a form has its tag value method equals to
	 * post.
	 *
	 * @param request
	 *            the request send by the client to the server
	 * @param response
	 *            the response send by the server to the client
	 * @throws ServletException
	 *             if an error occurred
	 * @throws IOException
	 *             if an error occurred
	 */
	public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

		response.setContentType("text/html");
		PrintWriter out = response.getWriter();

	
		out.close();
	}

	/**
	 * Initialization of the servlet. <br>
	 *
	 * @throws ServletException
	 *             if an error occurs
	 */
	public void init() throws ServletException {
		// Put your code here
	}

}