circuitbreaker/web/CircuitBreakerServletBase.java

package dk.thoerup.circuitbreaker.web;

import java.io.IOException;

import javax.servlet.ServletException;
import javax.servlet.http.*;

/**
 * This is a web interface for viewing and controlling the CircuitBreakers currently registered in CircuitBreakerManager
 * <p> 
 * To use this servlet in you .war module just create a simple servlet that extends this class (instead of HttpServlet)
 * The new custom servlet doesn't need to implement any of the standard servlet methods - its all done in this implementation.
 *  
 * <p>
 * Example:
 * <pre>
 * public class CircuitBreakerServlet extends CircuitBreakerServletBase {
 *   private static final long serialVersionUID = 1L;
 * }
 * </pre>
 * 
 * If you add a servlet init pameter to your deployment descriptor with the name 'readonly' and a integer value > 0,  you can disable the 
 * control buttons:
 * <p>
 *   &lt;init-param>&lt;param-name>readonly&lt;/param-name>&lt;param-value>1&lt;/param-value>&lt;/init-param>
 *   <!-- <init-param><param-name>readonly</param-name><param-value>1</param-value></init-param> -->
 * 
 */

public class CircuitBreakerServletBase  extends javax.servlet.http.HttpServlet  {
        
        private static final long serialVersionUID = 1L;
        
        private boolean readOnly = false;
        
        
        
        @Override
        public void init() throws ServletException {
                super.init();
                
                String readOnlyStr = getInitParameter("readonly");
                if (readOnlyStr != null && readOnlyStr.trim().length() >0) {
                        int readOnlyInt = Integer.parseInt(readOnlyStr.trim());
                        readOnly = (readOnlyInt > 0);
                }
        }

        private Command getCommand(String command) throws ServletException {
                if (command == null || command.equals("list"))
                        return new ListCircuitBreakers();
                
                if (command.equals("view"))
                        return new ViewCircuitBreaker(readOnly);
                if (command.equals("action"))
                        return new ActionCommand(readOnly);
                if (command.equals("log"))
                        return new LogViewCommand();
                
                throw new ServletException("No such command:" + command);
        }

        @Override
        public void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
                Command cmd = getCommand( req.getParameter("command"));
                
                String response = cmd.execute(req,resp);
                
                resp.setDateHeader("Expires", 0);
                resp.setHeader("Pragma", "no-cache");
                resp.setHeader("Cache-Control", "no-cache");
                resp.setContentType("text/html");
                
                resp.getWriter().print(response);
        }

        @Override
        protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
                doGet(req, resp);
        }

}
1	torben	467	package dk.thoerup.circuitbreaker.web;
2	torben	411
3			import java.io.IOException;
4
5			import javax.servlet.ServletException;
6			import javax.servlet.http.*;
7
8			/**
9			* This is a web interface for viewing and controlling the CircuitBreakers currently registered in CircuitBreakerManager
10			* <p>
11	torben	414	* To use this servlet in you .war module just create a simple servlet that extends this class (instead of HttpServlet)
12			* The new custom servlet doesn't need to implement any of the standard servlet methods - its all done in this implementation.
13			*
14			* <p>
15	torben	411	* Example:
16			* <pre>
17	torben	414	* public class CircuitBreakerServlet extends CircuitBreakerServletBase {
18	torben	411	* private static final long serialVersionUID = 1L;
19			* }
20			* </pre>
21	torben	417	*
22			* If you add a servlet init pameter to your deployment descriptor with the name 'readonly' and a integer value > 0, you can disable the
23			* control buttons:
24			* <p>
25			* <init-param><param-name>readonly</param-name><param-value>1</param-value></init-param>
26			* <!-- <init-param><param-name>readonly</param-name><param-value>1</param-value></init-param> -->
27			*
28	torben	411	*/
29
30	torben	416	public class CircuitBreakerServletBase extends javax.servlet.http.HttpServlet {
31	torben	411
32	torben	414	private static final long serialVersionUID = 1L;
33	torben	416
34	torben	417	private boolean readOnly = false;
35
36
37
38			@Override
39			public void init() throws ServletException {
40			super.init();
41
42			String readOnlyStr = getInitParameter("readonly");
43			if (readOnlyStr != null && readOnlyStr.trim().length() >0) {
44			int readOnlyInt = Integer.parseInt(readOnlyStr.trim());
45			readOnly = (readOnlyInt > 0);
46			}
47			}
48
49	torben	416	private Command getCommand(String command) throws ServletException {
50			if (command == null \|\| command.equals("list"))
51			return new ListCircuitBreakers();
52
53			if (command.equals("view"))
54	torben	417	return new ViewCircuitBreaker(readOnly);
55			if (command.equals("action"))
56			return new ActionCommand(readOnly);
57	torben	1291	if (command.equals("log"))
58			return new LogViewCommand();
59	torben	416
60	torben	417	throw new ServletException("No such command:" + command);
61	torben	416	}
62	torben	414
63	torben	424	@Override
64	torben	411	public void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
65	torben	416	Command cmd = getCommand( req.getParameter("command"));
66	torben	411
67	torben	416	String response = cmd.execute(req,resp);
68	torben	411
69			resp.setDateHeader("Expires", 0);
70			resp.setHeader("Pragma", "no-cache");
71			resp.setHeader("Cache-Control", "no-cache");
72	torben	423	resp.setContentType("text/html");
73	torben	411
74			resp.getWriter().print(response);
75			}
76
77	torben	416	@Override
78			protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
79			doGet(req, resp);
80			}
81
82	torben	411	}