circuitbreaker/web/CircuitBreakerServletBase.java

package dk.thoerup.circuitbreaker.web;

import java.io.IOException;

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

/**
 * 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> -->
 *   
 *  You could also configure it dynamically from a ContextListener:
 *  ServletRegistration.Dynamic dynconf = sce.getServletContext().addServlet("circuitbreaker", dk.thoerup.circuitbreaker.web.CircuitBreakerServletBase.class );
 *  dynconf.addMapping("/CircuitBreakerServlet");
 *  dynconf.setInitParameter("readonly", "1");
 * 
 */

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	package dk.thoerup.circuitbreaker.web;
2
3	import java.io.IOException;
4
5	import javax.servlet.ServletException;
6	import javax.servlet.http.HttpServletRequest;
7	import javax.servlet.http.HttpServletResponse;
8
9	/**
10	* This is a web interface for viewing and controlling the CircuitBreakers currently registered in CircuitBreakerManager
11	* <p>
12	* To use this servlet in you .war module just create a simple servlet that extends this class (instead of HttpServlet)
13	* The new custom servlet doesn't need to implement any of the standard servlet methods - its all done in this implementation.
14	*
15	* <p>
16	* Example:
17	* <pre>
18	* public class CircuitBreakerServlet extends CircuitBreakerServletBase {
19	* private static final long serialVersionUID = 1L;
20	* }
21	* </pre>
22	*
23	* If you add a servlet init pameter to your deployment descriptor with the name 'readonly' and a integer value > 0, you can disable the
24	* control buttons:
25	* <p>
26	* <init-param><param-name>readonly</param-name><param-value>1</param-value></init-param>
27	* <!-- <init-param><param-name>readonly</param-name><param-value>1</param-value></init-param> -->
28	*
29	* You could also configure it dynamically from a ContextListener:
30	* ServletRegistration.Dynamic dynconf = sce.getServletContext().addServlet("circuitbreaker", dk.thoerup.circuitbreaker.web.CircuitBreakerServletBase.class );
31	* dynconf.addMapping("/CircuitBreakerServlet");
32	* dynconf.setInitParameter("readonly", "1");
33	*
34	*/
35
36	public class CircuitBreakerServletBase extends javax.servlet.http.HttpServlet {
37
38	private static final long serialVersionUID = 1L;
39
40	private boolean readOnly = false;
41
42
43
44	@Override
45	public void init() throws ServletException {
46	super.init();
47
48	String readOnlyStr = getInitParameter("readonly");
49	if (readOnlyStr != null && readOnlyStr.trim().length() >0) {
50	int readOnlyInt = Integer.parseInt(readOnlyStr.trim());
51	readOnly = (readOnlyInt > 0);
52	}
53	}
54
55	private Command getCommand(String command) throws ServletException {
56	if (command == null \|\| command.equals("list"))
57	return new ListCircuitBreakers();
58
59	if (command.equals("view"))
60	return new ViewCircuitBreaker(readOnly);
61	if (command.equals("action"))
62	return new ActionCommand(readOnly);
63	if (command.equals("log"))
64	return new LogViewCommand();
65
66	throw new ServletException("No such command:" + command);
67	}
68
69	@Override
70	public void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
71	Command cmd = getCommand( req.getParameter("command"));
72
73	String response = cmd.execute(req,resp);
74
75	resp.setDateHeader("Expires", 0);
76	resp.setHeader("Pragma", "no-cache");
77	resp.setHeader("Cache-Control", "no-cache");
78	resp.setContentType("text/html");
79
80	resp.getWriter().print(response);
81	}
82
83	@Override
84	protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
85	doGet(req, resp);
86	}
87
88	}