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package dk.thoerup.circuitbreaker.web;
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import java.io.IOException;
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import javax.servlet.ServletException;
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import javax.servlet.http.*;
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/**
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* This is a web interface for viewing and controlling the CircuitBreakers currently registered in CircuitBreakerManager
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* <p>
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* To use this servlet in you .war module just create a simple servlet that extends this class (instead of HttpServlet)
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* The new custom servlet doesn't need to implement any of the standard servlet methods - its all done in this implementation.
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*
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* <p>
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* Example:
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* <pre>
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* public class CircuitBreakerServlet extends CircuitBreakerServletBase {
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* private static final long serialVersionUID = 1L;
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* }
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* </pre>
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*
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* If you add a servlet init pameter to your deployment descriptor with the name 'readonly' and a integer value > 0, you can disable the
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* control buttons:
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* <p>
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* <init-param><param-name>readonly</param-name><param-value>1</param-value></init-param>
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* <!-- <init-param><param-name>readonly</param-name><param-value>1</param-value></init-param> -->
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*
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*/
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public class CircuitBreakerServletBase extends javax.servlet.http.HttpServlet {
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private static final long serialVersionUID = 1L;
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private boolean readOnly = false;
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@Override
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public void init() throws ServletException {
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super.init();
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String readOnlyStr = getInitParameter("readonly");
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if (readOnlyStr != null && readOnlyStr.trim().length() >0) {
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int readOnlyInt = Integer.parseInt(readOnlyStr.trim());
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readOnly = (readOnlyInt > 0);
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}
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}
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private Command getCommand(String command) throws ServletException {
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if (command == null || command.equals("list"))
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return new ListCircuitBreakers();
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if (command.equals("view"))
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return new ViewCircuitBreaker(readOnly);
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if (command.equals("action"))
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return new ActionCommand(readOnly);
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throw new ServletException("No such command:" + command);
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}
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@Override
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public void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
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Command cmd = getCommand( req.getParameter("command"));
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String response = cmd.execute(req,resp);
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resp.setDateHeader("Expires", 0);
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resp.setHeader("Pragma", "no-cache");
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resp.setHeader("Cache-Control", "no-cache");
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resp.setContentType("text/html");
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resp.getWriter().print(response);
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}
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@Override
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protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
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doGet(req, resp);
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}
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}
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