org.sc.probro.servlets.RequestStateServlet.java Source code

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Here is the source code for org.sc.probro.servlets.RequestStateServlet.java

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/*
   Copyright 2010 Massachusetts General Hospital
    
   Licensed under the Apache License, Version 2.0 (the "License");
   you may not use this file except in compliance with the License.
   You may obtain a copy of the License at
    
   http://www.apache.org/licenses/LICENSE-2.0
    
   Unless required by applicable law or agreed to in writing, software
   distributed under the License is distributed on an "AS IS" BASIS,
   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   See the License for the specific language governing permissions and
   limitations under the License.
*/
package org.sc.probro.servlets;

import java.util.*;
import java.io.*;

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

import org.eclipse.jetty.util.log.Log;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import org.sc.probro.exceptions.BrokerException;
import org.sc.probro.utils.Numbering;
import org.sc.probro.utils.Pairing;
import org.sc.probro.utils.StateMachine;

public class RequestStateServlet extends SkeletonServlet {

    public static Numbering<String> STATES;
    public static StateMachine MACHINE;

    static {
        STATES = new Numbering<String>("REDUNDANT", "FULFILLED", "PENDING", "INCOMPLETE", "ERROR", "ESCALATE",
                "ACCEPTED", "WITHDRAWN");

        MACHINE = new StateMachine();
        for (int i = 0; i < STATES.size(); i++) {
            MACHINE.addState(STATES.backward(i));
        }

        MACHINE.addTransition("PENDING", "RESPOND-INCOMPLETE", "INCOMPLETE");
        MACHINE.addTransition("PENDING", "RESPOND-ERROR", "ERROR");
        MACHINE.addTransition("PENDING", "RESPOND-ESCALATE", "ESCALATE");
        MACHINE.addTransition("PENDING", "RESPOND-FULFILLED", "FULFILLED");
        MACHINE.addTransition("PENDING", "RESPOND-REDUNDANT", "REDUNDANT");
        MACHINE.addTransition("PENDING", "UPDATE-WITHDRAWN", "WITHDRAWN");

        MACHINE.addTransition("INCOMPLETE", "UPDATE-PENDING", "PENDING");
        MACHINE.addTransition("INCOMPLETE", "UPDATE-WITHDRAWN", "WITHDRAWN");
        MACHINE.addTransition("INCOMPLETE", "UPDATE-ESCALATE", "ESCALATE");

        MACHINE.addTransition("ERROR", "UPDATE-PENDING", "PENDING");
        MACHINE.addTransition("ERROR", "UPDATE-WITHDRAWN", "WITHDRAWN");
        MACHINE.addTransition("ERROR", "UPDATE-ESCALATE", "ESCALATE");

        MACHINE.addTransition("ESCALATE", "RESPOND-INCOMPLETE", "INCOMPLETE");
        MACHINE.addTransition("ESCALATE", "RESPOND-ERROR", "ERROR");
        MACHINE.addTransition("ESCALATE", "RESPOND-REDUNDANT", "REDUNDANT");
        MACHINE.addTransition("ESCALATE", "RESPOND-FUFLFILLED", "FULFILLED");
        MACHINE.addTransition("ESCALATE", "UPDATE-WITHDRAWN", "WITHDRAWN");

        MACHINE.addTransition("FULFILLED", "JUDGE-REJECT", "PENDING");
        MACHINE.addTransition("FULFILLED", "JUDGE-ACCEPT", "ACCEPTED");

        MACHINE.addTransition("REDUNDANT", "JUDGE-REJECT", "PENDING");
        MACHINE.addTransition("REDUNDANT", "JUDGE-ACCEPT", "ACCEPTED");
    }

    public static Set<Integer> legalTransitions(Integer fidx) {
        String from = fidx != null ? STATES.backward(fidx) : null;
        Set<Integer> legal = new TreeSet<Integer>();
        for (Integer k = 0; k < MACHINE.size(); k++) {
            String to = STATES.backward(k);
            if (from == null || MACHINE.isReachable(from, to)) {
                legal.add(k);
            }
        }
        return legal;
    }

    protected void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        try {

            String format = getOptionalParam(request, "format", String.class);
            if (format == null) {
                format = "html";
            }

            Log.info(String.format("RequestStateServlet: format=%s", format));

            Integer fromIdx = getOptionalParam(request, "from", Integer.class);
            String from = fromIdx != null ? STATES.backward(fromIdx) : null;

            Log.info(String.format("RequestStateServlet: from=%s", String.valueOf(from)));

            if (format.equals("html")) {

                response.setStatus(HttpServletResponse.SC_OK);
                response.setContentType("text/html");
                PrintWriter writer = response.getWriter();

                writer.println("<table>");

                for (int i = 0; i < STATES.size(); i++) {
                    String to = STATES.backward(i);
                    if (from == null || MACHINE.isReachable(from, to)) {
                        writer.println(String.format("<tr><td>%d</td><td>%s</td></tr>", i, to));
                    }
                }

                writer.println("</table>");

            } else if (format.equals("fieldset")) {

                response.setStatus(HttpServletResponse.SC_OK);
                response.setContentType("text/html");
                PrintWriter writer = response.getWriter();

                writer.println("<fieldset><legend>New Status</legend>");

                for (int i = 0; i < STATES.size(); i++) {
                    String to = STATES.backward(i);
                    if (from == null || MACHINE.isReachable(from, to)) {
                        //writer.println(String.format("<tr><td>%d</td><td>%s</td></tr>", i, to));
                        String field = String
                                .format("<input type=\"radio\" name=\"status\" value=\"%d\">%s</input>", i, to);
                        writer.println(field);
                    }
                }

                writer.println("</fieldset>");

            } else if (format.equals("json")) {

                Log.info("RequestStateServlet: writing JSON response.");

                response.setStatus(HttpServletResponse.SC_OK);
                response.setContentType("application/json");

                JSONObject top = new JSONObject();
                JSONArray array = new JSONArray();
                try {

                    top.put("from", from);
                    top.put("states", array);

                    for (int i = 0; i < STATES.size(); i++) {
                        String to = STATES.backward(i);

                        if (from == null || MACHINE.isReachable(from, to)) {
                            array.put(i);
                        }
                    }
                } catch (JSONException e) {
                    throw new BrokerException(e);
                }

                PrintWriter writer = response.getWriter();
                writer.println(top.toString());

                Log.info(String.format("RequestStateServlet: %s", top.toString()));

            } else {
                throw new BrokerException(HttpServletResponse.SC_BAD_REQUEST, "Unknown 'format' value " + format);
            }

        } catch (BrokerException e) {
            Log.warn(e);
            Log.warn(String.format("RequestStateServlet.doGet() : %s", e.getMessage()));
            handleException(response, e);
        }
    }
}