source: trunk/gsdl3/packages/gsdl-as/src/org/greenstone/gsdlas/AlertingService.java@ 8630

/*
 * Created on Nov 22, 2004
 * Copyright (C) Andrea Schweer, 2004
 *
 * This file is part of the Greenstone Alerting Service.
 * Refer to the COPYING file in the base directory of this package
 * for licensing information.
 */
package org.greenstone.gsdlas;

import java.io.IOException;
import java.lang.reflect.Method;
import java.net.MalformedURLException;
import java.net.URL;
import java.util.*;

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

import org.apache.velocity.Template;
import org.apache.velocity.context.Context;
import org.apache.velocity.exception.ParseErrorException;
import org.apache.velocity.exception.ResourceNotFoundException;
import org.apache.velocity.servlet.VelocityServlet;
import org.greenstone.gsdlas.profiles.*;

/**
 * @author schweer
 *
 * TODO To change the template for this generated type comment go to
 * Window - Preferences - Java - Code Style - Code Templates
 */
public class AlertingService extends VelocityServlet {
    
    public static final Set actions = new TreeSet();
    static {
        actions.add("subscribe");
        actions.add("showFeed");
        actions.add("listSubscriptions"); // TODO remove (just for debugging)
    }
    
    protected Template handleRequest(HttpServletRequest req,
            HttpServletResponse res, Context context) {
        
        String action = req.getParameter("action");
        
        if (action == null || !actions.contains(action)) {
            context.put("title", "Unknown action");
            context.put("message", "I don't know how to " + action);
            context.put("details", "The only actions I know are " + actions);
            try {
                return getTemplate("error.vm");
            } catch (ResourceNotFoundException e1) {
                // TODO Auto-generated catch block
                e1.printStackTrace();
            } catch (ParseErrorException e1) {
                // TODO Auto-generated catch block
                e1.printStackTrace();
            } catch (Exception e1) {
                // TODO Auto-generated catch block
                e1.printStackTrace();
            }
            return null;
        }
        

        Map args = req.getParameterMap();
        args = normalise(args);
        
        String templateString = "";
        
        try {
            Method method = AlertingService.class.getDeclaredMethod(action, new Class[] {Map.class, Context.class});
            templateString = (String) method.invoke(this, new Object[] {args, context});
        } catch (Exception e) {
            templateString = "error.vm";
            context.put("title", "Error");
            context.put("message", "A general error has occured, I couldn't do what you told me to do.");
            context.put("details", e.getMessage() + " (" + e.getClass().getName() + "), action is " + action);
        }
        
        Template template = null;
        try {
            template = getTemplate(templateString);
        } catch (Exception e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
            try {
                error(req, res, e);
            } catch (ServletException e2) {
                // TODO Auto-generated catch block
                e2.printStackTrace();
            } catch (IOException e2) {
                // TODO Auto-generated catch block
                e2.printStackTrace();
            }
        }
        return template;
    }
    
    /**
     * @param arguments
     * @param context
     * @return the Velocity template to use
     */
    public String subscribe(Map arguments, Context context) {
        context.put("title", "Adding Subscription");
        if (arguments.size() == 0) {
            context.put("message", "Empty subscription, not added");
            context.put("details", "A subscription has to define at least one predicate.");
            return "error.vm";
        }
        try {
            // TODO pass user information to profile store
            Subscription sub = new Subscription(arguments);
            // TODO this should probably be somewhere else
            for (Iterator iter = sub.getPredicates().iterator(); iter.hasNext();) {
                Predicate predicate = (Predicate) iter.next();
                if (predicate != null) {
                    predicate.addSubscription(sub);
                }
            }
            ProfileStore.getInstance().addSubscription(sub);
        } catch (ParseException e) {
            context.put("message", "Eror in subscription creation, not added");
            context.put("details", e.getMessage());
            return "error.vm";
        }
        context.put("message", "Subscription added successfully");
        return "general.vm";
    }
    
    public String showFeed(Map arguments, Context context) {
        context.put("list", ""/* TODO pass subscription list */);
        return "feed.vm";
    }
    
    public String listSubscriptions(Map arguments, Context context) {
        context.put("title", "List of Subscriptions");
        context.put("list", ProfileStore.getInstance().getAllSubscriptions());
        return "list.vm";
    }
    
    public void receive(Map event) {
        GreenstoneCommunicator gsComm = null;
        try {
            gsComm = new GreenstoneCommunicator(new URL((String) event.get("host_url")));
        } catch (MalformedURLException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (Exception e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        Set matchedSubscriptions = ProfileStore.getInstance().filter(event, gsComm);
        // TODO do something with the matched subscriptions
    }

    /**
     * @param args
     */
    private Map normalise(Map args) {
        Map result = new TreeMap();
        for (Iterator iter = args.keySet().iterator(); iter.hasNext();) {
            String key = (String) iter.next();
            if (!key.equals("action")) {
                String firstValue = ((String[]) args.get(key))[0];
                result.put(key, firstValue);
            }
        }
        return result;
    }
}