[rules-users] Using eval in LHS
nash.8103 at gmail.com
nash.8103 at gmail.com
Fri Jul 24 15:16:58 EDT 2009
Thanks Greg.....
The reason I chose HashMap is that an accident is said to occur if and only if more than 1 vehicle contains four consecutive position report as same. So in my hashmap key is vehicle id and value is the no. Of times same position report received... Can you suggest me a way to
1. Collect all vehicles stopped at some point and the occurance of that event is reported more than thrice
2. Report accident if there are more than one vehicle found in step 1
---Priya
-original message-
Subject: Re: [rules-users] Using eval in LHS
From: Greg Barton <greg_barton at yahoo.com>
Date: 24/07/2009 10:36 pm
Try this:
rule "Create Collision Location"
salience 90
no-loop true
when
vehLoc : VehicleLocation()
not CollisionLocation(xway == vehLoc.xway, pos ==
vehLoc.pos, dir == vehLoc.dir, lane == vehLoc.lane)
then
CollisionLocation collisionLoc = new CollisionLocation(vehLoc.getXway(),
vehLoc.getPos(), vehLoc.getDir(), vehLoc.getLane());
insert(collisionLoc);
end
rule "Collect Collided Vehicles"
salience 90
no-loop true
when
vehLoc : VehicleLocation()
$collisionLoc : CollisionLocation(xway == vehLoc.xway, pos ==
vehLoc.pos, dir == vehLoc.dir, lane == vehLoc.lane)
then
collisionLoc.getVehicleLocations().add(vehLoc);
update(collisionLoc);
end
And now, the rule that detects more than three coinciding vehicle locations is simple:
rule "Detect Too Many"
when
CollisionLocation(vehicleLocations.size > 2)
then
...foo...
end
And, if you want to make the execution a bit more efficient, put a reference in VehicleLocation to it's associated CollisionLocation. That way you can have "vehLoc : VehicleLocation(collisionLocation == null)" to reduce partial matches.
--- On Fri, 7/24/09, PriyaSha <nash.8103 at gmail.com> wrote:
> From: PriyaSha <nash.8103 at gmail.com>
> Subject: [rules-users] Using eval in LHS
> To: rules-users at lists.jboss.org
> Date: Friday, July 24, 2009, 10:45 AM
>
> Input:
> 0,0,107,32,0,0,0,10,53320,-1,-1,-1,-1,-1,-1
> 0,0,107,32,0,0,0,10,53320,-1,-1,-1,-1,-1,-1
> 0,0,107,32,0,0,0,10,53320,-1,-1,-1,-1,-1,-1
> 0,0,107,32,0,0,0,10,53320,-1,-1,-1,-1,-1,-1
> 0,0,109,20,0,0,0,19,100644,-1,-1,-1,-1,-1,-1
> 0,0,109,20,0,0,0,19,100644,-1,-1,-1,-1,-1,-1
> 0,0,106,28,0,0,0,26,137745,-1,-1,-1,-1,-1,-1
> 0,0,108,32,0,0,0,67,354281,-1,-1,-1,-1,-1,-1
> 0,0,105,30,0,0,1,94,501089,-1,-1,-1,-1,-1,-1
>
> Problem:
>
> Should find vehicles with same data (if it occurs more than
> thrice).
>
> Though eval in rule 'Detect Accident' results in true,
> consequence is not
> fired.
>
> Output:
>
> Added
> Not Found -- 107---2
> test---2----107
> Not Found -- 107---3
> test---3----107
> Not Found -- 107---4
> test---4----107
> no of veh : 1
> no of veh : 1
> no of veh : 1
> Not Found -- 109---5
> test---1----109
> Not Found -- 109---6
> test---2----109
> Not Found -- 106---7
>
> Please find the DRL below.
>
>
> package com.hp.hpl.CHAOS.LR;
>
> # importing classes
> import java.lang.Integer;
>
> import java.util.ArrayList;
> import java.util.HashMap;
> import java.util.Iterator;
>
> import com.hp.hpl.CHAOS.Rules.VehicleLocation;
>
> global java.lang.String output
>
> declare VehicleLocation
> @role ( event )
> @expires ( 1m )
> end
>
> declare Statistics
> smashedcars : ArrayList
> stopped_cars : ArrayList
> accidents : ArrayList
> collided_at : HashMap
> end
>
> rule "Setup statistics"
> salience 110
> no-loop true
> when
> not( Statistics( ) )
> vehLoc : VehicleLocation()
> then
> Statistics s = new Statistics();
> s.setSmashedcars (new ArrayList());
> s.setStopped_cars (new ArrayList());
> s.getStopped_cars().add(vehLoc);
> s.setCollided_at(new HashMap());
> insert( s );
>
> System.out.println("Added");
> end
>
> rule "Add to stopped cars"
> salience 100
> no-loop true
> when
> vehLoc : VehicleLocation()
> $stat : Statistics ()
> ((not( VehicleLocation(vid ==
> vehLoc.vid) from $stat.getSmashedcars())))
> then
> modify($stat) {
>
> getStopped_cars().add(vehLoc);
> }
> System.out.println("Not Found -- " +
> vehLoc.getVid() + "---" +
> $stat.getStopped_cars().size());
> end
>
>
> rule "Identify Collided Vehicles"
> salience 90
> no-loop true
> when
> vehLoc : VehicleLocation()
> $stat : Statistics ()
> $allStoppedcars : ArrayList( size > 0
> )
> from
> collect ( VehicleLocation(xway == vehLoc.xway, pos ==
> vehLoc.pos, dir == vehLoc.dir, lane == vehLoc.lane) from
> $stat.stopped_cars)
> then
> System.out.println("test" + "---" +
> $allStoppedcars.size() + "----" +
> vehLoc.getVid());
>
> modify($stat) {
>
> setCollided_at(collided_at($allStoppedcars,
> vehLoc.getXway(),
> vehLoc.getPos(), vehLoc.getDir(), vehLoc.getLane()));
> }
> retract (vehLoc);
> end
>
> rule "Detect Accident"
> salience 80
> no-loop true
> when
> vehLoc : VehicleLocation()
> $stat : Statistics ()
>
> eval(collision_occured($stat.getCollided_at()))
> then
> System.out.println("Detect Accident");
> end
>
> function HashMap collided_at(ArrayList stopped_cars, int x,
> int pos, int
> dir, int lane) {
> HashMap collided_at = new HashMap();
> for (Iterator iterator =
> stopped_cars.iterator(); iterator.hasNext(); )
> {
> VehicleLocation vehLoc =
> (VehicleLocation) iterator.next();
> if (vehLoc.getXway() == x
> &&
> vehLoc.getPos() == pos
> &&
> vehLoc.getDir() == dir
> &&
> vehLoc.getLane() == lane) {
>
> int key =
> vehLoc.getVid();
> if
> (!collided_at.containsKey(key)) {
>
> collided_at.put (key, new Integer(1));
>
> continue;
> }
> collided_at.put
> (key,
> ((Integer)collided_at.get(key)).intValue()+1);
> }
> }
> return collided_at;
> }
>
> function boolean collision_occured(HashMap
> collided_vehicles) {
> java.util.Set entries =
> collided_vehicles.entrySet();
> int noOfCollidedVehicles = 0;
> java.util.Iterator iterator =
> entries.iterator();
>
> while ( iterator.hasNext() ) {
> java.util.Map.Entry object =
> (java.util.Map.Entry) iterator.next();
> if ((Integer)object.getValue()
> > 3) {
>
> noOfCollidedVehicles += 1;
> }
> }
>
> if (noOfCollidedVehicles > 0) {
> System.out.println("no of veh :
> " + noOfCollidedVehicles);
> return true;
> }
> return false;
> }
>
> Please let me know what should I correct here.
> --
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> Sent from the drools - user mailing list archive at
> Nabble.com.
>
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