11:08 a.m.
1) You are completely circumventing the need for rules by putting business logic in the
functions. If you want to do this, there's no reason to use rules at all.
2) To do it properly insert the VehicleLocation objects into working memory and use the
"accumulate" keyword to determine if there are three of them that fit your
criteria. See section "4.8.2.10. Conditional Element accumulate" here:
https://hudson.jboss.org/hudson/job/drools/lastSuccessfulBuild/artifact/t...
--- On Fri, 7/24/09, PriyaSha <nash.8103(a)gmail.com> wrote:
From: PriyaSha <nash.8103(a)gmail.com>
Subject: [rules-users] Using eval in LHS
To: rules-users(a)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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