Issue in Date handling for JSON Object - json

Question

[enter image description here][1]I am facing some issue in Drools I want to pass date as a date type but currently we don't have any method in JSONObject to handle dates .My JSONObject looks like this.
{"id":600,"city":"Gotham","age":25,"startDate":"29-DEC-2017","endDate":"2014-08-31"}
My Drool condition looks like this.
package com.rules
import org.drools.core.spi.KnowledgeHelper;
import org.json.JSONObject;
rule "ComplexRule1"
salience 100
dialect "mvel"
date-effective "16-Jan-2018 00:00"
no-loop
when
$cdr : JSONObject( $cdr.optString("startDate") >= '28-Dec-2017')
then
$cdr.put("Action_1" , new JSONObject().put("actionName","Complex_Rule1_Action1").put("actionTypeName","SEND OFFER").put("channelName","SMS").put("messageTemplateName","SMSTemplate").put("#timestamp",(new java.text.SimpleDateFormat("yyyy/MM/dd HH:mm:ss")).format(new java.util.Date())).put("ruleFileName","ComplexRule1.drl").put("ruleName","ComplexRule1"));
end
I am currently using .optString Because we dont have any methods like optString/optInt/optBoolean for date. So how can I handle date in Drools?
Any help will be appreciated.
Regards Puneet
My new DRL looks like this :
package com.rules
import com.aravind.drools.SuperJSONObject;
import org.drools.core.spi.KnowledgeHelper;
import org.json.JSONObject;
rule "Convert to SuperJSONObject"
when
$cdr: JSONObject()
then
insert(new SuperJSONObject($cdr));
end
rule "ComplexRule1"
salience 100
dialect "mvel"
date-effective "16-Jan-2018 00:00"
no-loop
when
$cdr : SuperJSONObject( $cdr.getAsDate("startDate") == '28-Dec-2017')
then
$cdr.getObject().put("Action_1" , new JSONObject().put("actionName","Complex_Rule1_Action1").put("actionTypeName","SEND OFFER").put("channelName","SMS").put("messageTemplateName","SMSTemplate").put("#timestamp",(new java.text.SimpleDateFormat("yyyy/MM/dd HH:mm:ss")).format(new java.util.Date())).put("ruleFileName","ComplexRule1.drl").put("ruleName","ComplexRule1"));
end
Class look like this :
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Date;
import org.json.*;
public class SuperJSONObject {
public final JSONObject obj;
SimpleDateFormat sdfmt2= new SimpleDateFormat("yyyy/MM/dd");
public SuperJSONObject(JSONObject obj){
this.obj = obj;
}
public Date getAsDate(String field) throws ParseException{
return sdfmt2.parse(this.obj.optString(field));
}
public JSONObject getObject(){
return this.obj;
}
}
Another Class is like this
import java.io.File
import java.io.FileReader
import org.drools.KnowledgeBase
import org.drools.KnowledgeBaseFactory
import org.drools.builder.KnowledgeBuilder
import org.drools.builder.KnowledgeBuilderFactory
import org.drools.builder.ResourceType
import org.drools.io.ResourceFactory
import org.drools.runtime.StatefulKnowledgeSession
import org.json.JSONObject
object RunStandAloneDrools {
def main(args: Array[String]): Unit = {
var jsonObjectArray: Array[JSONObject] = new Array(1)
jsonObjectArray(0) = new JSONObject("{\"id\":600,\"city\":\"Gotham\",\"age\":25,\"startDate\":\"28-Dec-2017\",\"endDate\":\"2014-08-01\"}")
var file: String = "/home/puneet/Downloads/ComplexRule1.drl"
var kbuilder: KnowledgeBuilder = KnowledgeBuilderFactory.newKnowledgeBuilder()
kbuilder.add(ResourceFactory.newReaderResource(new FileReader(new File(file))), ResourceType.DRL)
println("Errors? " + kbuilder.getErrors.size())
var iter = kbuilder.getErrors.iterator()
while(iter.hasNext()){
println(iter.next().getMessage)
}
var kbase: KnowledgeBase = KnowledgeBaseFactory.newKnowledgeBase()
kbase.addKnowledgePackages(kbuilder.getKnowledgePackages)
var session: StatefulKnowledgeSession = kbase.newStatefulKnowledgeSession()
callRulesEngine(jsonObjectArray,session)
println("Done")
}
def callRulesEngine(data: Array[JSONObject], knowledgeSession: StatefulKnowledgeSession): Unit = {
data.map ( x => callRulesEngine(x,knowledgeSession) )
}
def callRulesEngine(data: JSONObject, knowledgeSession: StatefulKnowledgeSession): Unit = {
try {
println("Input data " + data.toString())
knowledgeSession.insert(data)
knowledgeSession.fireAllRules()
println("Facts details " + knowledgeSession.getFactCount)
println("Enriched data " + data.toString())
} catch {
case (e: Exception) => println("Exception", e);
}
}
`
Output is not coming as per expectations

Answer 1

There are multiple ways to deal with this, but the fundamental thing is for you to understand that this is NOT a Drools issue at all. Your question is more on how do get a Date from a JSONObject.
One way this could be achieved is by using a function in Drools to make the conversion.
But I don't like functions, so I'll give you another, more elaborated, way to deal with this situation (and many others where a type conversion is required).
The idea is to create a wrapper class for your JSONObject- a SuperJSONObject- that will expose all the functionality you need. For the implementation of this class I will be using composition, but you can use inheritance (or a proxy) if you want.
public class SuperJSONObject {
public final JSONObject obj;
public SuperJSONObject(JSONObject obj){
this.obj = obj;
}
//expose all the methods from JSONObject you want/need
public Date getAsDate(String field){
return someDateParser.parse(this.obj.optString(field));
}
public JSONObject getObject(){
return this.obj;
}
}
So now we have a getAsDate() method that we can use in our rules. But we first need to convert a JSONObject into a SuperJSONObject before we can even use that method. You can do this in multiple ways and places. I'll be showing how to do it in DRL.
rule "Convert to SuperJSONObject"
when
$jo: JSONObject() //you may want to filter which objects are converted by adding constraints to this pattern
then
insert(new SuperJSONObject($jo));
end
And now we are good to go. We can now write a rule using this new class as follows:
rule "ComplexRule1"
salience 100
dialect "mvel"
date-effective "16-Jan-2018 00:00"
no-loop
when
$cdr : SuperJSONObject( getAsDate("startDate") >= '28-Dec-2017')
then
$cdr.getObject().put("Action_1" , ...);
end
After I have written all this code, I might reconsider the option of a simple function in DRL... :P
Hope it helps,