Is there any API in drools to create the drl files dynamically by just passing values?

Question

I know how to create DRL files inside KIE workbench by using all the methods. But what my problem is without using the KIE workbench, can we create the .drl fil

Answer 1

You can use Drools Fluent API. Try below sample code :

package com.sample;

import java.io.BufferedWriter;
import java.io.File;
import java.io.FileWriter;

import org.drools.lang.DrlDumper;
import org.drools.lang.api.DescrFactory;
import org.drools.lang.descr.PackageDescr;

@SuppressWarnings("restriction")
public class Drl_Creator {
    public static void main(String str[]){
        PackageDescr pkg = DescrFactory.newPackage()
                   .name("org.drools.example")
                   .newRule().name("Xyz")
                       .attribute("ruleflow-grou","bla")
                   .lhs()
                       .and()
                           .pattern("Foo").id( "$foo", false ).constraint("bar==baz").constraint("x>y").end()
                           .not().pattern("Bar").constraint("a+b==c").end().end()
                       .end()
                   .end()
                   .rhs( "System.out.println();" ).end()
                   .getDescr();
        DrlDumper dumper=new DrlDumper();
        String drl=dumper.dump(pkg);
        System.out.print(drl);
        try{
            // create new file
            File file = new File("src/main/rules/test.drl");
            file.createNewFile();
            FileWriter fw = new FileWriter(file.getAbsoluteFile());
            BufferedWriter bw = new BufferedWriter(fw);
            bw.write(drl);
            // close connection
            bw.close();
            System.out.println("File Created Successfully");
         }catch(Exception e){
             System.out.println(e);
         }
    }
}