[rules-users] question about updating main memory
Jaroslaw Kijanowski
kijanowski at gmail.com
Mon Jul 7 12:41:50 EDT 2008
What I'm missing is an import statement in your drl file (import
tests.Test.ClassP;).
Everything else looks correct and should give the expected results
(ResultSize = 5).
Cheers,
Jarek
Senlin Liang wrote:
> Hi all,
>
> I am trying to insert some object, querying them and the retract them.
> My question, when I query the inserted objects using defined "query",
> it return 0 objects. But when I iterate over all objects in WM, the
> objects are returned.
>
> Any information is appreciated!
>
> Files:
> ===================test.drl====================
> package tests;
> query "selectQuery"
> p : ClassP()
> end
> ==================end of test.drl================
>
> ==================Test.java====================
> package tests;
>
> import java.io.*;
> import java.io.InputStreamReader;
> import org.drools.RuleBase;
> import org.drools.RuleBaseFactory;
> import org.drools.StatefulSession;
> import org.drools.compiler.PackageBuilder;
> import org.drools.QueryResult;
> import org.drools.QueryResults;
> import org.drools.FactHandle;
> import java.util.Iterator;
>
> public class Test {
> public static void main (String args[]) {
> try {
> Reader source = new
> InputStreamReader(Test.class.getResourceAsStream("../test.drl"));
> final PackageBuilder builder = new PackageBuilder();
> builder.addPackageFromDrl(source);
> if (builder.hasErrors()) {
> System.out.println(builder.getErrors().toString());
> System.exit(0);
> }
> final RuleBase ruleBase = RuleBaseFactory.newRuleBase();
> ruleBase.addPackage(builder.getPackage());
> final StatefulSession session = ruleBase.newStatefulSession();
>
> System.out.println("Inserting objects ...");
> for (int i = 0; i < 5; i ++) {
> session.insert(new ClassP(1, i));
> }
>
> System.out.println("Querying objects ...");
> QueryResults results = session.getQueryResults("selectQuery");
> System.out.println("ResultSize = " + results.size());
> /***************************************************************************************
> Here, it reports results.size() is 0, and there should be
> 5 objects in WM right now. It is
> the place I got the question.
>
> I have no idea whether I am using the "query" correctly.
> Anything wrong?
> ***************************************************************************************/
> for (Iterator it = results.iterator(); it.hasNext(); ) {
> final QueryResult result = (QueryResult) it.next();
> ClassP p = (ClassP) result.get("p");
> System.out.println("p(" + p.getFirst() + ", " + p.getSecond()+")");
> }
>
> System.out.println("Deleting ...");
> for (Iterator it = session.iterateFactHandles(); it.hasNext(); ) {
> FactHandle factHandle = (FactHandle) it.next();
> ClassP p = (ClassP) session.getObject(factHandle);
> System.out.println("p(" + p.getFirst() + ", " + p.getSecond()+")");
> session.retract(factHandle);
> }
> /***************************************************************************************
> Here, it prints out: it is deleting p(1, 1), ... p(1, 5).
> It verifies that there are the 5 objects inserted.
> ***************************************************************************************/
>
> session.dispose();
> } catch (Exception e) {
> System.out.println(e);
> System.exit(0);
> }
> }
>
> public static class ClassP {
> private int first;
> private int second;
> public ClassP() {}
> public ClassP(int firstIn, int secondIn) {
> this.first = firstIn;
> this.second = secondIn;
> }
> public int getFirst() {
> return this.first;
> }
> public int getSecond() {
> return this.second;
> }
> }
> }
> ========================end of Test.java=====================
>
> Thanks a lot,
>
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