1 files changed, 35 insertions, 10 deletions

diff --git a/module/ri-engine/src/main/java/io/trygvis/rules/engine/Engine.java b/module/ri-engine/src/main/java/io/trygvis/rules/engine/Engine.java
index ef6b4b1..46a3302 100644
--- a/module/ri-engine/src/main/java/io/trygvis/rules/engine/Engine.java
+++ b/module/ri-engine/src/main/java/io/trygvis/rules/engine/Engine.java
@@ -1,6 +1,7 @@
 package io.trygvis.rules.engine;
 
 import org.drools.core.audit.WorkingMemoryConsoleLogger;
+import org.drools.core.base.MapGlobalResolver;
 import org.drools.reflective.classloader.ProjectClassLoader;
 import org.kie.api.KieServices;
 import org.kie.api.event.rule.AgendaEventListener;
@@ -11,6 +12,7 @@ import org.kie.api.runtime.KieSession;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
+import javax.annotation.Nullable;
 import java.io.Closeable;
 import java.io.File;
 import java.io.FileNotFoundException;
@@ -24,20 +26,25 @@ import java.util.List;
 import static io.trygvis.rules.engine.TemplateEngine.TemplateLoader;
 
 public class Engine implements Closeable {
+    @SuppressWarnings("FieldCanBeLocal")
     private final Logger logger = LoggerFactory.getLogger(getClass());
 
+    public final String name;
+    @Nullable
+    public final File output;
     public final DbIo io;
     public final KieSession session;
 
-    public Engine(String name, File[] databases, File output, String[] agendaGroups, File[] modules) throws IOException {
+    public Engine(String name, File[] databases, @Nullable File output, String[] agendaGroups, File[] modules)
+            throws IOException {
+        this.name = name;
+        this.output = output;
+
         logger.info("Getting KieServices");
 
         var services = KieServices.Factory.get();
 
-        logger.info("services = {}", services);
-
         var kieRepository = services.getRepository();
-        logger.info("kieRepository.getDefaultReleaseId() = {}", kieRepository.getDefaultReleaseId());
 
         KieContainer container;
         TemplateLoader templateLoader;
@@ -85,12 +92,7 @@ public class Engine implements Closeable {
         session.addEventListener((AgendaEventListener) l);
         session.addEventListener((RuleRuntimeEventListener) l);
 
-        var te = session.getGlobals().get("te");
-        try {
-            session.setGlobal("te", new JinjavaTemplateEngine(templateLoader, output));
-        } catch (java.lang.RuntimeException ignore) {
-            // This happens if the rules doesn't need the template engine.
-        }
+        session.getGlobals().setDelegate(new EngineGlobalResolver(templateLoader));
 
         logger.info("Loading data");
         io = new DbIo(container, kieBase);
@@ -146,4 +148,27 @@ public class Engine implements Closeable {
             }
         }
     }
+
+    private class EngineGlobalResolver extends MapGlobalResolver {
+        private final TemplateLoader templateLoader;
+
+        public EngineGlobalResolver() {
+            templateLoader = null;
+        }
+
+        public EngineGlobalResolver(TemplateLoader templateLoader) {
+            this.templateLoader = templateLoader;
+        }
+
+        @Override
+        public Object resolveGlobal(String identifier) {
+            if ("te".equals(identifier)) {
+                if (output == null) {
+                    throw new IllegalArgumentException("An instance of the TemplateEngine is required, but this job is not configured with a output directory.");
+                }
+                return new JinjavaTemplateEngine(templateLoader, output);
+            }
+            return super.resolveGlobal(identifier);
+        }
+    }
 }