1 files changed, 14 insertions, 22 deletions

diff --git a/subprojects/language-web/src/main/java/tools/refinery/language/web/xtext/server/push/PushWebDocument.java b/subprojects/language-web/src/main/java/tools/refinery/language/web/xtext/server/push/PushWebDocument.java
index 56fd12c9..dfbd4878 100644
--- a/subprojects/language-web/src/main/java/tools/refinery/language/web/xtext/server/push/PushWebDocument.java
+++ b/subprojects/language-web/src/main/java/tools/refinery/language/web/xtext/server/push/PushWebDocument.java
@@ -5,11 +5,7 @@
  */
 package tools.refinery.language.web.xtext.server.push;
 
-import java.util.ArrayList;
-import java.util.HashMap;
-import java.util.List;
-import java.util.Map;
-
+import com.google.common.collect.ImmutableList;
 import org.eclipse.xtext.util.CancelIndicator;
 import org.eclipse.xtext.web.server.IServiceResult;
 import org.eclipse.xtext.web.server.model.AbstractCachedService;
@@ -17,11 +13,13 @@ import org.eclipse.xtext.web.server.model.DocumentSynchronizer;
 import org.eclipse.xtext.web.server.model.XtextWebDocument;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
-
-import com.google.common.collect.ImmutableList;
-
 import tools.refinery.language.web.xtext.server.ResponseHandlerException;
 
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
 public class PushWebDocument extends XtextWebDocument {
         private static final Logger LOG = LoggerFactory.getLogger(PushWebDocument.class);
 
@@ -36,37 +34,31 @@ public class PushWebDocument extends XtextWebDocument {
                 }
         }
 
-        public boolean addPrecomputationListener(PrecomputationListener listener) {
+        public void addPrecomputationListener(PrecomputationListener listener) {
                 synchronized (precomputationListeners) {
                         if (precomputationListeners.contains(listener)) {
-                                return false;
+                                return;
                         }
                         precomputationListeners.add(listener);
                         listener.onSubscribeToPrecomputationEvents(getResourceId(), this);
-                        return true;
                 }
         }
 
-        public boolean removePrecomputationListener(PrecomputationListener listener) {
+        public void removePrecomputationListener(PrecomputationListener listener) {
                 synchronized (precomputationListeners) {
-                        return precomputationListeners.remove(listener);
+                        precomputationListeners.remove(listener);
                 }
         }
 
         public <T extends IServiceResult> void precomputeServiceResult(AbstractCachedService<T> service, String serviceName,
                         CancelIndicator cancelIndicator, boolean logCacheMiss) {
-                var result = getCachedServiceResult(service, cancelIndicator, logCacheMiss);
-                if (result == null) {
-                        LOG.error("{} service returned null result", serviceName);
-                        return;
-                }
                 var serviceClass = service.getClass();
                 var previousResult = precomputedServices.get(serviceClass);
-                if (previousResult != null && previousResult.equals(result)) {
-                        return;
-                }
+                var result = getCachedServiceResult(service, cancelIndicator, logCacheMiss);
                 precomputedServices.put(serviceClass, result);
-                notifyPrecomputationListeners(serviceName, result);
+                if (result != null && !result.equals(previousResult)) {
+                        notifyPrecomputationListeners(serviceName, result);
+                }
         }
 
         private <T extends IServiceResult> void notifyPrecomputationListeners(String serviceName, T result) {