X-Git-Url: https://gerrit.simantics.org/r/gitweb?a=blobdiff_plain;f=bundles%2Forg.simantics.db.layer0%2Fsrc%2Forg%2Fsimantics%2Fdb%2Flayer0%2Fvariable%2FStandardVariableBuilder.java;h=992e3e6990fba165c0fd6c6ca901a479b4521730;hb=035118aa5f35c9e5acd1f34d22065055dfdee486;hp=b94c6ce7424639931bf37e192d05b8b613c8dc09;hpb=969bd23cab98a79ca9101af33334000879fb60c5;p=simantics%2Fplatform.git

diff --git a/bundles/org.simantics.db.layer0/src/org/simantics/db/layer0/variable/StandardVariableBuilder.java b/bundles/org.simantics.db.layer0/src/org/simantics/db/layer0/variable/StandardVariableBuilder.java
index b94c6ce74..992e3e699 100644
--- a/bundles/org.simantics.db.layer0/src/org/simantics/db/layer0/variable/StandardVariableBuilder.java
+++ b/bundles/org.simantics.db.layer0/src/org/simantics/db/layer0/variable/StandardVariableBuilder.java
@@ -1,19 +1,30 @@
-package org.simantics.db.layer0.variable;
-
-import org.simantics.db.ReadGraph;
-import org.simantics.db.Resource;
-import org.simantics.db.exception.DatabaseException;
-
-public class StandardVariableBuilder<Node> implements VariableBuilder<Node> {
-
-	@Override
-	public Variable buildChild(ReadGraph graph, Variable parent, VariableNode<Node> node, Resource child) {
-		return new StandardGraphChildVariable(parent, node, child);
-	}
-
-	@Override
-	public Variable buildProperty(ReadGraph graph, Variable parent, VariableNode<Node> node, Resource subject, Resource predicate) throws DatabaseException {
-		return new StandardGraphPropertyVariable(graph, parent, node, subject, predicate);
-	}
-
-}
+package org.simantics.db.layer0.variable;
+
+import org.simantics.db.ReadGraph;
+import org.simantics.db.Resource;
+import org.simantics.db.exception.DatabaseException;
+
+public class StandardVariableBuilder<Node> implements VariableBuilder<Node> {
+
+    private static StandardVariableBuilder<?> INSTANCE = null;
+
+    private StandardVariableBuilder() {}
+
+    public static synchronized StandardVariableBuilder<?> get() {
+        if(INSTANCE == null) {
+            INSTANCE = new StandardVariableBuilder<>();
+        }
+        return INSTANCE;
+    }
+
+    @Override
+    public Variable buildChild(ReadGraph graph, Variable parent, VariableNode<Node> node, Resource child) {
+        return new StandardGraphChildVariable(parent, node, child);
+    }
+
+    @Override
+    public Variable buildProperty(ReadGraph graph, Variable parent, VariableNode<Node> node, Resource subject, Resource predicate) throws DatabaseException {
+        return new StandardGraphPropertyVariable(graph, parent, node, subject, predicate);
+    }
+
+}