bundles/org.simantics.db.layer0/src/org/simantics/db/layer0/variable/StandardVariableBuilder.java

   1 package org.simantics.db.layer0.variable;
   2
   3 import org.simantics.db.ReadGraph;
   4 import org.simantics.db.Resource;
   5 import org.simantics.db.exception.DatabaseException;
   6
   7 public class StandardVariableBuilder<Node> implements VariableBuilder<Node> {
   8
   9     private static StandardVariableBuilder<?> INSTANCE = null;
  10
  11     private StandardVariableBuilder() {}
  12
  13     public static synchronized StandardVariableBuilder<?> get() {
  14         if(INSTANCE == null) {
  15             INSTANCE = new StandardVariableBuilder<>();
  16         }
  17         return INSTANCE;
  18     }
  19
  20     @Override
  21     public Variable buildChild(ReadGraph graph, Variable parent, VariableNode<Node> node, Resource child) {
  22         return new StandardGraphChildVariable(parent, node, child);
  23     }
  24
  25     @Override
  26     public Variable buildProperty(ReadGraph graph, Variable parent, VariableNode<Node> node, Resource subject, Resource predicate) throws DatabaseException {
  27         return new StandardGraphPropertyVariable(graph, parent, node, subject, predicate);
  28     }
  29
  30 }