querydsl-core/src/main/java/com/mysema/query/types/ExtractorVisitor.java

@@ -0,0 +1,64 @@
+package com.mysema.query.types;
+
+import com.mysema.query.types.Constant;
+import com.mysema.query.types.Custom;
+import com.mysema.query.types.Expr;
+import com.mysema.query.types.FactoryExpression;
+import com.mysema.query.types.Operation;
+import com.mysema.query.types.Param;
+import com.mysema.query.types.Path;
+import com.mysema.query.types.SubQueryExpression;
+import com.mysema.query.types.Visitor;
+
+/**
+ * @author tiwe
+ *
+ */
+public class ExtractorVisitor implements Visitor{
+
+    private Expr<?> expr;
+    
+    public ExtractorVisitor(Expr<?> e) {
+        e.accept(this);
+    }
+    
+    @Override
+    public void visit(Constant<?> expr) {
+        this.expr = expr.asExpr();
+    }
+
+    @Override
+    public void visit(Custom<?> expr) {
+        this.expr = expr.asExpr();
+    }
+
+    @Override
+    public void visit(FactoryExpression<?> expr) {
+        this.expr = expr.asExpr();
+    }
+
+    @Override
+    public void visit(Operation<?> expr) {
+        this.expr = expr.asExpr();
+    }
+
+    @Override
+    public void visit(Path<?> expr) {
+        this.expr = expr.asExpr();
+    }
+
+    @Override
+    public void visit(SubQueryExpression<?> expr) {
+        this.expr = expr.asExpr();
+    }
+
+    @Override
+    public void visit(Param<?> expr) {
+        this.expr = expr.asExpr();
+    }
+
+    public Expr<?> getExpr() {
+        return expr;
+    }
+    
+}