- A QIR visitor throws generic exception for unsupported node

- Better HBase driver (adds filter)

src/qir/driver/IQIRVisitor.java

@@ -7,96 +7,177 @@ import qir.ast.expression.logic.*;
 import qir.ast.expression.relational.*;
 import qir.ast.operator.*;
 import qir.ast.value.*;
+import qir.util.QIRException;
 
 /**
  * Implement IQIRVisitor<T> to visit a QIR tree. The return type of the visit functions in the
  * visitor and the accept functions in the QIR nodes is T.
  */
 public interface IQIRVisitor<T> {
-    public abstract T visit(final QIRProject qirProject);
+    public default T visit(final QIRProject qirProject) {
+        throw new QIRException(this.getClass().getSimpleName() + " error: unsupported QIR node " + qirProject.getClass().getSimpleName() + ".");
+    }
 
-    public abstract T visit(final QIRScan qirScan);
+    public default T visit(final QIRScan qirScan) {
+        throw new QIRException(this.getClass().getSimpleName() + " error: unsupported QIR node " + qirScan.getClass().getSimpleName() + ".");
+    }
 
-    public abstract T visit(final QIRFilter qirFilter);
+    public default T visit(final QIRFilter qirFilter) {
+        throw new QIRException(this.getClass().getSimpleName() + " error: unsupported QIR node " + qirFilter.getClass().getSimpleName() + ".");
+    }
 
-    public abstract T visit(final QIRGroupBy qirGroup);
+    public default T visit(final QIRGroupBy qirGroup) {
+        throw new QIRException(this.getClass().getSimpleName() + " error: unsupported QIR node " + qirGroup.getClass().getSimpleName() + ".");
+    }
 
-    public abstract T visit(final QIRSortBy qirOrder);
+    public default T visit(final QIRSortBy qirOrder) {
+        throw new QIRException(this.getClass().getSimpleName() + " error: unsupported QIR node " + qirOrder.getClass().getSimpleName() + ".");
+    }
 
-    public abstract T visit(final QIRJoin qirJoin);
+    public default T visit(final QIRJoin qirJoin) {
+        throw new QIRException(this.getClass().getSimpleName() + " error: unsupported QIR node " + qirJoin.getClass().getSimpleName() + ".");
+    }
 
-    public abstract T visit(final QIRLeftJoin qirJoin);
+    public default T visit(final QIRLeftJoin qirJoin) {
+        throw new QIRException(this.getClass().getSimpleName() + " error: unsupported QIR node " + qirJoin.getClass().getSimpleName() + ".");
+    }
 
-    public abstract T visit(final QIRRightJoin qirJoin);
+    public default T visit(final QIRRightJoin qirJoin) {
+        throw new QIRException(this.getClass().getSimpleName() + " error: unsupported QIR node " + qirJoin.getClass().getSimpleName() + ".");
+    }
 
-    public abstract T visit(final QIRLimit qirLimit);
+    public default T visit(final QIRLimit qirLimit) {
+        throw new QIRException(this.getClass().getSimpleName() + " error: unsupported QIR node " + qirLimit.getClass().getSimpleName() + ".");
+    }
 
-    public abstract <DBRepr, ConnData> T visit(final QIRDBNode<DBRepr, ConnData> qirDBNode);
+    public default <DBRepr, ConnData> T visit(final QIRDBNode<DBRepr, ConnData> qirDBNode) {
+        throw new QIRException(this.getClass().getSimpleName() + " error: unsupported QIR node " + qirDBNode.getClass().getSimpleName() + ".");
+    }
 
-    public abstract T visit(final QIRBuiltin qirBuiltin);
+    public default T visit(final QIRBuiltin qirBuiltin) {
+        throw new QIRException(this.getClass().getSimpleName() + " error: unsupported QIR node " + qirBuiltin.getClass().getSimpleName() + ".");
+    }
 
-    public abstract T visit(final QIRVariable qirVariable);
+    public default T visit(final QIRVariable qirVariable) {
+        throw new QIRException(this.getClass().getSimpleName() + " error: unsupported QIR node " + qirVariable.getClass().getSimpleName() + ".");
+    }
 
-    public abstract T visit(final QIRLambda qirLambda);
+    public default T visit(final QIRLambda qirLambda) {
+        throw new QIRException(this.getClass().getSimpleName() + " error: unsupported QIR node " + qirLambda.getClass().getSimpleName() + ".");
+    }
 
-    public abstract T visit(final QIRApply qirApply);
+    public default T visit(final QIRApply qirApply) {
+        throw new QIRException(this.getClass().getSimpleName() + " error: unsupported QIR node " + qirApply.getClass().getSimpleName() + ".");
+    }
 
-    public abstract T visit(final QIRIf qirIf);
+    public default T visit(final QIRIf qirIf) {
+        throw new QIRException(this.getClass().getSimpleName() + " error: unsupported QIR node " + qirIf.getClass().getSimpleName() + ".");
+    }
 
-    public abstract T visit(final QIRPlus qirPlus);
+    public default T visit(final QIRPlus qirPlus) {
+        throw new QIRException(this.getClass().getSimpleName() + " error: unsupported QIR node " + qirPlus.getClass().getSimpleName() + ".");
+    }
 
-    public abstract T visit(final QIRMinus qirMinus);
+    public default T visit(final QIRMinus qirMinus) {
+        throw new QIRException(this.getClass().getSimpleName() + " error: unsupported QIR node " + qirMinus.getClass().getSimpleName() + ".");
+    }
 
-    public abstract T visit(final QIRStar qirStar);
+    public default T visit(final QIRStar qirStar) {
+        throw new QIRException(this.getClass().getSimpleName() + " error: unsupported QIR node " + qirStar.getClass().getSimpleName() + ".");
+    }
 
-    public abstract T visit(final QIRDiv qirDiv);
+    public default T visit(final QIRDiv qirDiv) {
+        throw new QIRException(this.getClass().getSimpleName() + " error: unsupported QIR node " + qirDiv.getClass().getSimpleName() + ".");
+    }
 
-    public abstract T visit(final QIRMod qirMod);
+    public default T visit(final QIRMod qirMod) {
+        throw new QIRException(this.getClass().getSimpleName() + " error: unsupported QIR node " + qirMod.getClass().getSimpleName() + ".");
+    }
 
-    public abstract T visit(final QIRAnd qirAnd);
+    public default T visit(final QIRAnd qirAnd) {
+        throw new QIRException(this.getClass().getSimpleName() + " error: unsupported QIR node " + qirAnd.getClass().getSimpleName() + ".");
+    }
 
-    public abstract T visit(final QIROr qirOr);
+    public default T visit(final QIROr qirOr) {
+        throw new QIRException(this.getClass().getSimpleName() + " error: unsupported QIR node " + qirOr.getClass().getSimpleName() + ".");
+    }
 
-    public abstract T visit(final QIREqual qirEqual);
+    public default T visit(final QIREqual qirEqual) {
+        throw new QIRException(this.getClass().getSimpleName() + " error: unsupported QIR node " + qirEqual.getClass().getSimpleName() + ".");
+    }
 
-    public abstract T visit(final QIRLowerOrEqual qirLowerOrEqual);
+    public default T visit(final QIRLowerOrEqual qirLowerOrEqual) {
+        throw new QIRException(this.getClass().getSimpleName() + " error: unsupported QIR node " + qirLowerOrEqual.getClass().getSimpleName() + ".");
+    }
 
-    public abstract T visit(final QIRLowerThan qirLowerThan);
+    public default T visit(final QIRLowerThan qirLowerThan) {
+        throw new QIRException(this.getClass().getSimpleName() + " error: unsupported QIR node " + qirLowerThan.getClass().getSimpleName() + ".");
+    }
 
-    public abstract T visit(final QIRNot qirNot);
+    public default T visit(final QIRNot qirNot) {
+        throw new QIRException(this.getClass().getSimpleName() + " error: unsupported QIR node " + qirNot.getClass().getSimpleName() + ".");
+    }
 
-    public abstract <DBRepr, ConnData> T visit(final QIRTable<DBRepr, ConnData> qirTable);
+    public default <DBRepr, ConnData> T visit(final QIRTable<DBRepr, ConnData> qirTable) {
+        throw new QIRException(this.getClass().getSimpleName() + " error: unsupported QIR node " + qirTable.getClass().getSimpleName() + ".");
+    }
 
-    public abstract T visit(final QIRLnil qirLnil);
+    public default T visit(final QIRLnil qirLnil) {
+        throw new QIRException(this.getClass().getSimpleName() + " error: unsupported QIR node " + qirLnil.getClass().getSimpleName() + ".");
+    }
 
-    public abstract T visit(final QIRLcons qirLcons);
+    public default T visit(final QIRLcons qirLcons) {
+        throw new QIRException(this.getClass().getSimpleName() + " error: unsupported QIR node " + qirLcons.getClass().getSimpleName() + ".");
+    }
 
-    public abstract T visit(final QIRLdestr qirLdestr);
+    public default T visit(final QIRLdestr qirLdestr) {
+        throw new QIRException(this.getClass().getSimpleName() + " error: unsupported QIR node " + qirLdestr.getClass().getSimpleName() + ".");
+    }
 
-    public abstract T visit(final QIRTnil qirTnil);
+    public default T visit(final QIRTnil qirTnil) {
+        throw new QIRException(this.getClass().getSimpleName() + " error: unsupported QIR node " + qirTnil.getClass().getSimpleName() + ".");
+    }
 
-    public abstract T visit(final QIRTcons qirTcons);
+    public default T visit(final QIRTcons qirTcons) {
+        throw new QIRException(this.getClass().getSimpleName() + " error: unsupported QIR node " + qirTcons.getClass().getSimpleName() + ".");
+    }
 
-    public abstract T visit(final QIRTdestr qirTdestr);
+    public default T visit(final QIRTdestr qirTdestr) {
+        throw new QIRException(this.getClass().getSimpleName() + " error: unsupported QIR node " + qirTdestr.getClass().getSimpleName() + ".");
+    }
 
-    public abstract T visit(final QIRString qirString);
+    public default T visit(final QIRString qirString) {
+        throw new QIRException(this.getClass().getSimpleName() + " error: unsupported QIR node " + qirString.getClass().getSimpleName() + ".");
+    }
 
-    public abstract T visit(final QIRNumber qirNumber);
+    public default T visit(final QIRNumber qirNumber) {
+        throw new QIRException(this.getClass().getSimpleName() + " error: unsupported QIR node " + qirNumber.getClass().getSimpleName() + ".");
+    }
 
-    public abstract T visit(final QIRBigNumber qirBigNumber);
+    public default T visit(final QIRBigNumber qirBigNumber) {
+        throw new QIRException(this.getClass().getSimpleName() + " error: unsupported QIR node " + qirBigNumber.getClass().getSimpleName() + ".");
+    }
 
-    public abstract T visit(final QIRDouble qirDouble);
+    public default T visit(final QIRDouble qirDouble) {
+        throw new QIRException(this.getClass().getSimpleName() + " error: unsupported QIR node " + qirDouble.getClass().getSimpleName() + ".");
+    }
 
-    public abstract T visit(final QIRBoolean qirBoolean);
+    public default T visit(final QIRBoolean qirBoolean) {
+        throw new QIRException(this.getClass().getSimpleName() + " error: unsupported QIR node " + qirBoolean.getClass().getSimpleName() + ".");
+    }
 
-    public abstract T visit(final QIRNull qirNull);
+    public default T visit(final QIRNull qirNull) {
+        throw new QIRException(this.getClass().getSimpleName() + " error: unsupported QIR node " + qirNull.getClass().getSimpleName() + ".");
+    }
 
-    public abstract T visit(final QIRTruffleNode qirTruffleNode);
+    public default T visit(final QIRTruffleNode qirTruffleNode) {
+        throw new QIRException(this.getClass().getSimpleName() + " error: unsupported QIR node " + qirTruffleNode.getClass().getSimpleName() + ".");
+    }
 
     /**
      * @param qirNode An unsupported node.
      */
     public default T visit(final QIRNode qirNode) {
-        throw new UnsupportedOperationException(this.getClass().getSimpleName() + " error: unsupported QIR node " + qirNode.getClass().getSimpleName() + ".");
+        throw new QIRException(this.getClass().getSimpleName() + " error: unsupported QIR node " + qirNode.getClass().getSimpleName() + ".");
     }
 }
\ No newline at end of file

src/qir/driver/hbase/HBaseQuery.java

@@ -16,6 +16,6 @@ public class HBaseQuery {
 
     @Override
     public String toString() {
-        return scan + "@" + tableName;
+        return "select " + scan.getAttributesMap().keySet().stream().map(x -> x + " ") + " from " + tableName + (scan.getFilter() != null ? " where " + scan.getFilter() : "");
     }
 }

src/qir/driver/hbase/QIRHBasePredicateVisitor.java

+package qir.driver.hbase;
+
+import org.apache.hadoop.hbase.filter.Filter;
+import org.apache.hadoop.hbase.filter.SingleColumnValueFilter;
+import org.apache.hadoop.hbase.filter.CompareFilter.CompareOp;
+
+import qir.ast.expression.relational.*;
+import qir.driver.IQIRVisitor;
+
+/**
+ * Translation from QIR query to SQL query in String format.
+ */
+final class QIRHBasePredicateVisitor implements IQIRVisitor<Filter> {
+    @Override
+    public final Filter visit(final QIREqual qirEqual) { // TODO: rowfilters?
+        return new SingleColumnValueFilter("default".getBytes(), qirEqual.left.accept(new QIRHBaseValueVisitor()).getBytes(), CompareOp.EQUAL,
+                        qirEqual.right.accept(new QIRHBaseValueVisitor()).getBytes());
+    }
+
+    @Override
+    public final Filter visit(final QIRLowerOrEqual qirLowerOrEqual) {
+        return new SingleColumnValueFilter("default".getBytes(), qirLowerOrEqual.left.accept(new QIRHBaseValueVisitor()).getBytes(), CompareOp.LESS_OR_EQUAL,
+                        qirLowerOrEqual.right.accept(new QIRHBaseValueVisitor()).getBytes());
+    }
+
+    @Override
+    public final Filter visit(final QIRLowerThan qirLowerThan) {
+        return new SingleColumnValueFilter("default".getBytes(), qirLowerThan.left.accept(new QIRHBaseValueVisitor()).getBytes(), CompareOp.LESS,
+                        qirLowerThan.right.accept(new QIRHBaseValueVisitor()).getBytes());
+    }
+}
\ No newline at end of file

src/qir/driver/hbase/QIRHBaseQueryVisitor.java

@@ -4,260 +4,43 @@ import org.apache.hadoop.hbase.client.Scan;
 
 import qir.ast.*;
 import qir.ast.data.*;
-import qir.ast.expression.arithmetic.*;
-import qir.ast.expression.logic.*;
-import qir.ast.expression.relational.*;
 import qir.ast.operator.*;
 import qir.ast.value.*;
 import qir.driver.IQIRVisitor;
 import qir.util.QIRException;
 
 /**
- * Translation from QIR to HBase query.
+ * Translation from QIR query to HBase query in {@link HBaseQuery} format.
  */
 final class QIRHBaseQueryVisitor implements IQIRVisitor<HBaseQuery> {
     @Override
-    public HBaseQuery visit(QIRProject qirProject) {
-        if (!(qirProject.formatter instanceof QIRLambda && ((QIRLambda) qirProject.formatter).body instanceof QIRLcons))
+    public final HBaseQuery visit(QIRProject qirProject) {
+        if (!(qirProject.formatter instanceof QIRLambda && ((QIRLambda) qirProject.formatter).body instanceof QIRTcons))
             throw new QIRException("QIR SQL Project not implemented for formatter type: " + qirProject.formatter.getClass());
         final HBaseQuery child = qirProject.child.accept(this);
 
-        for (QIRNode formatter = ((QIRLambda) qirProject.formatter).body; formatter instanceof QIRLcons; formatter = ((QIRLcons) formatter).tail)
-            child.scan.addColumn("default".getBytes(), ((String) ((QIRBaseValue<?>) ((QIRLcons) formatter).value).value).getBytes());
+        for (QIRNode formatter = ((QIRLambda) qirProject.formatter).body; formatter instanceof QIRTcons; formatter = ((QIRTcons) formatter).tail)
+            child.scan.addColumn("default".getBytes(), ((QIRTcons) formatter).accept(new QIRHBaseValueVisitor()).getBytes());
         return child;
     }
 
     @Override
-    public HBaseQuery visit(QIRScan qirScan) {
+    public final HBaseQuery visit(QIRScan qirScan) {
         return new HBaseQuery(new Scan(),
                         (String) ((QIRBaseValue<?>) ((QIRTable<?, ?>) qirScan.table).schemaName).value + ":" + (String) ((QIRBaseValue<?>) ((QIRTable<?, ?>) qirScan.table).tableName).value);
     }
 
     @Override
-    public HBaseQuery visit(QIRFilter qirFilter) {
-        // TODO Auto-generated method stub
-        return null;
-    }
-
-    @Override
-    public HBaseQuery visit(QIRGroupBy qirGroup) {
-        // TODO Auto-generated method stub
-        return null;
-    }
-
-    @Override
-    public HBaseQuery visit(QIRSortBy qirOrder) {
-        // TODO Auto-generated method stub
-        return null;
-    }
-
-    @Override
-    public HBaseQuery visit(QIRJoin qirJoin) {
-        // TODO Auto-generated method stub
-        return null;
-    }
-
-    @Override
-    public HBaseQuery visit(QIRLeftJoin qirJoin) {
-        // TODO Auto-generated method stub
-        return null;
-    }
-
-    @Override
-    public HBaseQuery visit(QIRRightJoin qirJoin) {
-        // TODO Auto-generated method stub
-        return null;
-    }
-
-    @Override
-    public HBaseQuery visit(QIRLimit qirLimit) {
-        // TODO Auto-generated method stub
-        return null;
+    public final HBaseQuery visit(QIRFilter qirFilter) {
+        if (!(qirFilter.filter instanceof QIRLambda))
+            throw new QIRException("QIR HBase Filter not implemented for filter type: " + qirFilter.filter.getClass());
+        final HBaseQuery child = qirFilter.child.accept(this);
+        child.scan.setFilter(((QIRLambda) qirFilter.filter).body.accept(new QIRHBasePredicateVisitor()));
+        return child;
     }
 
     @Override
-    public <DBRepr, ConnData> HBaseQuery visit(QIRDBNode<DBRepr, ConnData> qirDBNode) {
+    public final <DBRepr, ConnData> HBaseQuery visit(final QIRDBNode<DBRepr, ConnData> qirDBNode) {
         return (HBaseQuery) qirDBNode.translation;
     }
-
-    @Override
-    public HBaseQuery visit(QIRBuiltin qirBuiltin) {
-        // TODO Auto-generated method stub
-        return null;
-    }
-
-    @Override
-    public HBaseQuery visit(QIRVariable qirVariable) {
-        // TODO Auto-generated method stub
-        return null;
-    }
-
-    @Override
-    public HBaseQuery visit(QIRLambda qirLambda) {
-        // TODO Auto-generated method stub
-        return null;
-    }
-
-    @Override
-    public HBaseQuery visit(QIRApply qirApply) {
-        // TODO Auto-generated method stub
-        return null;
-    }
-
-    @Override
-    public HBaseQuery visit(QIRIf qirIf) {
-        // TODO Auto-generated method stub
-        return null;
-    }
-
-    @Override
-    public HBaseQuery visit(QIRPlus qirPlus) {
-        // TODO Auto-generated method stub
-        return null;
-    }
-
-    @Override
-    public HBaseQuery visit(QIRMinus qirMinus) {
-        // TODO Auto-generated method stub
-        return null;
-    }
-
-    @Override
-    public HBaseQuery visit(QIRStar qirStar) {
-        // TODO Auto-generated method stub
-        return null;
-    }
-
-    @Override
-    public HBaseQuery visit(QIRDiv qirDiv) {
-        // TODO Auto-generated method stub
-        return null;
-    }
-
-    @Override
-    public HBaseQuery visit(QIRMod qirMod) {
-        // TODO Auto-generated method stub
-        return null;
-    }
-
-    @Override
-    public HBaseQuery visit(QIRAnd qirAnd) {
-        // TODO Auto-generated method stub
-        return null;
-    }
-
-    @Override
-    public HBaseQuery visit(QIROr qirOr) {
-        // TODO Auto-generated method stub
-        return null;
-    }
-
-    @Override
-    public HBaseQuery visit(QIREqual qirEqual) {
-        // TODO Auto-generated method stub
-        return null;
-    }
-
-    @Override
-    public HBaseQuery visit(QIRLowerOrEqual qirLowerOrEqual) {
-        // TODO Auto-generated method stub
-        return null;
-    }
-
-    @Override
-    public HBaseQuery visit(QIRLowerThan qirLowerThan) {
-        // TODO Auto-generated method stub
-        return null;
-    }
-
-    @Override
-    public HBaseQuery visit(QIRNot qirNot) {
-        // TODO Auto-generated method stub
-        return null;
-    }
-
-    @Override
-    public <DBRepr, ConnData> HBaseQuery visit(QIRTable<DBRepr, ConnData> qirTable) {
-        // TODO Auto-generated method stub
-        return null;
-    }
-
-    @Override
-    public HBaseQuery visit(QIRLnil qirLnil) {
-        // TODO Auto-generated method stub
-        return null;
-    }
-
-    @Override
-    public HBaseQuery visit(QIRLcons qirLcons) {
-        // TODO Auto-generated method stub
-        return null;
-    }
-
-    @Override
-    public HBaseQuery visit(QIRLdestr qirLdestr) {
-        // TODO Auto-generated method stub
-        return null;
-    }
-
-    @Override
-    public HBaseQuery visit(QIRTnil qirTnil) {
-        // TODO Auto-generated method stub
-        return null;
-    }
-
-    @Override
-    public HBaseQuery visit(QIRTcons qirTcons) {
-        // TODO Auto-generated method stub
-        return null;
-    }
-
-    @Override
-    public HBaseQuery visit(QIRTdestr qirTdestr) {
-        // TODO Auto-generated method stub
-        return null;
-    }
-
-    @Override
-    public HBaseQuery visit(QIRString qirString) {
-        // TODO Auto-generated method stub
-        return null;
-    }
-
-    @Override
-    public HBaseQuery visit(QIRNumber qirNumber) {
-        // TODO Auto-generated method stub
-        return null;
-    }
-
-    @Override
-    public HBaseQuery visit(QIRBigNumber qirBigNumber) {
-        // TODO Auto-generated method stub
-        return null;
-    }
-
-    @Override
-    public HBaseQuery visit(QIRDouble qirDouble) {
-        // TODO Auto-generated method stub
-        return null;
-    }
-
-    @Override
-    public HBaseQuery visit(QIRBoolean qirBoolean) {
-        // TODO Auto-generated method stub
-        return null;
-    }
-
-    @Override
-    public HBaseQuery visit(QIRNull qirNull) {
-        // TODO Auto-generated method stub
-        return null;
-    }
-
-    @Override
-    public HBaseQuery visit(QIRTruffleNode qirTruffleNode) {
-        // TODO Auto-generated method stub
-        return null;
-    }
-
 }
\ No newline at end of file

src/qir/driver/hbase/QIRHBaseValueVisitor.java

+package qir.driver.hbase;
+
+import qir.ast.*;
+import qir.ast.data.*;
+import qir.ast.value.*;
+import qir.driver.IQIRVisitor;
+import qir.util.QIRException;
+
+/**
+ * Translation from QIR query to SQL query in String format.
+ */
+final class QIRHBaseValueVisitor implements IQIRVisitor<String> {
+    @Override
+    public final String visit(final QIRString qirString) {
+        return "'" + qirString.value + "'";
+    }
+
+    @Override
+    public final String visit(final QIRNumber qirNumber) {
+        return Long.toString(qirNumber.value);
+    }
+
+    @Override
+    public final String visit(final QIRBigNumber qirBigNumber) {
+        return qirBigNumber.value.toString();
+    }
+
+    @Override
+    public final String visit(final QIRDouble qirDouble) {
+        return qirDouble.value.toString();
+    }
+
+    @Override
+    public final String visit(final QIRBoolean qirBoolean) {
+        return qirBoolean.value ? "true" : "false";
+    }
+
+    @Override
+    public final String visit(final QIRNull qirNull) {
+        return "null";
+    }
+
+    @Override
+    public final String visit(final QIRVariable qirVariable) {
+        return qirVariable.id;
+    }
+
+    @Override
+    public final String visit(final QIRTcons qirTcons) {
+        final String value = qirTcons.value.accept(this);
+
+        if (value != qirTcons.id)
+            throw new QIRException(this.getClass().getSimpleName() + ": aliased column not unsupported.");
+        return value;
+    }
+
+    @Override
+    public final String visit(final QIRTdestr qirTdestr) {
+        return qirTdestr.colName;
+    }
+}
\ No newline at end of file

src/qir/driver/sql/QIRSQLStringVisitor.java

@@ -18,7 +18,7 @@ import qir.driver.IQIRVisitor;
 import qir.util.*;
 
 /**
- * Translation from QIR to SQL.
+ * Translation from QIR query to SQL query in String format.
  */
 final class QIRSQLStringVisitor implements IQIRVisitor<String> {
     private static String prefix = "_QIR_";
@@ -112,6 +112,13 @@ final class QIRSQLStringVisitor implements IQIRVisitor<String> {
         throw new QIRException("QIR SQL Join not implemented for filter type: " + qirJoin.filter.getClass());
     }
 
+    @Override
+    public final String visit(final QIRLimit qirLimit) {
+        if (qirLimit.limit instanceof QIRLambda)
+            return qirLimit.child.accept(this) + " limit " + ((QIRLambda) qirLimit.limit).body.accept(this);
+        return qirLimit.child.accept(this) + " limit " + qirLimit.limit.accept(this);
+    }
+
     @Override
     public final <DBRepr, ConnData> String visit(final QIRDBNode<DBRepr, ConnData> qirDBNode) {
         return (String) qirDBNode.translation;
@@ -122,13 +129,6 @@ final class QIRSQLStringVisitor implements IQIRVisitor<String> {
         return qirBuiltin.name;
     }
 
-    @Override
-    public final String visit(final QIRLimit qirLimit) {
-        if (qirLimit.limit instanceof QIRLambda)
-            return qirLimit.child.accept(this) + " limit " + ((QIRLambda) qirLimit.limit).body.accept(this);
-        return qirLimit.child.accept(this) + " limit " + qirLimit.limit.accept(this);
-    }
-
     @Override
     public final String visit(final QIRVariable qirVariable) {
         return qirVariable.id;