- Work on drivers:

	- add basic PostgreSQL driver;
	- ConnectionData is now the same for all drivers
	- remove useless QIRDriver
	- minor changes in OracleDriver
- Cleanup in IQIRVisitor
- Minor changes

.gitignore

@@ -2,4 +2,7 @@
 .classpath
 .externalToolBuilders
 .project
+.checkstyle
+.checkstyle_checks.xml
+.settings/
 qir.jar

build_eclipse.xml

@@ -4,6 +4,7 @@
   <target name="CreateJar" description="Create Jar file">
     <jar jarfile="qir.jar">
       <fileset dir="bin"/>
+   	  <fileset dir="src"/>
     </jar>
   </target>
 

src/qir/driver/ConnectionData.java

+package qir.driver;
+
+public class ConnectionData {
+    public final String sid;
+    public final String serverName;
+    public final int portNumber;
+    public final String userName;
+    public final String password;
+
+    public ConnectionData(String sid, String serverName, int portNumber, String userName, String password) {
+        this.sid = sid;
+        this.serverName = serverName;
+        this.portNumber = portNumber;
+        this.userName = userName;
+        this.password = password;
+    }
+}

src/qir/driver/DBDriver.java

 package qir.driver;
 
+import java.sql.Connection;
+import java.sql.SQLException;
+
 import qir.ast.*;
 import qir.ast.data.*;
 
 public abstract class DBDriver {
+    protected Connection conn;
+
+    public abstract void openConnection(ConnectionData connData) throws SQLException;
+
+    public void closeConnection() throws SQLException {
+        if (conn == null)
+            return;
+        conn.close();
+        conn = null;
+    }
+
     public abstract QIRList run(QIRNode root);
 }
\ No newline at end of file

src/qir/driver/OracleDriver.java

@@ -10,15 +10,16 @@ import oracle.jdbc.pool.*;
 import qir.ast.*;
 import qir.ast.data.*;
 import qir.ast.value.*;
+import qir.driver.ConnectionData;
 
 /**
- * This driver is the intermediate between QIR and the Oracle database. This class is temporary. The
- * database should ultimately take a QIR tree directly.
+ * This driver is the intermediate between QIR and the Oracle database.
  */
 public class OracleDriver extends DBDriver {
-    private final Connection conn;
-
-    public OracleDriver(ConnectionData data) throws SQLException {
+    @Override
+    public void openConnection(ConnectionData data) throws SQLException {
+        if (conn != null)
+            closeConnection();
         String connString = "jdbc:oracle:thin:@" + data.serverName + ":" + data.portNumber + ":" + data.sid;
         OracleDataSource ods = new OracleDataSource();
         ods.setUser(data.userName);
@@ -26,6 +27,7 @@ public class OracleDriver extends DBDriver {
         ods.setURL(connString);
         ods.setLoginTimeout(1000);
         conn = ods.getConnection();
+        ods.close();
     }
 
     @Override
@@ -45,22 +47,6 @@ public class OracleDriver extends DBDriver {
         }
     }
 
-    public static class ConnectionData {
-        private final String sid;
-        private final String serverName;
-        private final int portNumber;
-        private final String userName;
-        private final String password;
-
-        public ConnectionData(String sid, String serverName, int portNumber, String userName, String password) {
-            this.sid = sid;
-            this.serverName = serverName;
-            this.portNumber = portNumber;
-            this.userName = userName;
-            this.password = password;
-        }
-    }
-
     private void enableWalnut() throws SQLException {
         // warm up database
         String query = "select * from emp";

src/qir/driver/PostgreSQLDriver.java

+package qir.driver;
+
+import java.sql.*;
+import java.util.*;
+
+import com.oracle.truffle.api.source.*;
+
+import qir.ast.*;
+import qir.ast.data.*;
+import qir.ast.value.*;
+import qir.driver.ConnectionData;
+import qir.util.QIRPrintVisitor;
+
+/**
+ * This driver is the intermediate between QIR and the Oracle database. This class is temporary. The
+ * database should ultimately take a QIR tree directly.
+ */
+public class PostgreSQLDriver extends DBDriver {
+    @Override
+    public void openConnection(ConnectionData connData) throws SQLException {
+        if (conn != null)
+            closeConnection();
+        String url = "jdbc:postgresql://" + connData.serverName + ":" + connData.portNumber + "/" + connData.sid;
+        Properties props = new Properties();
+        props.setProperty("user", connData.userName);
+        props.setProperty("password", connData.password);
+        conn = DriverManager.getConnection(url, props);
+    }
+
+    @Override
+    public QIRList run(QIRNode root) {
+        QIROracleVisitor visitor = new QIROracleVisitor();
+        QIRPrintVisitor debugVisitor = new QIRPrintVisitor();
+        String query = root.accept(visitor);
+        System.out.println("Query: " + query);
+        System.out.println("Query qir: " + root.accept(debugVisitor));
+        try {
+            QIRList result = executeQuery(query);
+            System.out.println("Results qir: " + result.accept(debugVisitor));
+            return result;
+        } catch (SQLException e) {
+            e.printStackTrace();
+            return null;
+        }
+    }
+
+    private QIRList executeQuery(String query) throws SQLException {
+        try (Statement stmt = conn.createStatement()) {
+            ResultSet rs = stmt.executeQuery(query);
+            int columnCount = rs.getMetaData().getColumnCount();
+            QIRList result = QIRLnil.getInstance();
+            Stack<QIRTuple> tmp = new Stack<>();
+            QIRNode data;
+            while (rs.next()) {
+                QIRTuple newTuple = QIRTnil.getInstance();
+                for (int i = columnCount; i >= 1; i--) {
+                    switch (rs.getMetaData().getColumnType(i)) {
+                        case Types.NUMERIC: {
+                            // TODO: Handle overflow
+                            data = new QIRNumber(SourceSection.createUnavailable("QIRNode", "QIRNumber"), rs.getLong(i));
+                            break;
+                        }
+                        default: {
+                            data = new QIRString(SourceSection.createUnavailable("QIRNode", "QIRString"), rs.getString(i));
+                            break;
+                        }
+                    }
+                    newTuple = new QIRTcons(SourceSection.createUnavailable("QIRNode", "QIRTcons"), rs.getMetaData().getColumnLabel(i), data, newTuple);
+                }
+                tmp.push(newTuple);
+            }
+            while (!tmp.isEmpty())
+                result = new QIRLcons(null, tmp.pop(), result);
+            return result;
+        }
+    }
+}
\ No newline at end of file

src/qir/driver/QIRDriver.java

-package qir.driver;
-
-import qir.ast.*;
-import qir.ast.data.*;
-import qir.util.*;
-
-/**
- * WORK IN PROGRESS: TODO: Add interface to stream results; add interface to get database info
- * (table exists?, table schema, ...).
- */
-public class QIRDriver {
-    private final DBDriver defaultDriver;
-
-    public QIRDriver(DBDriver defaultDriver) {
-        this.defaultDriver = defaultDriver;
-    }
-
-    public QIRList run(QIRNode root) {
-        QIRPrintVisitor debugVisitor = new QIRPrintVisitor();
-
-        System.out.println(root.accept(debugVisitor));
-        try {
-            return defaultDriver.run(root);
-        } catch (Exception e) {
-            e.printStackTrace();
-            return null;
-        }
-    }
-}
\ No newline at end of file

src/qir/util/IQIRVisitor.java

@@ -25,11 +25,14 @@ public interface IQIRVisitor<T> {
     public abstract T visit(QIROrder qirOrder);
 
     public default T visit(QIROperator qirOperator) {
-    	throw new UnsupportedOperationException(this.getClass().getSimpleName() + " error: unsupported operator.");
+        throw new UnsupportedOperationException("Error: unsupported operator " + qirOperator.getClass().getSimpleName() + ".");
     }
 
+    /**
+     * @param qirVariable A variable that should have been handled elsewhere.
+     */
     public default T visit(QIRVariable qirVariable) {
-    	throw new UnsupportedOperationException(this.getClass().getSimpleName() + " error: we should not visit a QIRVariable.");
+        throw new UnsupportedOperationException("Error: we should not visit a QIRVariable.");
     }
 
     public abstract T visit(QIRLambda qirLambda);
@@ -86,6 +89,9 @@ public interface IQIRVisitor<T> {
 
     public abstract T visit(QIRTruffleNode qirTruffleNode);
 
+    /**
+     * @param qirNode An unsupported node.
+     */
     public default T visit(QIRNode qirNode) {
         throw new UnsupportedOperationException(this.getClass().getSimpleName() + " error: unsupported node.");
     }