1 files changed, 122 insertions, 0 deletions
diff --git a/src/uk/org/ury/database/DatabaseDriver.java b/src/uk/org/ury/database/DatabaseDriver.java
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+++ b/src/uk/org/ury/database/DatabaseDriver.java
@@ -0,0 +1,122 @@
+package uk.org.ury.database;
+
+import java.sql.Connection;
+import java.sql.DriverManager;
+import java.sql.ResultSet;
+import java.sql.SQLException;
+import java.sql.Statement;
+
+import uk.org.ury.database.exceptions.ConnectionFailureException;
+import uk.org.ury.database.exceptions.MissingCredentialsException;
+
+
+/**
+ * A database connection manager that connects to the URY databases 
+ * using suitably privileged accounts, and handles the processing 
+ * of SQL queries.
+ *
+ * @author Matt Windsor
+ *
+ */
+
+public class DatabaseDriver
+{ 
+  /* The JDBC path used to connect to the URY database. */
+  private String DATABASE_PATH = "jdbc:postgresql://localhost/membership";
+  
+  /* The database connection. */
+  private Connection conn;
+  
+  
+  /**
+   * Construct a new DatabaseDriver with the given user class.
+   * 
+   * @param userclass  The user class to log in to the database with.
+   * 
+   * @throws           IllegalArgumentException if the user class is 
+   *                   not supported (this should not happen).
+   *                   
+   * @throws           MissingCredentialsException if the user class 
+   *                   login credentials could not be loaded.
+   *                   
+   * @throws           ConnectionFailureException if the database 
+   *                   backend failed to connect to the database 
+   *                   server.
+   */
+  
+  public
+  DatabaseDriver (UserClass userclass) throws MissingCredentialsException, ConnectionFailureException
+  { 
+    DatabaseLogin login = null;
+    
+    switch (userclass)
+    {
+    case READ_ONLY:
+      login = DatabaseLogin.getLoginFromFile ("read_only.txt");
+      break;
+    case READ_WRITE:
+      login = DatabaseLogin.getLoginFromFile ("read_write.txt");
+    default:
+      throw new IllegalArgumentException ("Unused user class.");
+    }
+
+
+    try
+      {
+        System.out.println ("Trying to acquire connection...");
+        
+        connect (login);
+        
+        System.out.println ("...connection succeeded.");
+      }
+    catch (SQLException e)
+      {
+        throw new ConnectionFailureException (e.getMessage ());
+      }
+
+  }
+  
+  
+  public void
+  connect (DatabaseLogin login) throws SQLException
+  {
+    if (login == null)
+      throw new IllegalArgumentException ("Supplied null login.");
+    
+    if (login.getUsername () == null)
+      throw new IllegalArgumentException ("Login has no associated username.");
+    
+    if (login.getPassword () == null)
+      throw new IllegalArgumentException ("Login has no associated password.");
+    
+    conn = DriverManager.getConnection (DATABASE_PATH,
+                                        login.getUsername (),
+                                        login.getPassword ());
+  }
+  
+  
+  /**
+   * Execute a SQL statement.
+   * 
+   * @param sql  The SQL statement to execute.
+   * 
+   * @return     the JDBC results set.
+   */
+  
+  public ResultSet
+  executeQuery (String sql)
+  {
+    try 
+      {
+        Statement st = conn.createStatement ();
+        st.setFetchSize (50);
+        
+        return st.executeQuery (sql);
+      }
+    catch (SQLException e)
+      {
+        e.printStackTrace ();
+        return null;
+      }
+  }
+}