How to use

retrieveInstances

method

in

weka.experiment.InstanceQuery

/**
 * Makes a database query using the query set through the -Q option to convert
 * a table into a set of instances
 * 
 * @return the instances contained in the result of the query
 * @throws Exception if an error occurs
 */
public Instances retrieveInstances() throws Exception {
 return retrieveInstances(m_Query);
}

/**
 * Makes a database query using the query set through the -Q option to convert
 * a table into a set of instances
 * 
 * @return the instances contained in the result of the query
 * @throws Exception if an error occurs
 */
public Instances retrieveInstances() throws Exception {
 return retrieveInstances(m_Query);
}

/**
 * Queries a database to load results from the specified table name. The
 * database connection must have already made by m_InstanceQuery.
 * 
 * @param tableName the name of the table containing results to retrieve.
 */
protected void setInstancesFromDatabaseTable(String tableName) {
 try {
  m_FromLab.setText("Reading from database, please wait...");
  final Instances i =
   m_InstanceQuery.retrieveInstances("SELECT * FROM " + tableName);
  SwingUtilities.invokeAndWait(new Runnable() {
   @Override
   public void run() {
    setInstances(i);
   }
  });
  m_InstanceQuery.disconnectFromDatabase();
 } catch (Exception ex) {
  m_FromLab.setText(ex.getMessage());
 }
}

/**
 * Queries a database to load results from the specified table name. The
 * database connection must have already made by m_InstanceQuery.
 * 
 * @param tableName the name of the table containing results to retrieve.
 */
protected void setInstancesFromDatabaseTable(String tableName) {
 try {
  m_FromLab.setText("Reading from database, please wait...");
  final Instances i =
   m_InstanceQuery.retrieveInstances("SELECT * FROM " + tableName);
  SwingUtilities.invokeAndWait(new Runnable() {
   @Override
   public void run() {
    setInstances(i);
   }
  });
  m_InstanceQuery.disconnectFromDatabase();
 } catch (Exception ex) {
  m_FromLab.setText(ex.getMessage());
 }
}

 @Override
 public void run() {
  try {
   m_Log.statusMessage("Reading from database...");
   final Instances i = iq.retrieveInstances();
   SwingUtilities.invokeAndWait(new Runnable() {
    public void run() {
     setInstances(new Instances(i));
    }
   });
   iq.disconnectFromDatabase();
  } catch (Exception ex) {
   m_Log.statusMessage("Problem executing DB query " + m_SQLQ);
   JOptionPane.showMessageDialog(PreprocessPanel.this,
    "Couldn't read from database:\n" + ex.getMessage(),
    "Load Instances", JOptionPane.ERROR_MESSAGE);
  }
  m_IOThread = null;
 }
};

 @Override
 public void run() {
  try {
   m_Log.statusMessage("Reading from database...");
   final Instances i = iq.retrieveInstances();
   SwingUtilities.invokeAndWait(new Runnable() {
    public void run() {
     setInstances(new Instances(i));
    }
   });
   iq.disconnectFromDatabase();
  } catch (Exception ex) {
   m_Log.statusMessage("Problem executing DB query " + m_SQLQ);
   JOptionPane.showMessageDialog(PreprocessPanel.this,
    "Couldn't read from database:\n" + ex.getMessage(),
    "Load Instances", JOptionPane.ERROR_MESSAGE);
  }
  m_IOThread = null;
 }
};

Instances result = retrieveInstances(this, rs);
close(rs);

Instances result = retrieveInstances(this, rs);
close(rs);

Instances aha = iq.retrieveInstances();
iq.disconnectFromDatabase();

Instances aha = iq.retrieveInstances();
iq.disconnectFromDatabase();

Instances data = null;
 try {
   DatabaseUtils utils = new DatabaseUtils();
   InstanceQuery query = new InstanceQuery();
   query.setUsername(username);
   query.setPassword(password);
   query.setQuery(pSql);
   data = query.retrieveInstances();
   data.setRelationName(pInstanceRelationName);
   if (data.classIndex() == -1)
   {
      data.setClassIndex(data.numAttributes() - 1);
   }
         // this line will print out your header + data. 
         // add your header information to your question.
   System.out.println(data)
 } 
   catch (Exception e) {
   throw new RuntimeException(e);
 }

m_FromLab.setText("Getting experiment index");
Instances index =
 m_InstanceQuery.retrieveInstances("SELECT * FROM "
  + InstanceQuery.EXP_INDEX_TABLE);
if (index.numInstances() == 0) {

m_FromLab.setText("Getting experiment index");
Instances index =
 m_InstanceQuery.retrieveInstances("SELECT * FROM "
  + InstanceQuery.EXP_INDEX_TABLE);
if (index.numInstances() == 0) {

iq.setSparseData(m_CreateSparseData);
result = iq.retrieveInstances();

iq.setSparseData(m_CreateSparseData);
result = iq.retrieveInstances();