Example usage for weka.experiment InstanceQuery isConnected

Introduction

In this page you can find the example usage for weka.experiment InstanceQuery isConnected.

Prototype

public boolean isConnected() 

Source Link

Document

Returns true if a database connection is active.

Usage

From source file:adams.gui.visualization.instance.InstanceExplorer.java

License:Open Source License

/**
 * pops up SQL Viewer for SQL statement.
 *//*w ww  .ja  v a 2s . c  o  m*/
public void loadDataFromDatabase() {
    InstanceQuery query;
    List<InstanceContainer> data;
    Instances dataset;
    Instance inst;
    int i;

    if (m_LoadFromDatabaseDialog == null) {
        if ((getParentFrame() != null) && (getParentFrame() instanceof JFrame))
            m_LoadFromDatabaseDialog = new SqlViewerDialog((JFrame) getParentFrame());
        else
            m_LoadFromDatabaseDialog = new SqlViewerDialog(null);
    }

    m_LoadFromDatabaseDialog.setVisible(true);
    if (m_LoadFromDatabaseDialog.getReturnValue() != JOptionPane.OK_OPTION)
        return;

    try {
        showStatus("Executing query: " + m_LoadFromDatabaseDialog.getQuery());
        query = new InstanceQuery();
        query.setDatabaseURL(m_LoadFromDatabaseDialog.getURL());
        query.setUsername(m_LoadFromDatabaseDialog.getUser());
        query.setPassword(m_LoadFromDatabaseDialog.getPassword());
        query.setQuery(m_LoadFromDatabaseDialog.getQuery());
        query.setSparseData(m_LoadFromDatabaseDialog.getGenerateSparseData());
        if (query.isConnected())
            query.disconnectFromDatabase();
        query.connectToDatabase();

        showStatus("Loading data...");
        data = new ArrayList<>();
        dataset = query.retrieveInstances();
        for (i = 0; i < dataset.numInstances(); i++) {
            inst = new Instance();
            inst.set(dataset.instance(i));
            inst.setID(dataset.relationName() + "." + i);
            data.add(getContainerManager().newContainer(inst));
            showStatus("Loading data " + (i + 1) + "/" + dataset.numInstances());
        }
        loadData(dataset, data);
    } catch (Exception e) {
        GUIHelper.showErrorMessage(this, "Failed to load data from database:\n" + Utils.throwableToString(e),
                "Database error");
    }

    showStatus("");
}

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