de.uniluebeck.itm.spyglass.gui.databinding.ComboBoxEditingSupport.java Source code

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Here is the source code for de.uniluebeck.itm.spyglass.gui.databinding.ComboBoxEditingSupport.java

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/*
 * ----------------------------------------------------------------------
 * This file is part of the WSN visualization framework SpyGlass. Copyright (C) 2004-2007 by the
 * SwarmNet (www.swarmnet.de) project SpyGlass is free software;
 * you can redistribute it and/or modify it under the terms of the BSD License.
 * Refer to spyglass-licence.txt file in the root of the SpyGlass source tree for further details.
 * ------------------------------------------------------------------------
 */
package de.uniluebeck.itm.spyglass.gui.databinding;

import org.apache.log4j.Logger;
import org.eclipse.core.databinding.Binding;
import org.eclipse.core.databinding.DataBindingContext;
import org.eclipse.core.databinding.UpdateValueStrategy;
import org.eclipse.core.databinding.beans.BeansObservables;
import org.eclipse.core.databinding.observable.value.IObservableValue;
import org.eclipse.jface.databinding.swt.SWTObservables;
import org.eclipse.jface.databinding.viewers.ObservableValueEditingSupport;
import org.eclipse.jface.viewers.CellEditor;
import org.eclipse.jface.viewers.ColumnViewer;
import org.eclipse.jface.viewers.ComboBoxCellEditor;
import org.eclipse.jface.viewers.TableViewer;
import org.eclipse.jface.viewers.ViewerCell;
import org.eclipse.swt.SWT;
import org.eclipse.swt.custom.CCombo;
import org.eclipse.swt.widgets.Combo;

import de.uniluebeck.itm.spyglass.gui.databinding.converter.StatisticOperationConverter;
import de.uniluebeck.itm.spyglass.util.SpyglassLogger;
import de.uniluebeck.itm.spyglass.util.SpyglassLoggerFactory;

//--------------------------------------------------------------------------------
/**
 * Creates an observable {@link CCombo} box.
 *
 * @author Sebastian Ebers
 *
 */
public class ComboBoxEditingSupport extends ObservableValueEditingSupport {

    private CellEditor cellEditor;
    private DataBindingContext dbc;
    private String elementName = "value";
    private static final Logger log = SpyglassLoggerFactory.getLogger(ComboBoxEditingSupport.class);
    private String getterMethodName;

    // --------------------------------------------------------------------------------
    /**
     * Constructor
     *
     * @param viewer
     *            the column viewer
     * @param dbc
     *            the data binding context
     * @param elementName
     *            the name of the model's element
     * @param values
     *            the values to be shown in the {@link Combo} box
     *
     */
    public ComboBoxEditingSupport(final ColumnViewer viewer, final DataBindingContext dbc, final String elementName,
            final String[] values) {
        super(viewer, dbc);
        this.dbc = dbc;
        this.elementName = elementName;
        cellEditor = new ComboBoxCellEditor(((TableViewer) viewer).getTable(), values, SWT.READ_ONLY);
        setGetterMethodName();
    }

    // --------------------------------------------------------------------------------
    /**
     */
    private void setGetterMethodName() {
        getterMethodName = "get" + elementName.substring(0, 1).toUpperCase() + elementName.substring(1);
    }

    @Override
    protected CellEditor getCellEditor(final Object element) {

        /*
         * Before the CellEditor is returned, the CCombo's index is set according to the object
         * currently visible in the cell's row. Since only one CellEditor is used for the complete
         * table, the selection index complies with the last selection - no matter in which row it
         * took place! To obtain the expected behavior, the selection index is set up manually.
         */

        try {

            // determine index of the combo box's string which matches the currently selected one in
            // the model ...
            final String selectedElement = element.getClass().getMethod(getterMethodName, new Class<?>[] {})
                    .invoke(element).toString();
            final String[] items = ((CCombo) cellEditor.getControl()).getItems();
            for (int i = 0; i < items.length; i++) {
                if (items[i].equals(selectedElement)) {
                    // ... and set the combo box's selection appropriately
                    ((CCombo) cellEditor.getControl()).select(i);
                }
            }
        } catch (final Exception e) {
            // setting up the correct selection index might fail but it has only limited impact on
            // the functionality. Additionally there is nothing the user can do so no window is to
            // be displayed to display the error message to the user.
            ((SpyglassLogger) log).error(
                    "An exception occured while trying to determine the selected index of the combo box.", e,
                    false);
        }
        return cellEditor;
    }

    @Override
    protected IObservableValue doCreateCellEditorObservable(final CellEditor cellEditor) {
        return SWTObservables.observeSelection(cellEditor.getControl());

    }

    @Override
    protected IObservableValue doCreateElementObservable(final Object element, final ViewerCell cell) {
        return BeansObservables.observeValue(dbc.getValidationRealm(), element, elementName);
    }

    @Override
    protected Binding createBinding(final IObservableValue target, final IObservableValue model) {
        return dbc.bindValue(target, model,
                new UpdateValueStrategy(UpdateValueStrategy.POLICY_CONVERT)
                        .setConverter(new StatisticOperationConverter(String.class, Enum.class)),
                new UpdateValueStrategy(UpdateValueStrategy.POLICY_CONVERT)
                        .setConverter(new StatisticOperationConverter(Enum.class, String.class)));
    }

}