AbstractComboViewer.java

package org.openlca.app.viewers.combo;

import org.eclipse.jface.viewers.ArrayContentProvider;
import org.eclipse.jface.viewers.ViewerSorter;
import org.eclipse.nebula.jface.tablecomboviewer.TableComboViewer;
import org.eclipse.nebula.widgets.tablecombo.TableCombo;
import org.eclipse.swt.SWT;
import org.eclipse.swt.widgets.Composite;
import org.eclipse.ui.PlatformUI;
import org.openlca.app.util.UI;
import org.openlca.app.viewers.AbstractViewer;
import org.openlca.app.viewers.BaseNameSorter;

public abstract class AbstractComboViewer<T> extends
		AbstractViewer<T, TableComboViewer> {

	protected AbstractComboViewer(Composite parent) {
		super(parent);
	}

	public abstract Class<T> getType();

	@Override
	protected TableComboViewer createViewer(Composite parent) {
		TableCombo combo = new TableCombo(parent, SWT.READ_ONLY | SWT.BORDER);
		UI.gridData(combo, true, false).widthHint = 350;
		if (useColumnHeaders()) {
			if (useColumnBounds())
				combo.defineColumns(getColumnHeaders(), getColumnBounds());
			else
				combo.defineColumns(getColumnHeaders());
			combo.setShowTableHeader(true);
			combo.setShowTableLines(true);
		}
		combo.setDisplayColumnIndex(getDisplayColumn());
		TableComboViewer viewer = new TableComboViewer(combo);
		viewer.setContentProvider(ArrayContentProvider.getInstance());
		viewer.setLabelProvider(getLabelProvider());
		viewer.setSorter(getSorter());
		return viewer;
	}

	protected ViewerSorter getSorter() {
		return new BaseNameSorter();
	}

	private int[] getColumnBounds() {
		int[] columnBoundsPercentages = getColumnBoundsPercentages();
		int[] columnBoundsAbsolute = new int[columnBoundsPercentages.length];
		int total = PlatformUI.getWorkbench().getActiveWorkbenchWindow()
				.getShell().getSize().x / 2;
		for (int i = 0; i < columnBoundsPercentages.length; i++)
			columnBoundsAbsolute[i] = (int) (total / 100d * columnBoundsPercentages[i]);
		return columnBoundsAbsolute;
	}

	private boolean useColumnHeaders() {
		return getColumnHeaders() != null && getColumnHeaders().length > 0;
	}

	private boolean useColumnBounds() {
		return getColumnBoundsPercentages() != null
				&& getColumnBoundsPercentages().length > 0
				&& getColumnBoundsPercentages().length == getColumnHeaders().length;
	}

	/**
	 * Subclasses may override this for support of column headers for the table
	 * combo, if null or empty array is returned, the headers are not visible
	 * and the combo behaves like a standard combo
	 */
	protected String[] getColumnHeaders() {
		return null;
	}

	/**
	 * Subclasses may override this for support of column header bounds for the
	 * table combo, if null or empty array is returned or the number of array
	 * elements does not match the return value of getColumnHeaders, the headers
	 * will have standard width
	 */
	protected int[] getColumnBoundsPercentages() {
		return null;
	}

	/**
	 * Subclasses may override this method to specify another display column
	 * when using table combo. Defaults to 0
	 */
	protected int getDisplayColumn() {
		return 0;
	}

}