org.emftrace.quarc.ui.external.ColumnViewerSorter.java Source code

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Here is the source code for org.emftrace.quarc.ui.external.ColumnViewerSorter.java

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/*******************************************************************************
 * Copyright (c) 2006, 2007 Tom Schindl and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *     Tom Schindl - initial API and implementation
 *******************************************************************************/

package org.emftrace.quarc.ui.external;

import org.eclipse.jface.viewers.ColumnViewer;
import org.eclipse.jface.viewers.TableViewerColumn;
import org.eclipse.jface.viewers.Viewer;
import org.eclipse.jface.viewers.ViewerComparator;
import org.eclipse.swt.SWT;
import org.eclipse.swt.events.SelectionAdapter;
import org.eclipse.swt.events.SelectionEvent;

/**
 * A ViewerComparator for a JFace TableViewer
 * 
 * @author Tom Schindl <tom.schindl@bestsolution.at>
 * 
 * source: http://dev.eclipse.org/viewcvs/viewvc.cgi/org.eclipse.jface.snippets/Eclipse%20JFace%20Snippets/org/eclipse/jface/snippets/viewers/Snippet040TableViewerSorting.java?view=co
 */

public abstract class ColumnViewerSorter extends ViewerComparator {

    public static final int ASC = 1;

    public static final int NONE = 0;

    public static final int DESC = -1;

    private int sortDirection = 0;

    private TableViewerColumn column;

    private ColumnViewer viewer;

    /**
     * the constructor
     * 
     * @param viewer a ColumnViewer
     * @param column a TableViewerColumn of the specified ColumnViewer
     */
    public ColumnViewerSorter(ColumnViewer viewer, TableViewerColumn column) {
        this.column = column;
        this.viewer = viewer;
        this.column.getColumn().addSelectionListener(new SelectionAdapter() {

            public void widgetSelected(SelectionEvent e) {
                if (ColumnViewerSorter.this.viewer.getComparator() != null) {
                    if (ColumnViewerSorter.this.viewer.getComparator() == ColumnViewerSorter.this) {
                        int tdirection = ColumnViewerSorter.this.sortDirection;

                        if (tdirection == ASC) {
                            setSorter(ColumnViewerSorter.this, DESC);
                        } else if (tdirection == DESC) {
                            setSorter(ColumnViewerSorter.this, NONE);
                        }
                    } else {
                        setSorter(ColumnViewerSorter.this, ASC);
                    }
                } else {
                    setSorter(ColumnViewerSorter.this, ASC);
                }
            }
        });
    }

    /**
     * sets a Sorter and sort direction
     * @param sorter a ColumnViewerSorter
     * @param direction the sort direction (-1 = descending, 0 = none, 1 = ascending)
     */
    public void setSorter(ColumnViewerSorter sorter, int direction) {
        if (direction == NONE) {
            column.getColumn().getParent().setSortColumn(null);
            column.getColumn().getParent().setSortDirection(SWT.NONE);
            viewer.setComparator(null);
        } else {
            column.getColumn().getParent().setSortColumn(column.getColumn());
            sorter.sortDirection = direction;

            if (direction == ASC) {
                column.getColumn().getParent().setSortDirection(SWT.DOWN);
            } else {
                column.getColumn().getParent().setSortDirection(SWT.UP);
            }

            if (viewer.getComparator() == sorter) {
                viewer.refresh();
            } else {
                viewer.setComparator(sorter);
            }

        }
    }

    /* (non-Javadoc)
     * @see org.eclipse.jface.viewers.ViewerComparator#compare(org.eclipse.jface.viewers.Viewer, java.lang.Object, java.lang.Object)
     */
    public int compare(Viewer viewer, Object e1, Object e2) {
        return sortDirection * doCompare(viewer, e1, e2);
    }

    /**
     * Implementation of the compare 
     * @param viewer a Viewer
     * @param e1 the 1st object to compare
     * @param e2 the 2nd object to compare
     * @return the result of the compare
     */
    protected abstract int doCompare(Viewer viewer, Object e1, Object e2);
}