UpDownButtonBarPart.java

package bndtools.editor.common;

import java.util.ArrayList;
import java.util.List;

import org.bndtools.utils.collections.CollectionUtils;
import org.eclipse.jface.viewers.TableViewer;
import org.eclipse.swt.SWT;
import org.eclipse.swt.events.DisposeEvent;
import org.eclipse.swt.events.DisposeListener;
import org.eclipse.swt.events.SelectionAdapter;
import org.eclipse.swt.events.SelectionEvent;
import org.eclipse.swt.graphics.Image;
import org.eclipse.swt.widgets.Composite;
import org.eclipse.swt.widgets.Control;
import org.eclipse.swt.widgets.ToolBar;
import org.eclipse.swt.widgets.ToolItem;
import org.eclipse.ui.plugin.AbstractUIPlugin;

import bndtools.Plugin;

public class UpDownButtonBarPart {

    private final Image imgUp = AbstractUIPlugin.imageDescriptorFromPlugin(Plugin.PLUGIN_ID, "/icons/arrow_up.png").createImage();
    private final Image imgDown = AbstractUIPlugin.imageDescriptorFromPlugin(Plugin.PLUGIN_ID, "/icons/arrow_down.png").createImage();

    public static interface UpDownListener {
        void changed(List<Object> list);
    }

    private final TableViewer viewer;
    private final List<UpDownListener> listeners = new ArrayList<>();

    private ToolBar toolbar;

    private ToolItem btnUp;
    private ToolItem btnDown;

    public UpDownButtonBarPart(TableViewer viewer) {
        this.viewer = viewer;
    }

    public Control createControl(Composite parent, int style) {
        toolbar = new ToolBar(parent, style);

        btnUp = new ToolItem(toolbar, SWT.PUSH);
        btnUp.setImage(imgUp);
        btnUp.addSelectionListener(new SelectionAdapter() {
            @Override
            public void widgetSelected(SelectionEvent e) {
                doMoveUp();
            }
        });

        btnDown = new ToolItem(toolbar, SWT.PUSH);
        btnDown.setImage(imgDown);
        btnDown.addSelectionListener(new SelectionAdapter() {
            @Override
            public void widgetSelected(SelectionEvent e) {
                doMoveDown();
            }
        });

        toolbar.addDisposeListener(new DisposeListener() {
            @Override
            public void widgetDisposed(DisposeEvent de) {
                if (!imgUp.isDisposed())
                    imgUp.dispose();
                if (!imgDown.isDisposed())
                    imgDown.dispose();
            }
        });
        return toolbar;
    }

    public void setEnabledUp(boolean enabled) {
        btnUp.setEnabled(enabled);
    }

    public void setEnabledDown(boolean enabled) {
        btnDown.setEnabled(enabled);
    }

    private void doMoveUp() {
        int[] indexes = viewer.getTable().getSelectionIndices();

        @SuppressWarnings("unchecked")
        List<Object> list = (List<Object>) viewer.getInput();
        if (CollectionUtils.moveUp(list, indexes)) {
            viewer.setInput(list);
            for (UpDownListener l : listeners) {
                l.changed(list);
            }
        }
    }

    private void doMoveDown() {
        int[] indexes = viewer.getTable().getSelectionIndices();

        @SuppressWarnings("unchecked")
        List<Object> list = (List<Object>) viewer.getInput();
        if (CollectionUtils.moveDown(list, indexes)) {
            viewer.setInput(list);
            for (UpDownListener l : listeners) {
                l.changed(list);
            }
        }
    }

    public void addListener(UpDownListener l) {
        listeners.add(l);
    }

    public void removeListener(UpDownListener l) {
        listeners.remove(l);
    }
}