Remove button to remove itself

This article describes how to implement a table with SWT that holds several rows. Each row contains a button to remove this row.

This is tricky for two reasons:

1. How to get a button into a table cell
2. How let the button remove itself

The first part is described in this example. The trick is to use a TableEditor and put the button into it.
The problem with the second is that you want to execute a method on an object that removes itself. Therefor you have to delegate the removing.
All this together is shown in this piece of code:

import org.eclipse.swt.SWT;
import org.eclipse.swt.custom.TableEditor;
import org.eclipse.swt.events.SelectionAdapter;
import org.eclipse.swt.events.SelectionEvent;
import org.eclipse.swt.graphics.Point;
import org.eclipse.swt.layout.GridData;
import org.eclipse.swt.layout.GridLayout;
import org.eclipse.swt.widgets.Button;
import org.eclipse.swt.widgets.Display;
import org.eclipse.swt.widgets.Event;
import org.eclipse.swt.widgets.Label;
import org.eclipse.swt.widgets.Listener;
import org.eclipse.swt.widgets.Shell;
import org.eclipse.swt.widgets.Table;
import org.eclipse.swt.widgets.TableColumn;
import org.eclipse.swt.widgets.TableItem;
public class TableTest {
  private Shell sShell = null;
  private Table table = null;
  private Button button = null;
  /** Main method */
  public static void main (String[] args){
    new TableTest().createSShell();
  }
  /**
   * This method initializes sShell
   */
  private void createSShell() {
    GridData gridData = new GridData();
    gridData.horizontalSpan = 2;
    GridLayout gridLayout = new GridLayout();
    gridLayout.numColumns = 2;
    sShell = new Shell();
    sShell.setText("Shell");
    sShell.setLayout(gridLayout);
    sShell.setSize(new Point(300, 200));
    table = new Table(sShell, SWT.BORDER | SWT.V_SCROLL | SWT.H_SCROLL);
    table.setHeaderVisible(true);
    new Label(sShell, SWT.NONE);
    button = new Button(sShell, SWT.NONE);
    button.setText("Add");
    button.addSelectionListener(new SelectionAdapter(){
      public void widgetSelected(SelectionEvent e) {
        addRow();
      }
    });	
    String[] titles = { "Class Name", "Class package", "Generation Type" ,""}; //$NON-NLS-1$
    GridData gridData2 = new GridData(GridData.VERTICAL_ALIGN_END);
    gridData2.horizontalSpan = 2;
    gridData2.horizontalAlignment = GridData.FILL;
    gridData2.grabExcessHorizontalSpace=true;
    gridData2.grabExcessVerticalSpace=true;
    gridData2.heightHint=300;
    table.setLayoutData(gridData2);
    table.setLinesVisible(true);
    for (int loopIndex = 0; loopIndex < titles.length; loopIndex++) {
      TableColumn column = new TableColumn(table, SWT.NULL);
      column.setText(titles[loopIndex]);
    }
    for (int loopIndex = 0; loopIndex < titles.length; loopIndex++) {
      table.getColumn(loopIndex).pack();
    }
    // resize the row height using a MeasureItem listener
    table.addListener(SWT.MeasureItem, new Listener() {
      public void handleEvent(Event event) {
        // height cannot be per row so simply set
        event.height = 40;
      }
    });
  }
  /**
   * 
   */
  private void addRow() {
    TableItem item = new TableItem(table, SWT.NONE);
    item.setText(new String[] {"Class name","package.name","Type"});
    final TableEditor editor = new TableEditor(table);
    btnRemove = new Button(table,SWT.PUSH);
    btnRemove.setData(new Integer(table.getItemCount()-1));
    btnRemove.setText("remove");
    btnRemove.addSelectionListener(new SelectionAdapter(){
      @Override
      public void widgetSelected(SelectionEvent e) {
        final Display display = sShell.getDisplay();
        display.asyncExec(new Runnable(){
          public void run(){
            Button btn = (Button) editor.getEditor();
            btn.dispose();
            table.remove(0);
          }
        });
      }	
    });
    editor.grabHorizontal = true;
    editor.setEditor(btnRemove, item, 3);
  }
}

Known issue with the code above: If you have two rows and hit the remove button of the second, the second row and the remove button of the first is removed.