ComboBoxCellEditorSnippet.java

public static ComboBoxViewerCellEditor criarColumnComboBox(TableViewerColumn tvc, final Class<?> clazz, final String property, Object[] values, String titulo) {
	return criarColunaComboBoxEditable(tvc, clazz, property, values, titulo, new ColumnLabelProvider() {
		@Override
		public String getText(Object element) {
			if (clazz.isInstance(element)) {
				return element.toString();
			} else {
				Object value = ReflectionHelper.getValue(element, property);
				return value == null ? StringUtils.EMPTY : value.toString();
			}
		}
	});
}

private static ComboBoxViewerCellEditor criarColunaComboBoxEditable(TableViewerColumn tvc, final Class<?> clazz, final String property, Object[] values, String titulo, ColumnLabelProvider labelProvider) {
	tvc.setLabelProvider(labelProvider);

	ComboBoxViewerCellEditor comboCellEditor = new ComboBoxViewerCellEditor((Composite) tvc.getViewer().getControl(), SWT.READ_ONLY);
	comboCellEditor.setContentProvider(ArrayContentProvider.getInstance());
	comboCellEditor.setInput(values);
	comboCellEditor.setLabelProvider(labelProvider);

	CustomAbstractEditingSupport<ItemDocumentoFiscal> editingSupport = new CustomAbstractEditingSupport<ItemDocumentoFiscal>((TableViewer) tvc.getViewer(), comboCellEditor) {
		@Override
		protected void doSetValue(ItemDocumentoFiscal element, Object value) {
			if (clazz.isInstance(value))
				ReflectionHelper.setValue(element, property, value);
		}

		@Override
		protected Object doGetValue(ItemDocumentoFiscal element) {
		  // Esse ReflectionHelper.getValue simplesmente busca o valor de uma propriedade de um determinado objeto utilizando reflexão
			Object value = ReflectionHelper.getValue(element, property);
			return value == null ? "" : value.toString();
		}
	};
	tvc.setEditingSupport(editingSupport);

	TableColumn tc = tvc.getColumn();
	tc.setText(titulo);

	return comboCellEditor;
}