core/plugins/org.eclipse.dltk.testing/src/org/eclipse/dltk/internal/testing/wizards/MethodStubsSelectionButtonGroup.java - dltk/org.eclipse.dltk.core - Gitiles

 /*******************************************************************************
  * Copyright (c) 2000, 2017 IBM Corporation and others.
  * This program and the accompanying materials are made available under the
  * terms of the Eclipse Public License v. 2.0 which is available at
  * http://www.eclipse.org/legal/epl-2.0.
  *
  * SPDX-License-Identifier: EPL-2.0
  *
  * Contributors:
  *     IBM Corporation - initial API and implementation
  *******************************************************************************/
 package org.eclipse.dltk.internal.testing.wizards;

 import org.eclipse.core.runtime.Assert;
 import org.eclipse.dltk.internal.testing.util.LayoutUtil;
 import org.eclipse.swt.SWT;
 import org.eclipse.swt.events.SelectionEvent;
 import org.eclipse.swt.events.SelectionListener;
 import org.eclipse.swt.layout.GridData;
 import org.eclipse.swt.layout.GridLayout;
 import org.eclipse.swt.widgets.Button;
 import org.eclipse.swt.widgets.Composite;
 import org.eclipse.swt.widgets.Control;
 import org.eclipse.swt.widgets.Display;
 import org.eclipse.swt.widgets.Group;
 import org.eclipse.swt.widgets.Label;

 /**
  * A group of controls used in the JUnit TestCase and TestSuite wizards for
  * selecting method stubs to create.
  */
 public class MethodStubsSelectionButtonGroup {

 	private Label fLabel;
 	protected String fLabelText;

 	private SelectionButtonGroupListener fGroupListener;

 	private boolean fEnabled;

 	private Composite fButtonComposite;

 	private Button[] fButtons;
 	private String[] fButtonNames;
 	private boolean[] fButtonsSelected;
 	private boolean[] fButtonsEnabled;

 	private int fGroupBorderStyle;
 	private int fGroupNumberOfColumns;
 	private int fButtonsStyle;

 	public interface SelectionButtonGroupListener {
 		/**
 		 * The dialog field has changed.
 		 *
 		 * @param field
 		 *            The changed dialog field
 		 */
 		void groupChanged(MethodStubsSelectionButtonGroup field);
 	}

 	/**
 	 * Creates a group without border.
 	 */
 	public MethodStubsSelectionButtonGroup(int buttonsStyle,
 			String[] buttonNames, int nColumns) {
 		this(buttonsStyle, buttonNames, nColumns, SWT.NONE);
 	}

 	/**
 	 * Creates a group with border (label in border). Accepted button styles
 	 * are: SWT.RADIO, SWT.CHECK, SWT.TOGGLE For border styles see
 	 * <code>Group</code>
 	 */
 	public MethodStubsSelectionButtonGroup(int buttonsStyle,
 			String[] buttonNames, int nColumns, int borderStyle) {
 		fEnabled = true;
 		fLabel = null;
 		fLabelText = ""; //$NON-NLS-1$

 		Assert.isTrue(buttonsStyle == SWT.RADIO || buttonsStyle == SWT.CHECK
 				|| buttonsStyle == SWT.TOGGLE);
 		fButtonNames = buttonNames;

 		int nButtons = buttonNames.length;
 		fButtonsSelected = new boolean[nButtons];
 		fButtonsEnabled = new boolean[nButtons];
 		for (int i = 0; i < nButtons; i++) {
 			fButtonsSelected[i] = false;
 			fButtonsEnabled[i] = true;
 		}

 		if (buttonsStyle == SWT.RADIO) {
 			fButtonsSelected[0] = true;
 		}

 		fGroupBorderStyle = borderStyle;
 		fGroupNumberOfColumns = (nColumns <= 0) ? nButtons : nColumns;

 		fButtonsStyle = buttonsStyle;
 	}

 	/*
 	 * @see DialogField#doFillIntoGrid
 	 */
 	public Control[] doFillIntoGrid(Composite parent, int nColumns) {
 		assertEnoughColumns(nColumns);

 		if (fGroupBorderStyle == SWT.NONE) {
 			Label label = getLabelControl(parent);
 			label.setLayoutData(gridDataForLabel(1));

 			Composite buttonsgroup = getSelectionButtonsGroup(parent);
 			GridData gd = new GridData();
 			gd.horizontalSpan = nColumns - 1;
 			buttonsgroup.setLayoutData(gd);
 			return new Control[] { label, buttonsgroup };
 		} else {
 			Composite buttonsgroup = getSelectionButtonsGroup(parent);
 			GridData gd = new GridData();
 			gd.horizontalSpan = nColumns;
 			buttonsgroup.setLayoutData(gd);
 			return new Control[] { buttonsgroup };
 		}
 	}

 	/*
 	 * @see DialogField#doFillIntoGrid
 	 */
 	public int getNumberOfControls() {
 		return (fGroupBorderStyle == SWT.NONE) ? 2 : 1;
 	}

 	private Button createSelectionButton(int index, Composite group,
 			SelectionListener listener) {
 		Button button = new Button(group, fButtonsStyle | SWT.LEFT);
 		button.setFont(group.getFont());
 		button.setText(fButtonNames[index]);
 		button.setEnabled(isEnabled() && isEnabled(index));
 		button.setSelection(isSelected(index));
 		button.addSelectionListener(listener);
 		return button;
 	}

 	/**
 	 * Returns the group widget. When called the first time, the widget will be
 	 * created.
 	 *
 	 * @param parent
 	 *            composite when called the first time, or <code>null</code>
 	 *            after.
 	 */
 	public Composite getSelectionButtonsGroup(Composite parent) {
 		if (fButtonComposite == null) {
 			assertCompositeNotNull(parent);

 			GridLayout layout = new GridLayout();
 			// layout.makeColumnsEqualWidth= true;
 			layout.numColumns = fGroupNumberOfColumns;

 			if (fGroupBorderStyle != SWT.NONE) {
 				Group group = new Group(parent, fGroupBorderStyle);
 				if (fLabelText != null && fLabelText.length() > 0) {
 					group.setText(fLabelText);
 				}
 				fButtonComposite = group;
 			} else {
 				fButtonComposite = new Composite(parent, SWT.NULL);
 				layout.marginHeight = 0;
 				layout.marginWidth = 0;
 			}
 			fButtonComposite.setLayout(layout);

 			SelectionListener listener = new SelectionListener() {
 				@Override
 				public void widgetDefaultSelected(SelectionEvent e) {
 					doWidgetSelected(e);
 				}

 				@Override
 				public void widgetSelected(SelectionEvent e) {
 					doWidgetSelected(e);
 				}
 			};
 			int nButtons = fButtonNames.length;
 			fButtons = new Button[nButtons];

 			for (int i = 0; i < nButtons; i++) {
 				fButtons[i] = createSelectionButton(i, fButtonComposite,
 						listener);
 			}
 			int nRows = nButtons / fGroupNumberOfColumns;
 			int nFillElements = nRows * fGroupNumberOfColumns - nButtons;
 			for (int i = 0; i < nFillElements; i++) {
 				createEmptySpace(fButtonComposite);
 			}
 			setSelectionGroupListener(field -> field.setEnabled(1,
 					isEnabled() && field.isSelected(0)));
 		}
 		return fButtonComposite;
 	}

 	/**
 	 * Returns a button from the group or <code>null</code> if not yet created.
 	 */
 	public Button getSelectionButton(int index) {
 		if (index >= 0 && index < fButtons.length) {
 			return fButtons[index];
 		}
 		return null;
 	}

 	private void doWidgetSelected(SelectionEvent e) {
 		Button button = (Button) e.widget;
 		for (int i = 0; i < fButtons.length; i++) {
 			if (fButtons[i] == button) {
 				fButtonsSelected[i] = button.getSelection();
 				dialogFieldChanged();
 				return;
 			}
 		}
 	}

 	/**
 	 * Returns the selection state of a button contained in the group.
 	 *
 	 * @param index
 	 *            of the button
 	 */
 	public boolean isSelected(int index) {
 		if (index >= 0 && index < fButtonsSelected.length) {
 			return fButtonsSelected[index] && fButtonsEnabled[index];
 		}
 		return false;
 	}

 	/**
 	 * Sets the selection state of a button contained in the group.
 	 */
 	public void setSelection(int index, boolean selected) {
 		if (index >= 0 && index < fButtonsSelected.length) {
 			if (fButtonsSelected[index] != selected) {
 				fButtonsSelected[index] = selected;
 				if (fButtons != null) {
 					Button button = fButtons[index];
 					if (isOkToUse(button) && button.isEnabled()) {
 						button.setSelection(selected);
 					}
 				}
 			}
 		}
 	}

 	/**
 	 * Returns the enabled state of a button contained in the group.
 	 *
 	 * @param index
 	 *            of the button
 	 */
 	public boolean isEnabled(int index) {
 		if (index >= 0 && index < fButtonsEnabled.length) {
 			return fButtonsEnabled[index];
 		}
 		return false;
 	}

 	/**
 	 * Sets the selection state of a button contained in the group.
 	 */
 	public void setEnabled(int index, boolean enabled) {
 		if (index >= 0 && index < fButtonsEnabled.length) {
 			if (fButtonsEnabled[index] != enabled) {
 				fButtonsEnabled[index] = enabled;
 				if (fButtons != null) {
 					Button button = fButtons[index];
 					if (isOkToUse(button)) {
 						button.setEnabled(enabled);
 						if (!enabled) {
 							button.setSelection(false);
 						} else {
 							button.setSelection(fButtonsSelected[index]);
 						}
 					}
 				}
 			}
 		}
 	}

 	protected void updateEnableState() {
 		if (fLabel != null) {
 			fLabel.setEnabled(fEnabled);
 		}
 		if (fButtons != null) {
 			boolean enabled = isEnabled();
 			for (int i = 0; i < fButtons.length; i++) {
 				Button button = fButtons[i];
 				if (isOkToUse(button)) {
 					button.setEnabled(enabled && fButtonsEnabled[i]);
 				}
 			}
 		}
 	}

 	/**
 	 * Sets the label of the dialog field.
 	 */
 	public void setLabelText(String labeltext) {
 		fLabelText = labeltext;
 	}

 	/**
 	 * Defines the listener for this dialog field.
 	 */
 	public final void setSelectionGroupListener(
 			SelectionButtonGroupListener listener) {
 		fGroupListener = listener;
 	}

 	/**
 	 * A dialog field has changed.
 	 */
 	public void dialogFieldChanged() {
 		if (fGroupListener != null) {
 			fGroupListener.groupChanged(this);
 		}
 	}

 	/**
 	 * Tries to set the focus to the dialog field. Returns <code>true</code> if
 	 * the dialog field can take focus. To be re-implemented by dialog field
 	 * implementors.
 	 */
 	public boolean setFocus() {
 		return false;
 	}

 	/**
 	 * Posts <code>setFocus</code> to the display event queue.
 	 */
 	public void postSetFocusOnDialogField(Display display) {
 		if (display != null) {
 			display.asyncExec(() -> setFocus());
 		}
 	}

 	protected static GridData gridDataForLabel(int span) {
 		GridData gd = new GridData();
 		gd.horizontalSpan = span;
 		return gd;
 	}

 	/**
 	 * Creates or returns the created label widget.
 	 *
 	 * @param parent
 	 *            The parent composite or <code>null</code> if the widget has
 	 *            already been created.
 	 */
 	public Label getLabelControl(Composite parent) {
 		if (fLabel == null) {
 			assertCompositeNotNull(parent);

 			fLabel = new Label(parent, SWT.LEFT | SWT.WRAP);
 			fLabel.setFont(parent.getFont());
 			fLabel.setEnabled(fEnabled);
 			if (fLabelText != null && !"".equals(fLabelText)) { //$NON-NLS-1$
 				fLabel.setText(fLabelText);
 			} else {
 				// XXX: to avoid a 16 pixel wide empty label - revisit
 				fLabel.setText("."); //$NON-NLS-1$
 				fLabel.setVisible(false);
 			}
 		}
 		return fLabel;
 	}

 	/**
 	 * Creates a spacer control.
 	 *
 	 * @param parent
 	 *            The parent composite
 	 */
 	public static Control createEmptySpace(Composite parent) {
 		return createEmptySpace(parent, 1);
 	}

 	/**
 	 * Creates a spacer control with the given span. The composite is assumed to
 	 * have <code>MGridLayout</code> as layout.
 	 *
 	 * @param parent
 	 *            The parent composite
 	 */
 	public static Control createEmptySpace(Composite parent, int span) {
 		return LayoutUtil.createEmptySpace(parent, span);
 	}

 	/**
 	 * Tests is the control is not <code>null</code> and not disposed.
 	 */
 	protected final boolean isOkToUse(Control control) {
 		return (control != null) && !(control.isDisposed());
 	}

 	// --------- enable / disable management

 	/**
 	 * Sets the enable state of the dialog field.
 	 */
 	public final void setEnabled(boolean enabled) {
 		if (enabled != fEnabled) {
 			fEnabled = enabled;
 			updateEnableState();
 		}
 	}

 	/**
 	 * Gets the enable state of the dialog field.
 	 */
 	public final boolean isEnabled() {
 		return fEnabled;
 	}

 	protected final void assertCompositeNotNull(Composite comp) {
 		Assert.isNotNull(comp,
 				"uncreated control requested with composite null"); //$NON-NLS-1$
 	}

 	protected final void assertEnoughColumns(int nColumns) {
 		Assert.isTrue(nColumns >= getNumberOfControls(),
 				"given number of columns is too small"); //$NON-NLS-1$
 	}
 }
	/*******************************************************************************
	* Copyright (c) 2000, 2017 IBM Corporation and others.
	* This program and the accompanying materials are made available under the
	* terms of the Eclipse Public License v. 2.0 which is available at
	* http://www.eclipse.org/legal/epl-2.0.
	*
	* SPDX-License-Identifier: EPL-2.0
	*
	* Contributors:
	* IBM Corporation - initial API and implementation
	*******************************************************************************/
	package org.eclipse.dltk.internal.testing.wizards;

	import org.eclipse.core.runtime.Assert;
	import org.eclipse.dltk.internal.testing.util.LayoutUtil;
	import org.eclipse.swt.SWT;
	import org.eclipse.swt.events.SelectionEvent;
	import org.eclipse.swt.events.SelectionListener;
	import org.eclipse.swt.layout.GridData;
	import org.eclipse.swt.layout.GridLayout;
	import org.eclipse.swt.widgets.Button;
	import org.eclipse.swt.widgets.Composite;
	import org.eclipse.swt.widgets.Control;
	import org.eclipse.swt.widgets.Display;
	import org.eclipse.swt.widgets.Group;
	import org.eclipse.swt.widgets.Label;

	/**
	* A group of controls used in the JUnit TestCase and TestSuite wizards for
	* selecting method stubs to create.
	*/
	public class MethodStubsSelectionButtonGroup {

	private Label fLabel;
	protected String fLabelText;

	private SelectionButtonGroupListener fGroupListener;

	private boolean fEnabled;

	private Composite fButtonComposite;

	private Button[] fButtons;
	private String[] fButtonNames;
	private boolean[] fButtonsSelected;
	private boolean[] fButtonsEnabled;

	private int fGroupBorderStyle;
	private int fGroupNumberOfColumns;
	private int fButtonsStyle;

	public interface SelectionButtonGroupListener {
	/**
	* The dialog field has changed.
	*
	* @param field
	* The changed dialog field
	*/
	void groupChanged(MethodStubsSelectionButtonGroup field);
	}

	/**
	* Creates a group without border.
	*/
	public MethodStubsSelectionButtonGroup(int buttonsStyle,
	String[] buttonNames, int nColumns) {
	this(buttonsStyle, buttonNames, nColumns, SWT.NONE);
	}

	/**
	* Creates a group with border (label in border). Accepted button styles
	* are: SWT.RADIO, SWT.CHECK, SWT.TOGGLE For border styles see
	* <code>Group</code>
	*/
	public MethodStubsSelectionButtonGroup(int buttonsStyle,
	String[] buttonNames, int nColumns, int borderStyle) {
	fEnabled = true;
	fLabel = null;
	fLabelText = ""; //$NON-NLS-1$

	Assert.isTrue(buttonsStyle == SWT.RADIO \|\| buttonsStyle == SWT.CHECK
	\|\| buttonsStyle == SWT.TOGGLE);
	fButtonNames = buttonNames;

	int nButtons = buttonNames.length;
	fButtonsSelected = new boolean[nButtons];
	fButtonsEnabled = new boolean[nButtons];
	for (int i = 0; i < nButtons; i++) {
	fButtonsSelected[i] = false;
	fButtonsEnabled[i] = true;
	}

	if (buttonsStyle == SWT.RADIO) {
	fButtonsSelected[0] = true;
	}

	fGroupBorderStyle = borderStyle;
	fGroupNumberOfColumns = (nColumns <= 0) ? nButtons : nColumns;

	fButtonsStyle = buttonsStyle;
	}

	/*
	* @see DialogField#doFillIntoGrid
	*/
	public Control[] doFillIntoGrid(Composite parent, int nColumns) {
	assertEnoughColumns(nColumns);

	if (fGroupBorderStyle == SWT.NONE) {
	Label label = getLabelControl(parent);
	label.setLayoutData(gridDataForLabel(1));

	Composite buttonsgroup = getSelectionButtonsGroup(parent);
	GridData gd = new GridData();
	gd.horizontalSpan = nColumns - 1;
	buttonsgroup.setLayoutData(gd);
	return new Control[] { label, buttonsgroup };
	} else {
	Composite buttonsgroup = getSelectionButtonsGroup(parent);
	GridData gd = new GridData();
	gd.horizontalSpan = nColumns;
	buttonsgroup.setLayoutData(gd);
	return new Control[] { buttonsgroup };
	}
	}

	/*
	* @see DialogField#doFillIntoGrid
	*/
	public int getNumberOfControls() {
	return (fGroupBorderStyle == SWT.NONE) ? 2 : 1;
	}

	private Button createSelectionButton(int index, Composite group,
	SelectionListener listener) {
	Button button = new Button(group, fButtonsStyle \| SWT.LEFT);
	button.setFont(group.getFont());
	button.setText(fButtonNames[index]);
	button.setEnabled(isEnabled() && isEnabled(index));
	button.setSelection(isSelected(index));
	button.addSelectionListener(listener);
	return button;
	}

	/**
	* Returns the group widget. When called the first time, the widget will be
	* created.
	*
	* @param parent
	* composite when called the first time, or <code>null</code>
	* after.
	*/
	public Composite getSelectionButtonsGroup(Composite parent) {
	if (fButtonComposite == null) {
	assertCompositeNotNull(parent);

	GridLayout layout = new GridLayout();
	// layout.makeColumnsEqualWidth= true;
	layout.numColumns = fGroupNumberOfColumns;

	if (fGroupBorderStyle != SWT.NONE) {
	Group group = new Group(parent, fGroupBorderStyle);
	if (fLabelText != null && fLabelText.length() > 0) {
	group.setText(fLabelText);
	}
	fButtonComposite = group;
	} else {
	fButtonComposite = new Composite(parent, SWT.NULL);
	layout.marginHeight = 0;
	layout.marginWidth = 0;
	}
	fButtonComposite.setLayout(layout);

	SelectionListener listener = new SelectionListener() {
	@Override
	public void widgetDefaultSelected(SelectionEvent e) {
	doWidgetSelected(e);
	}

	@Override
	public void widgetSelected(SelectionEvent e) {
	doWidgetSelected(e);
	}
	};
	int nButtons = fButtonNames.length;
	fButtons = new Button[nButtons];

	for (int i = 0; i < nButtons; i++) {
	fButtons[i] = createSelectionButton(i, fButtonComposite,
	listener);
	}
	int nRows = nButtons / fGroupNumberOfColumns;
	int nFillElements = nRows * fGroupNumberOfColumns - nButtons;
	for (int i = 0; i < nFillElements; i++) {
	createEmptySpace(fButtonComposite);
	}
	setSelectionGroupListener(field -> field.setEnabled(1,
	isEnabled() && field.isSelected(0)));
	}
	return fButtonComposite;
	}

	/**
	* Returns a button from the group or <code>null</code> if not yet created.
	*/
	public Button getSelectionButton(int index) {
	if (index >= 0 && index < fButtons.length) {
	return fButtons[index];
	}
	return null;
	}

	private void doWidgetSelected(SelectionEvent e) {
	Button button = (Button) e.widget;
	for (int i = 0; i < fButtons.length; i++) {
	if (fButtons[i] == button) {
	fButtonsSelected[i] = button.getSelection();
	dialogFieldChanged();
	return;
	}
	}
	}

	/**
	* Returns the selection state of a button contained in the group.
	*
	* @param index
	* of the button
	*/
	public boolean isSelected(int index) {
	if (index >= 0 && index < fButtonsSelected.length) {
	return fButtonsSelected[index] && fButtonsEnabled[index];
	}
	return false;
	}

	/**
	* Sets the selection state of a button contained in the group.
	*/
	public void setSelection(int index, boolean selected) {
	if (index >= 0 && index < fButtonsSelected.length) {
	if (fButtonsSelected[index] != selected) {
	fButtonsSelected[index] = selected;
	if (fButtons != null) {
	Button button = fButtons[index];
	if (isOkToUse(button) && button.isEnabled()) {
	button.setSelection(selected);
	}
	}
	}
	}
	}

	/**
	* Returns the enabled state of a button contained in the group.
	*
	* @param index
	* of the button
	*/
	public boolean isEnabled(int index) {
	if (index >= 0 && index < fButtonsEnabled.length) {
	return fButtonsEnabled[index];
	}
	return false;
	}

	/**
	* Sets the selection state of a button contained in the group.
	*/
	public void setEnabled(int index, boolean enabled) {
	if (index >= 0 && index < fButtonsEnabled.length) {
	if (fButtonsEnabled[index] != enabled) {
	fButtonsEnabled[index] = enabled;
	if (fButtons != null) {
	Button button = fButtons[index];
	if (isOkToUse(button)) {
	button.setEnabled(enabled);
	if (!enabled) {
	button.setSelection(false);
	} else {
	button.setSelection(fButtonsSelected[index]);
	}
	}
	}
	}
	}
	}

	protected void updateEnableState() {
	if (fLabel != null) {
	fLabel.setEnabled(fEnabled);
	}
	if (fButtons != null) {
	boolean enabled = isEnabled();
	for (int i = 0; i < fButtons.length; i++) {
	Button button = fButtons[i];
	if (isOkToUse(button)) {
	button.setEnabled(enabled && fButtonsEnabled[i]);
	}
	}
	}
	}

	/**
	* Sets the label of the dialog field.
	*/
	public void setLabelText(String labeltext) {
	fLabelText = labeltext;
	}

	/**
	* Defines the listener for this dialog field.
	*/
	public final void setSelectionGroupListener(
	SelectionButtonGroupListener listener) {
	fGroupListener = listener;
	}

	/**
	* A dialog field has changed.
	*/
	public void dialogFieldChanged() {
	if (fGroupListener != null) {
	fGroupListener.groupChanged(this);
	}
	}

	/**
	* Tries to set the focus to the dialog field. Returns <code>true</code> if
	* the dialog field can take focus. To be re-implemented by dialog field
	* implementors.
	*/
	public boolean setFocus() {
	return false;
	}

	/**
	* Posts <code>setFocus</code> to the display event queue.
	*/
	public void postSetFocusOnDialogField(Display display) {
	if (display != null) {
	display.asyncExec(() -> setFocus());
	}
	}

	protected static GridData gridDataForLabel(int span) {
	GridData gd = new GridData();
	gd.horizontalSpan = span;
	return gd;
	}

	/**
	* Creates or returns the created label widget.
	*
	* @param parent
	* The parent composite or <code>null</code> if the widget has
	* already been created.
	*/
	public Label getLabelControl(Composite parent) {
	if (fLabel == null) {
	assertCompositeNotNull(parent);

	fLabel = new Label(parent, SWT.LEFT \| SWT.WRAP);
	fLabel.setFont(parent.getFont());
	fLabel.setEnabled(fEnabled);
	if (fLabelText != null && !"".equals(fLabelText)) { //$NON-NLS-1$
	fLabel.setText(fLabelText);
	} else {
	// XXX: to avoid a 16 pixel wide empty label - revisit
	fLabel.setText("."); //$NON-NLS-1$
	fLabel.setVisible(false);
	}
	}
	return fLabel;
	}

	/**
	* Creates a spacer control.
	*
	* @param parent
	* The parent composite
	*/
	public static Control createEmptySpace(Composite parent) {
	return createEmptySpace(parent, 1);
	}

	/**
	* Creates a spacer control with the given span. The composite is assumed to
	* have <code>MGridLayout</code> as layout.
	*
	* @param parent
	* The parent composite
	*/
	public static Control createEmptySpace(Composite parent, int span) {
	return LayoutUtil.createEmptySpace(parent, span);
	}

	/**
	* Tests is the control is not <code>null</code> and not disposed.
	*/
	protected final boolean isOkToUse(Control control) {
	return (control != null) && !(control.isDisposed());
	}

	// --------- enable / disable management

	/**
	* Sets the enable state of the dialog field.
	*/
	public final void setEnabled(boolean enabled) {
	if (enabled != fEnabled) {
	fEnabled = enabled;
	updateEnableState();
	}
	}

	/**
	* Gets the enable state of the dialog field.
	*/
	public final boolean isEnabled() {
	return fEnabled;
	}

	protected final void assertCompositeNotNull(Composite comp) {
	Assert.isNotNull(comp,
	"uncreated control requested with composite null"); //$NON-NLS-1$
	}

	protected final void assertEnoughColumns(int nColumns) {
	Assert.isTrue(nColumns >= getNumberOfControls(),
	"given number of columns is too small"); //$NON-NLS-1$
	}
	}