org.eclipse.osbp.preferences.ui.page/src/org/eclipse/osbp/preferences/ui/component/AddRemoveListFieldEditor.java - osbp/org.eclipse.osbp.preferences - Git at Google

 /**
  *
  * Copyright (c) 2011, 2016 - Loetz GmbH&Co.KG (69115 Heidelberg, Germany)
  *
  * 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:
  * Christophe Loetz (Loetz GmbH&Co.KG) - initial implementation
  */
 package org.eclipse.osbp.preferences.ui.component;

 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Set;
 import java.util.StringTokenizer;
 import java.util.TreeSet;

 import org.eclipse.jface.dialogs.IDialogConstants;
 import org.eclipse.jface.preference.FieldEditor;
 import org.eclipse.swt.SWT;
 import org.eclipse.swt.custom.CLabel;
 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.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.Label;
 import org.eclipse.swt.widgets.List;

 /**
  * A field editor for displaying and storing a list of strings.
  * Buttons are provided for adding items to the list and removing
  * items from the list.
  */
 public class AddRemoveListFieldEditor extends FieldEditor {
 	private static final String TO_LEFT_SIGN = "<"; //"\u0171";
 	private static final String TO_RIGHT_SIGN = ">"; //"\u0187";

 	private static final String DEFAULT_SELECT_LABEL = TO_LEFT_SIGN+" select "+TO_LEFT_SIGN;
 	private static final String DEFAULT_DESELECT_LABEL = TO_RIGHT_SIGN+" deselect "+TO_RIGHT_SIGN;
 	private static final String DEFAULT_SEPERATOR = ";";

 	private static final int VERTICAL_DIALOG_UNITS_PER_CHAR = 8;
 	private static final int HORIZONTAL_DIALOG_UNITS_PER_CHAR = 4;
 	private static final int LIST_HEIGHT_IN_CHARS = 10;
 	private static final int LIST_HEIGHT_IN_DLUS = LIST_HEIGHT_IN_CHARS * VERTICAL_DIALOG_UNITS_PER_CHAR;

 	// The top-level control for the field editor.
 	private Composite top;
 	// The list of selected tags.
 	private List selectedList;
 	// The list with available and not selected tags.
 	private List availableList;
 	// The button for adding the contents of
 	// the available list to the selected list.
 	private Button select;
 	// The button for removing the currently-selected list item.
 	private Button deselect;
 	// The string used to seperate list items
 	// in a single String representation.
 	private String seperator = DEFAULT_SEPERATOR;
     protected CLabel label;

 	private String[][]availableNamesAndValues;

 	public AddRemoveListFieldEditor(
 		String name,
 		String labelText,
 		String[][] availableNamesAndValues,
 		Composite parent) {
 			super(name, labelText, parent);
 			this.availableNamesAndValues = availableNamesAndValues;
 	}

 	public AddRemoveListFieldEditor(
 		String name,
 		String labelText,
 		String[][] availableNamesAndValues,
 		String selectButtonText,
 		String deselectButtonText,
 		Composite parent) {
 			this(name, labelText, availableNamesAndValues, parent);
 			setSelectButtonText(selectButtonText);
 			setDeselectButtonText(deselectButtonText);
 	}

 	public void setAvailableNamesAndValues(String[][] availableNamesAndValues) {
 		this.availableNamesAndValues = availableNamesAndValues;
 		refreshAvailableList();
 	}

 	/**
 	 * @see org.eclipse.jface.preference.FieldEditor#adjustForNumColumns(int)
 	 */
 	protected void adjustForNumColumns(int numColumns) {
 		((GridData)top.getLayoutData()).horizontalSpan = numColumns;
 	}

 	/**
 	 * @see org.eclipse.jface.preference.FieldEditor#doFillIntoGrid
 	 * (Composite, int)
 	 */
 	protected void doFillIntoGrid(Composite parent, int numColumns) {
 		top = parent;

 		int buttonWidth = convertHorizontalDLUsToPixels(top, IDialogConstants.BUTTON_WIDTH);
 		int buttonHeight = convertVerticalDLUsToPixels(top, IDialogConstants.BUTTON_HEIGHT);

 		GridData gd = new GridData(GridData.FILL_HORIZONTAL);
 		gd.horizontalSpan = numColumns;
 		top.setLayoutData(gd);

 		getLabelControl(top);
 		GridData labelData = new GridData();
 		labelData.horizontalSpan = numColumns;
 		label.setLayoutData(labelData);

 		Composite components = new Composite(top, SWT.NONE);

 		GridData componentsData = new GridData();
 		componentsData.horizontalSpan = numColumns;
 		componentsData.heightHint = buttonHeight * 10+10;
 		components.setLayoutData(componentsData);
 		//components.setBackground(new org.eclipse.swt.graphics.Color(components.getDisplay(), 255,255,255));
 		GridLayout componentsLayout = new GridLayout(3, false);
 		components.setLayout(componentsLayout);

 		selectedList = new List(components, SWT.BORDER | SWT.V_SCROLL);
 		GridData selectedData = new GridData();
 		selectedData.heightHint = buttonHeight * 10;
 		selectedList.setLayoutData(selectedData);
 		//selectedList.setBackground(new org.eclipse.swt.graphics.Color(components.getDisplay(), 255,0,0));

 		// Create a grid data that takes up the extra
 		// space in the dialog and spans both columns.
 		//*GridData selectedListData = new GridData(GridData.FILL_HORIZONTAL);
 		//*selectedListData.heightHint = convertVerticalDLUsToPixels(selectedList, LIST_HEIGHT_IN_DLUS);
 		//*selectedListData.horizontalSpan = numColumns;

 		//*selectedList.setLayoutData(selectedListData);
 		selectedList.addSelectionListener(new SelectionAdapter() {
 			public void widgetSelected(SelectionEvent e) {
 				selectedSelectionChanged();
 			}
 		});

 		// Create a composite for the add and remove
 		// buttons and the input text field.
 		Composite addRemoveGroup = new Composite(components, SWT.NONE);
 //		GridData addRemoveData = new GridData();
 //		addRemoveData.heightHint = buttonHeight * 10;
 //		addRemoveGroup.setLayoutData(addRemoveData);
 		//addRemoveGroup.setBackground(new org.eclipse.swt.graphics.Color(components.getDisplay(), 0,255,0));

 		//*GridData addRemoveData = new GridData(GridData.FILL_HORIZONTAL);
 		//*addRemoveData.horizontalSpan = numColumns;
 		//*addRemoveGroup.setLayoutData(addRemoveData);

 		GridLayout addRemoveLayout = new GridLayout();
 		addRemoveLayout.numColumns = numColumns;
 		addRemoveLayout.marginHeight = 0;
 		addRemoveLayout.marginWidth = 0;
 		addRemoveGroup.setLayout(addRemoveLayout);
 		addRemoveGroup.setSize(buttonWidth, buttonHeight*2);

 		// Create a composite for the add and remove buttons.
 		Composite buttonGroup = new Composite(addRemoveGroup, SWT.NONE);
 		//*buttonGroup.setLayoutData(new GridData());

 		GridLayout buttonLayout = new GridLayout();
 		buttonLayout.marginHeight = 0;
 		buttonLayout.marginWidth = 0;
 		buttonGroup.setLayout(buttonLayout);

 		// Create the remove button.
 		deselect = new Button(buttonGroup, SWT.NONE);
 		deselect.setEnabled(false);
 		deselect.setText(DEFAULT_DESELECT_LABEL);
 		deselect.addSelectionListener(new SelectionAdapter() {
 			public void widgetSelected(SelectionEvent e) {
 				deselect();
 				showDefaultHint();
 			}
 		});
 		GridData removeData = new GridData(GridData.FILL_HORIZONTAL);
 		removeData.heightHint = buttonHeight;
 		removeData.widthHint = buttonWidth;
 		deselect.setLayoutData(removeData);

 		// Create the add button.
 		select = new Button(buttonGroup, SWT.NONE);
 		select.setEnabled(false);
 		select.setText(DEFAULT_SELECT_LABEL);
 		select.addSelectionListener(new SelectionAdapter() {
 			public void widgetSelected(SelectionEvent e) {
 				select();
 				showDefaultHint();
 			}
 		});
 		GridData addData = new GridData(GridData.FILL_HORIZONTAL);
 		addData.heightHint = buttonHeight;
 		addData.widthHint = buttonWidth;
 		select.setLayoutData(addData);

 		// available list
 		availableList = new List(components, SWT.BORDER | SWT.V_SCROLL);
 		GridData availableData = new GridData();
 		availableData.heightHint = buttonHeight * 10;
 		availableList.setLayoutData(availableData);
 		//availableList.setBackground(new org.eclipse.swt.graphics.Color(components.getDisplay(), 0,0,255));

 		// Create a grid data that takes up the extra
 		// space in the dialog and spans both columns.
 		//*GridData availableListData = new GridData(GridData.FILL_HORIZONTAL);
 		//*availableListData.heightHint = convertVerticalDLUsToPixels(availableList, LIST_HEIGHT_IN_DLUS);
 		//*availableListData.horizontalSpan = numColumns;

 		//*availableList.setLayoutData(availableListData);
 		availableList.addSelectionListener(new SelectionAdapter() {
 			public void widgetSelected(SelectionEvent e) {
 				availableSelectionChanged();
 			}
 		});
 	}

 	protected void showDefaultHint() {
 		String defaults = getPreferenceStore().getDefaultString(getPreferenceName());
 		String selected = createListString(selectedList.getItems());
 		APreferencePage.showLabelDefaultHint(label, defaults.equals(selected));
 	}

 	@Override
     public Label getLabelControl(Composite parent) {
         if (label == null) {
             label = new CLabel(parent, SWT.LEFT | SWT.RIGHT_TO_LEFT);
             label.setFont(parent.getFont());
             String text = getLabelText();
             if (text != null) {
 				label.setText(text);
 			}
             label.addDisposeListener(new DisposeListener() {
                 @Override
 				public void widgetDisposed(DisposeEvent event) {
                     label = null;
                 }
             });
         } else {
             checkParent(label, parent);
         }
         return null;
     }

 	@Override
     public void setEnabled(boolean enabled, Composite parent) {
         label.setEnabled(enabled);
     }

 	/**
 	 * @see org.eclipse.jface.preference.FieldEditor#doLoad()
 	 */
 	protected void doLoad() {
 		String items = getPreferenceStore().getString(getPreferenceName());
 		setList(items);
 		showDefaultHint();
 	}

 	/**
 	 * @see org.eclipse.jface.preference.FieldEditor#doLoadDefault()
 	 */
 	protected void doLoadDefault() {
 		String items = getPreferenceStore().getDefaultString(getPreferenceName());
 		setList(items);
 		showDefaultHint();
 	}

 	// Parses the string into seperate list items and adds them to the list.
 	private void setList(String items) {
 		String[] itemArray = parseString(items);
 		selectedList.setItems(itemArray);
 	}

 	/**
 	 * @see org.eclipse.jface.preference.FieldEditor#doStore()
 	 */
 	protected void doStore() {
 		String s = createListString(selectedList.getItems());
 		if (s != null)
 			getPreferenceStore().setValue(getPreferenceName(), s);
 	}

 	/**
 	 * @see org.eclipse.jface.preference.FieldEditor#getNumberOfControls()
 	 */
 	public int getNumberOfControls() {
 		// The button composite and the text field.
 		return 2;
 	}

 	// Adds the string in the text field to the list.
 	private void select() {
 		Set<String> items = new TreeSet<String>();
 		items.addAll(Arrays.asList(selectedList.getItems()));
 		items.addAll(Arrays.asList(availableList.getSelection()));
 		selectedList.removeAll();
 		for	(String addItem : items) {
 			selectedList.add(addItem);
 		}
 		refreshAvailableList();
 	}

 	private void deselect() {
 		Set<String> items = new TreeSet<String>();
 		items.addAll(Arrays.asList(selectedList.getItems()));
 		items.removeAll(Arrays.asList(selectedList.getSelection()));
 		selectedList.removeAll();
 		for	(String addItem : items) {
 			selectedList.add(addItem);
 		}
 		refreshAvailableList();
 	}

 	private void refreshAvailableList() {
 		java.util.List<String> ignoreItems = Arrays.asList(selectedList.getItems());
 		availableList.removeAll();
 		for	(int idx = 0; idx < availableNamesAndValues.length; idx++) {
 			String addItem = availableNamesAndValues[idx][1];
 			if	((addItem != null) && !ignoreItems.contains(addItem)) {
 				availableList.add(addItem);
 			}
 		}
 		selectedList.deselectAll();
 		availableList.deselectAll();
 		select.setEnabled(false);
 		deselect.setEnabled(false);
 	}

 	/**
 	 *  Sets the label for the button that adds
 	 * the contents of the text field to the list.
 	 */
 	public void setSelectButtonText(String text) {
 		select.setText(text);
 	}

 	/**
 	 *  Sets the label for the button that removes
 	 * the selected item from the list.
 	 */
 	public void setDeselectButtonText(String text) {
 		deselect.setText(text);
 	}

 	/**
 	 * Sets the string that seperates items in the list when the
 	 * list is stored as a single String in the preference store.
 	 */
 	public void setSeperator(String seperator) {
 		this.seperator = seperator;
 	}

 	/**
 	 *  Creates the single String representation of the list
 	 * that is stored in the preference store.
 	 */
 	private String createListString(String[] items) {
 		StringBuffer path = new StringBuffer("");//$NON-NLS-1$
 		for (int i = 0; i < items.length; i++) {
 			if	(i > 0) {
 				path.append(seperator);
 			}
 			path.append(items[i]);
 		}
 		return path.toString();
 	}

 	/**
 	 *  Parses the single String representation of the list
 	 * into an array of list items.
 	 */
 	private String[] parseString(String stringList) {
 		StringTokenizer st =
 			new StringTokenizer(stringList, seperator); //$NON-NLS-1$
 		ArrayList v = new ArrayList();
 		while (st.hasMoreElements()) {
 			v.add(st.nextElement());
 		}
 		return (String[])v.toArray(new String[v.size()]);
 	}

 	// Sets the enablement of the remove button depending
 	// on the selection in the list.
 	private void selectedSelectionChanged() {
 		int index = selectedList.getSelectionIndex();
 		deselect.setEnabled(index >= 0);
 		availableList.deselectAll();
 		select.setEnabled(false);
 	}

 	// Sets the enablement of the remove button depending
 	// on the selection in the list.
 	private void availableSelectionChanged() {
 		int index = availableList.getSelectionIndex();
 		select.setEnabled(index >= 0);
 		selectedList.deselectAll();
 		deselect.setEnabled(false);
 	}
 }
	/**
	*
	* Copyright (c) 2011, 2016 - Loetz GmbH&Co.KG (69115 Heidelberg, Germany)
	*
	* 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:
	* Christophe Loetz (Loetz GmbH&Co.KG) - initial implementation
	*/
	package org.eclipse.osbp.preferences.ui.component;

	import java.util.ArrayList;
	import java.util.Arrays;
	import java.util.Set;
	import java.util.StringTokenizer;
	import java.util.TreeSet;

	import org.eclipse.jface.dialogs.IDialogConstants;
	import org.eclipse.jface.preference.FieldEditor;
	import org.eclipse.swt.SWT;
	import org.eclipse.swt.custom.CLabel;
	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.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.Label;
	import org.eclipse.swt.widgets.List;

	/**
	* A field editor for displaying and storing a list of strings.
	* Buttons are provided for adding items to the list and removing
	* items from the list.
	*/
	public class AddRemoveListFieldEditor extends FieldEditor {
	private static final String TO_LEFT_SIGN = "<"; //"\u0171";
	private static final String TO_RIGHT_SIGN = ">"; //"\u0187";

	private static final String DEFAULT_SELECT_LABEL = TO_LEFT_SIGN+" select "+TO_LEFT_SIGN;
	private static final String DEFAULT_DESELECT_LABEL = TO_RIGHT_SIGN+" deselect "+TO_RIGHT_SIGN;
	private static final String DEFAULT_SEPERATOR = ";";

	private static final int VERTICAL_DIALOG_UNITS_PER_CHAR = 8;
	private static final int HORIZONTAL_DIALOG_UNITS_PER_CHAR = 4;
	private static final int LIST_HEIGHT_IN_CHARS = 10;
	private static final int LIST_HEIGHT_IN_DLUS = LIST_HEIGHT_IN_CHARS * VERTICAL_DIALOG_UNITS_PER_CHAR;

	// The top-level control for the field editor.
	private Composite top;
	// The list of selected tags.
	private List selectedList;
	// The list with available and not selected tags.
	private List availableList;
	// The button for adding the contents of
	// the available list to the selected list.
	private Button select;
	// The button for removing the currently-selected list item.
	private Button deselect;
	// The string used to seperate list items
	// in a single String representation.
	private String seperator = DEFAULT_SEPERATOR;
	protected CLabel label;

	private String[][]availableNamesAndValues;

	public AddRemoveListFieldEditor(
	String name,
	String labelText,
	String[][] availableNamesAndValues,
	Composite parent) {
	super(name, labelText, parent);
	this.availableNamesAndValues = availableNamesAndValues;
	}

	public AddRemoveListFieldEditor(
	String name,
	String labelText,
	String[][] availableNamesAndValues,
	String selectButtonText,
	String deselectButtonText,
	Composite parent) {
	this(name, labelText, availableNamesAndValues, parent);
	setSelectButtonText(selectButtonText);
	setDeselectButtonText(deselectButtonText);
	}

	public void setAvailableNamesAndValues(String[][] availableNamesAndValues) {
	this.availableNamesAndValues = availableNamesAndValues;
	refreshAvailableList();
	}

	/**
	* @see org.eclipse.jface.preference.FieldEditor#adjustForNumColumns(int)
	*/
	protected void adjustForNumColumns(int numColumns) {
	((GridData)top.getLayoutData()).horizontalSpan = numColumns;
	}

	/**
	* @see org.eclipse.jface.preference.FieldEditor#doFillIntoGrid
	* (Composite, int)
	*/
	protected void doFillIntoGrid(Composite parent, int numColumns) {
	top = parent;

	int buttonWidth = convertHorizontalDLUsToPixels(top, IDialogConstants.BUTTON_WIDTH);
	int buttonHeight = convertVerticalDLUsToPixels(top, IDialogConstants.BUTTON_HEIGHT);

	GridData gd = new GridData(GridData.FILL_HORIZONTAL);
	gd.horizontalSpan = numColumns;
	top.setLayoutData(gd);

	getLabelControl(top);
	GridData labelData = new GridData();
	labelData.horizontalSpan = numColumns;
	label.setLayoutData(labelData);

	Composite components = new Composite(top, SWT.NONE);

	GridData componentsData = new GridData();
	componentsData.horizontalSpan = numColumns;
	componentsData.heightHint = buttonHeight * 10+10;
	components.setLayoutData(componentsData);
	//components.setBackground(new org.eclipse.swt.graphics.Color(components.getDisplay(), 255,255,255));
	GridLayout componentsLayout = new GridLayout(3, false);
	components.setLayout(componentsLayout);

	selectedList = new List(components, SWT.BORDER \| SWT.V_SCROLL);
	GridData selectedData = new GridData();
	selectedData.heightHint = buttonHeight * 10;
	selectedList.setLayoutData(selectedData);
	//selectedList.setBackground(new org.eclipse.swt.graphics.Color(components.getDisplay(), 255,0,0));

	// Create a grid data that takes up the extra
	// space in the dialog and spans both columns.
	//*GridData selectedListData = new GridData(GridData.FILL_HORIZONTAL);
	//*selectedListData.heightHint = convertVerticalDLUsToPixels(selectedList, LIST_HEIGHT_IN_DLUS);
	//*selectedListData.horizontalSpan = numColumns;

	//*selectedList.setLayoutData(selectedListData);
	selectedList.addSelectionListener(new SelectionAdapter() {
	public void widgetSelected(SelectionEvent e) {
	selectedSelectionChanged();
	}
	});

	// Create a composite for the add and remove
	// buttons and the input text field.
	Composite addRemoveGroup = new Composite(components, SWT.NONE);
	// GridData addRemoveData = new GridData();
	// addRemoveData.heightHint = buttonHeight * 10;
	// addRemoveGroup.setLayoutData(addRemoveData);
	//addRemoveGroup.setBackground(new org.eclipse.swt.graphics.Color(components.getDisplay(), 0,255,0));

	//*GridData addRemoveData = new GridData(GridData.FILL_HORIZONTAL);
	//*addRemoveData.horizontalSpan = numColumns;
	//*addRemoveGroup.setLayoutData(addRemoveData);

	GridLayout addRemoveLayout = new GridLayout();
	addRemoveLayout.numColumns = numColumns;
	addRemoveLayout.marginHeight = 0;
	addRemoveLayout.marginWidth = 0;
	addRemoveGroup.setLayout(addRemoveLayout);
	addRemoveGroup.setSize(buttonWidth, buttonHeight*2);

	// Create a composite for the add and remove buttons.
	Composite buttonGroup = new Composite(addRemoveGroup, SWT.NONE);
	//*buttonGroup.setLayoutData(new GridData());

	GridLayout buttonLayout = new GridLayout();
	buttonLayout.marginHeight = 0;
	buttonLayout.marginWidth = 0;
	buttonGroup.setLayout(buttonLayout);

	// Create the remove button.
	deselect = new Button(buttonGroup, SWT.NONE);
	deselect.setEnabled(false);
	deselect.setText(DEFAULT_DESELECT_LABEL);
	deselect.addSelectionListener(new SelectionAdapter() {
	public void widgetSelected(SelectionEvent e) {
	deselect();
	showDefaultHint();
	}
	});
	GridData removeData = new GridData(GridData.FILL_HORIZONTAL);
	removeData.heightHint = buttonHeight;
	removeData.widthHint = buttonWidth;
	deselect.setLayoutData(removeData);

	// Create the add button.
	select = new Button(buttonGroup, SWT.NONE);
	select.setEnabled(false);
	select.setText(DEFAULT_SELECT_LABEL);
	select.addSelectionListener(new SelectionAdapter() {
	public void widgetSelected(SelectionEvent e) {
	select();
	showDefaultHint();
	}
	});
	GridData addData = new GridData(GridData.FILL_HORIZONTAL);
	addData.heightHint = buttonHeight;
	addData.widthHint = buttonWidth;
	select.setLayoutData(addData);

	// available list
	availableList = new List(components, SWT.BORDER \| SWT.V_SCROLL);
	GridData availableData = new GridData();
	availableData.heightHint = buttonHeight * 10;
	availableList.setLayoutData(availableData);
	//availableList.setBackground(new org.eclipse.swt.graphics.Color(components.getDisplay(), 0,0,255));

	// Create a grid data that takes up the extra
	// space in the dialog and spans both columns.
	//*GridData availableListData = new GridData(GridData.FILL_HORIZONTAL);
	//*availableListData.heightHint = convertVerticalDLUsToPixels(availableList, LIST_HEIGHT_IN_DLUS);
	//*availableListData.horizontalSpan = numColumns;

	//*availableList.setLayoutData(availableListData);
	availableList.addSelectionListener(new SelectionAdapter() {
	public void widgetSelected(SelectionEvent e) {
	availableSelectionChanged();
	}
	});
	}

	protected void showDefaultHint() {
	String defaults = getPreferenceStore().getDefaultString(getPreferenceName());
	String selected = createListString(selectedList.getItems());
	APreferencePage.showLabelDefaultHint(label, defaults.equals(selected));
	}

	@Override
	public Label getLabelControl(Composite parent) {
	if (label == null) {
	label = new CLabel(parent, SWT.LEFT \| SWT.RIGHT_TO_LEFT);
	label.setFont(parent.getFont());
	String text = getLabelText();
	if (text != null) {
	label.setText(text);
	}
	label.addDisposeListener(new DisposeListener() {
	@Override
	public void widgetDisposed(DisposeEvent event) {
	label = null;
	}
	});
	} else {
	checkParent(label, parent);
	}
	return null;
	}

	@Override
	public void setEnabled(boolean enabled, Composite parent) {
	label.setEnabled(enabled);
	}

	/**
	* @see org.eclipse.jface.preference.FieldEditor#doLoad()
	*/
	protected void doLoad() {
	String items = getPreferenceStore().getString(getPreferenceName());
	setList(items);
	showDefaultHint();
	}

	/**
	* @see org.eclipse.jface.preference.FieldEditor#doLoadDefault()
	*/
	protected void doLoadDefault() {
	String items = getPreferenceStore().getDefaultString(getPreferenceName());
	setList(items);
	showDefaultHint();
	}

	// Parses the string into seperate list items and adds them to the list.
	private void setList(String items) {
	String[] itemArray = parseString(items);
	selectedList.setItems(itemArray);
	}

	/**
	* @see org.eclipse.jface.preference.FieldEditor#doStore()
	*/
	protected void doStore() {
	String s = createListString(selectedList.getItems());
	if (s != null)
	getPreferenceStore().setValue(getPreferenceName(), s);
	}

	/**
	* @see org.eclipse.jface.preference.FieldEditor#getNumberOfControls()
	*/
	public int getNumberOfControls() {
	// The button composite and the text field.
	return 2;
	}

	// Adds the string in the text field to the list.
	private void select() {
	Set<String> items = new TreeSet<String>();
	items.addAll(Arrays.asList(selectedList.getItems()));
	items.addAll(Arrays.asList(availableList.getSelection()));
	selectedList.removeAll();
	for (String addItem : items) {
	selectedList.add(addItem);
	}
	refreshAvailableList();
	}

	private void deselect() {
	Set<String> items = new TreeSet<String>();
	items.addAll(Arrays.asList(selectedList.getItems()));
	items.removeAll(Arrays.asList(selectedList.getSelection()));
	selectedList.removeAll();
	for (String addItem : items) {
	selectedList.add(addItem);
	}
	refreshAvailableList();
	}

	private void refreshAvailableList() {
	java.util.List<String> ignoreItems = Arrays.asList(selectedList.getItems());
	availableList.removeAll();
	for (int idx = 0; idx < availableNamesAndValues.length; idx++) {
	String addItem = availableNamesAndValues[idx][1];
	if ((addItem != null) && !ignoreItems.contains(addItem)) {
	availableList.add(addItem);
	}
	}
	selectedList.deselectAll();
	availableList.deselectAll();
	select.setEnabled(false);
	deselect.setEnabled(false);
	}

	/**
	* Sets the label for the button that adds
	* the contents of the text field to the list.
	*/
	public void setSelectButtonText(String text) {
	select.setText(text);
	}

	/**
	* Sets the label for the button that removes
	* the selected item from the list.
	*/
	public void setDeselectButtonText(String text) {
	deselect.setText(text);
	}

	/**
	* Sets the string that seperates items in the list when the
	* list is stored as a single String in the preference store.
	*/
	public void setSeperator(String seperator) {
	this.seperator = seperator;
	}

	/**
	* Creates the single String representation of the list
	* that is stored in the preference store.
	*/
	private String createListString(String[] items) {
	StringBuffer path = new StringBuffer("");//$NON-NLS-1$
	for (int i = 0; i < items.length; i++) {
	if (i > 0) {
	path.append(seperator);
	}
	path.append(items[i]);
	}
	return path.toString();
	}

	/**
	* Parses the single String representation of the list
	* into an array of list items.
	*/
	private String[] parseString(String stringList) {
	StringTokenizer st =
	new StringTokenizer(stringList, seperator); //$NON-NLS-1$
	ArrayList v = new ArrayList();
	while (st.hasMoreElements()) {
	v.add(st.nextElement());
	}
	return (String[])v.toArray(new String[v.size()]);
	}

	// Sets the enablement of the remove button depending
	// on the selection in the list.
	private void selectedSelectionChanged() {
	int index = selectedList.getSelectionIndex();
	deselect.setEnabled(index >= 0);
	availableList.deselectAll();
	select.setEnabled(false);
	}

	// Sets the enablement of the remove button depending
	// on the selection in the list.
	private void availableSelectionChanged() {
	int index = availableList.getSelectionIndex();
	select.setEnabled(index >= 0);
	selectedList.deselectAll();
	deselect.setEnabled(false);
	}
	}