org.eclipse.nebula.widgets.nattable.core/src/org/eclipse/nebula/widgets/nattable/filterrow/combobox/FilterNatCombo.java - nattable/org.eclipse.nebula.widgets.nattable - Git at Google

 /*******************************************************************************
  * Copyright (c) 2013, 2020 Dirk Fauth and others.
  *
  * This program and the accompanying materials are made
  * available under the terms of the Eclipse Public License 2.0
  * which is available at https://www.eclipse.org/legal/epl-2.0/
  *
  * SPDX-License-Identifier: EPL-2.0
  *
  * Contributors:
  *    Dirk Fauth <dirk.fauth@googlemail.com> - initial API and implementation
  *    Ryan McHale <rpmc22@gmail.com> - Bug 484716
  *******************************************************************************/
 package org.eclipse.nebula.widgets.nattable.filterrow.combobox;

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

 import org.eclipse.jface.viewers.CheckboxTableViewer;
 import org.eclipse.jface.viewers.ICheckStateListener;
 import org.eclipse.jface.viewers.ICheckStateProvider;
 import org.eclipse.jface.viewers.ILabelProvider;
 import org.eclipse.jface.viewers.ILabelProviderListener;
 import org.eclipse.jface.viewers.IStructuredContentProvider;
 import org.eclipse.jface.viewers.Viewer;
 import org.eclipse.nebula.widgets.nattable.Messages;
 import org.eclipse.nebula.widgets.nattable.style.CellStyleAttributes;
 import org.eclipse.nebula.widgets.nattable.style.HorizontalAlignmentEnum;
 import org.eclipse.nebula.widgets.nattable.style.IStyle;
 import org.eclipse.nebula.widgets.nattable.util.GUIHelper;
 import org.eclipse.nebula.widgets.nattable.widget.NatCombo;
 import org.eclipse.swt.SWT;
 import org.eclipse.swt.events.FocusAdapter;
 import org.eclipse.swt.events.FocusEvent;
 import org.eclipse.swt.events.SelectionAdapter;
 import org.eclipse.swt.events.SelectionEvent;
 import org.eclipse.swt.graphics.Image;
 import org.eclipse.swt.graphics.Point;
 import org.eclipse.swt.layout.FormAttachment;
 import org.eclipse.swt.layout.FormData;
 import org.eclipse.swt.widgets.Composite;
 import org.eclipse.swt.widgets.TableColumn;
 import org.eclipse.swt.widgets.TableItem;
 import org.eclipse.swt.widgets.Text;

 /**
  * Specialisation of NatCombo which doesn't populate the selected values to the
  * Text control. Instead the String representation of the selected values are
  * stored in a local member. Doing this the selection is only visible in the
  * dropdown via selection/check state of the contained items.
  * <p>
  * Usually this combo will be created with the SWT.CHECK style bit. This way the
  * selected items are visualized by showing checked checkboxes. Also adds a
  * <i>Select All</i> item for convenience that de-/selects all items on click.
  */
 public class FilterNatCombo extends NatCombo {

     /**
      * The viewer that contains the select all item in the dropdown control.
      *
      * @since 1.4
      */
     protected CheckboxTableViewer selectAllItemViewer;
     /**
      * The local selection String storage.
      */
     private String filterText;

     /**
      * List of ICheckStateListener that should be added to the select all table
      * once it is created. Kept locally because the table creation is deferred
      * to the first access.
      */
     private List<ICheckStateListener> checkStateListener = new ArrayList<ICheckStateListener>();

     /**
      * Creates a new FilterNatCombo using the given IStyle for rendering,
      * showing the default number of items at once in the dropdown.
      *
      * @param parent
      *            A widget that will be the parent of this NatCombo
      * @param cellStyle
      *            Style configuration containing horizontal alignment, font,
      *            foreground and background color information.
      * @param style
      *            The style for the Text Control to construct. Uses this style
      *            adding internal styles via ConfigRegistry.
      */
     public FilterNatCombo(Composite parent, IStyle cellStyle, int style) {
         this(parent,
                 cellStyle,
                 DEFAULT_NUM_OF_VISIBLE_ITEMS,
                 style,
                 GUIHelper.getImage("down_2")); //$NON-NLS-1$
     }

     /**
      * Creates a new FilterNatCombo using the given IStyle for rendering,
      * showing the given amount of items at once in the dropdown.
      *
      * @param parent
      *            A widget that will be the parent of this NatCombo
      * @param cellStyle
      *            Style configuration containing horizontal alignment, font,
      *            foreground and background color information.
      * @param maxVisibleItems
      *            the max number of items the drop down will show before
      *            introducing a scroll bar.
      * @param style
      *            The style for the Text Control to construct. Uses this style
      *            adding internal styles via ConfigRegistry.
      */
     public FilterNatCombo(Composite parent, IStyle cellStyle, int maxVisibleItems, int style) {
         this(parent,
                 cellStyle,
                 maxVisibleItems,
                 style,
                 GUIHelper.getImage("down_2")); //$NON-NLS-1$
     }

     /**
      * Creates a new FilterNatCombo using the given IStyle for rendering,
      * showing the given amount of items at once in the dropdown.
      *
      * @param parent
      *            A widget that will be the parent of this NatCombo
      * @param cellStyle
      *            Style configuration containing horizontal alignment, font,
      *            foreground and background color information.
      * @param maxVisibleItems
      *            the max number of items the drop down will show before
      *            introducing a scroll bar.
      * @param style
      *            The style for the Text Control to construct. Uses this style
      *            adding internal styles via ConfigRegistry.
      *
      * @param showDropdownFilter
      *            Flag indicating whether the filter of the dropdown control
      *            should be displayed
      *
      * @since 1.4
      */
     public FilterNatCombo(Composite parent, IStyle cellStyle, int maxVisibleItems, int style, boolean showDropdownFilter) {
         this(parent, cellStyle, maxVisibleItems, style, GUIHelper.getImage("down_2"), showDropdownFilter); //$NON-NLS-1$
     }

     /**
      * Creates a new FilterNatCombo using the given IStyle for rendering,
      * showing the given amount of items at once in the dropdown.
      *
      * @param parent
      *            A widget that will be the parent of this NatCombo
      * @param cellStyle
      *            Style configuration containing horizontal alignment, font,
      *            foreground and background color information.
      * @param maxVisibleItems
      *            the max number of items the drop down will show before
      *            introducing a scroll bar.
      * @param style
      *            The style for the {@link Text} Control to construct. Uses this
      *            style adding internal styles via ConfigRegistry.
      * @param iconImage
      *            The image to use as overlay to the {@link Text} Control if the
      *            dropdown is visible. Using this image will indicate that the
      *            control is an open combo to the user.
      */
     public FilterNatCombo(Composite parent, IStyle cellStyle, int maxVisibleItems, int style, Image iconImage) {
         this(parent, cellStyle, maxVisibleItems, style, iconImage, false);
     }

     /**
      * Creates a new FilterNatCombo using the given IStyle for rendering,
      * showing the given amount of items at once in the dropdown.
      *
      * @param parent
      *            A widget that will be the parent of this NatCombo
      * @param cellStyle
      *            Style configuration containing horizontal alignment, font,
      *            foreground and background color information.
      * @param maxVisibleItems
      *            the max number of items the drop down will show before
      *            introducing a scroll bar.
      * @param style
      *            The style for the {@link Text} Control to construct. Uses this
      *            style adding internal styles via ConfigRegistry.
      * @param iconImage
      *            The image to use as overlay to the {@link Text} Control if the
      *            dropdown is visible. Using this image will indicate that the
      *            control is an open combo to the user.
      *
      * @param showDropdownFilter
      *            Flag indicating whether the filter of the dropdown control
      *            should be displayed
      *
      * @since 1.4
      */
     public FilterNatCombo(Composite parent, IStyle cellStyle, int maxVisibleItems, int style, Image iconImage, boolean showDropdownFilter) {
         super(parent, cellStyle, maxVisibleItems, style, iconImage, showDropdownFilter);
     }

     @Override
     protected void calculateBounds() {
         if (this.dropdownShell != null && !this.dropdownShell.isDisposed()) {
             Point size = getSize();

             int gridLineAdjustment = this.dropdownTable.getGridLineWidth() * 2;

             // calculate the height by multiplying the number of visible items
             // with the item height of items in the list and adding 2*grid line
             // width to work around a calculation error regarding the descent of
             // the font metrics for the last shown item
             int listHeight = getVisibleItemCount() * this.dropdownTable.getItemHeight() + gridLineAdjustment;

             // since introduced the TableColumn for real full row selection, we
             // call pack() to perform autoresize to ensure the width shows the
             // whole content
             this.dropdownTable.getColumn(0).pack();
             this.selectAllItemViewer.getTable().getColumn(0).pack();

             int listWidth = Math.max(
                     this.dropdownTable.computeSize(SWT.DEFAULT, listHeight, true).x,
                     size.x);

             int viewerHeight = this.selectAllItemViewer.getTable().getItemHeight();
             listWidth = Math.max(
                     this.selectAllItemViewer.getTable().computeSize(SWT.DEFAULT, viewerHeight, true).x,
                     listWidth);

             Point textPosition = this.text.toDisplay(this.text.getLocation());

             int filterTextBoxHeight = this.showDropdownFilter ? this.filterBox.computeSize(SWT.DEFAULT, SWT.DEFAULT).y : 0;
             this.dropdownShell.setBounds(
                     textPosition.x,
                     textPosition.y + this.text.getBounds().height,
                     listWidth + (this.dropdownTable.getGridLineWidth() * 2),
                     listHeight + viewerHeight + filterTextBoxHeight);

             // as we performed auto resize for the columns, we now need to
             // ensure again that the columns
             // span the whole table width in case they shrunk
             calculateColumnWidth();
         }
     }

     @Override
     protected void calculateColumnWidth() {
         super.calculateColumnWidth();

         this.selectAllItemViewer.getTable().getColumn(0).setWidth(
                 this.dropdownTable.getColumn(0).getWidth());
     }

     @Override
     protected void createDropdownControl(int style) {
         super.createDropdownControl(style);

         int dropdownListStyle = style | SWT.NO_SCROLL
                 | HorizontalAlignmentEnum.getSWTStyle(this.cellStyle)
                 | SWT.FULL_SELECTION;
         this.selectAllItemViewer =
                 CheckboxTableViewer.newCheckList(this.dropdownShell, dropdownListStyle);

         // add a column to be able to resize the item width in the dropdown
         new TableColumn(this.selectAllItemViewer.getTable(), SWT.NONE);
         this.selectAllItemViewer.getTable().addListener(SWT.Resize, event -> calculateColumnWidth());

         FormData data = new FormData();
         if (this.showDropdownFilter) {
             data.top = new FormAttachment(this.filterBox, 0, SWT.BOTTOM);
         } else {
             data.top = new FormAttachment(this.dropdownShell, 0, SWT.TOP);
         }
         data.left = new FormAttachment(0);
         data.right = new FormAttachment(100);
         this.selectAllItemViewer.getTable().setLayoutData(data);

         data = new FormData();
         data.top = new FormAttachment(this.selectAllItemViewer.getControl(), 0, SWT.BOTTOM);
         data.left = new FormAttachment(0);
         data.right = new FormAttachment(100);
         data.bottom = new FormAttachment(100);
         this.dropdownTable.setLayoutData(data);

         this.selectAllItemViewer.setContentProvider(new IStructuredContentProvider() {

             @Override
             public void inputChanged(Viewer viewer, Object oldInput, Object newInput) {
                 // no action on inputChanged
             }

             @Override
             public void dispose() {
                 // no action on dispose
             }

             @SuppressWarnings("unchecked")
             @Override
             public Object[] getElements(Object inputElement) {
                 return ((Collection<String>) inputElement).toArray();
             }
         });

         this.selectAllItemViewer.setLabelProvider(new ILabelProvider() {

             @Override
             public void removeListener(ILabelProviderListener listener) {
                 // no additional listener support
             }

             @Override
             public boolean isLabelProperty(Object element, String property) {
                 return false;
             }

             @Override
             public void dispose() {
                 // no action on dispose
             }

             @Override
             public void addListener(ILabelProviderListener listener) {
                 // no additional listener support
             }

             @Override
             public String getText(Object element) {
                 return element.toString();
             }

             @Override
             public Image getImage(Object element) {
                 return null;
             }
         });

         final String selectAllLabel = Messages.getString("FilterNatCombo.selectAll"); //$NON-NLS-1$
         List<String> input = new ArrayList<String>();
         input.add(selectAllLabel);
         this.selectAllItemViewer.setInput(input);

         this.selectAllItemViewer.getTable().setBackground(
                 this.cellStyle.getAttributeValue(CellStyleAttributes.BACKGROUND_COLOR));
         this.selectAllItemViewer.getTable().setForeground(
                 this.cellStyle.getAttributeValue(CellStyleAttributes.FOREGROUND_COLOR));
         this.selectAllItemViewer.getTable().setFont(
                 this.cellStyle.getAttributeValue(CellStyleAttributes.FONT));

         this.selectAllItemViewer.getTable().addFocusListener(
                 new FocusAdapter() {
                     @Override
                     public void focusGained(FocusEvent e) {
                         showDropdownControl();
                     }
                 });

         this.selectAllItemViewer.addCheckStateListener(event -> {
             if (event.getChecked()) {
                 // select all
                 FilterNatCombo.this.dropdownTable.selectAll();
             } else {
                 // deselect all
                 FilterNatCombo.this.dropdownTable.deselectAll();
             }

             // after selection is performed we need to ensure that
             // selection and checkboxes are in sync
             for (TableItem tableItem : FilterNatCombo.this.dropdownTable.getItems()) {
                 tableItem.setChecked(
                         FilterNatCombo.this.dropdownTable.isSelected(
                                 FilterNatCombo.this.itemList.indexOf(tableItem.getText())));
             }

             // sync the selectionStateMap based on the state of the select
             // all checkbox
             for (String item : FilterNatCombo.this.itemList) {
                 FilterNatCombo.this.selectionStateMap.put(item, event.getChecked());
             }

             updateTextControl(!FilterNatCombo.this.multiselect);
         });

         for (ICheckStateListener l : this.checkStateListener) {
             this.selectAllItemViewer.addCheckStateListener(l);
         }

         // set an ICheckStateProvider that sets the checkbox state of the select
         // all checkbox regarding the selection of the items in the dropdown
         this.selectAllItemViewer.setCheckStateProvider(new ICheckStateProvider() {

             @Override
             public boolean isGrayed(Object element) {
                 return getSelectionCount() < FilterNatCombo.this.itemList.size();
             }

             @Override
             public boolean isChecked(Object element) {
                 return getSelectionCount() > 0;
             }
         });

         // add a selection listener to the items that simply refreshes the
         // select all checkbox
         this.dropdownTable.addSelectionListener(new SelectionAdapter() {
             @Override
             public void widgetSelected(SelectionEvent e) {
                 FilterNatCombo.this.selectAllItemViewer.refresh();
             }
         });
     }

     @Override
     protected void setDropdownSelection(String[] selection) {
         super.setDropdownSelection(selection);
         if (this.selectAllItemViewer != null)
             this.selectAllItemViewer.refresh();
     }

     /**
      * Add an ICheckStateListener to the viewer of the dropdown that contains
      * the select all item. Needed so the editor is able to commit after the
      * click on the select all checkbox is performed.
      *
      * @param listener
      *            The listener to add to the select all item
      */
     public void addCheckStateListener(ICheckStateListener listener) {
         if (listener != null) {
             if (this.selectAllItemViewer != null) {
                 this.selectAllItemViewer.addCheckStateListener(listener);
             }
             this.checkStateListener.add(listener);
         }
     }

     @Override
     protected void updateTextControl(boolean hideDropdown) {
         this.filterText = getTransformedTextForSelection();
         if (hideDropdown) {
             hideDropdownControl();
         }
     }

     @Override
     public int getSelectionIndex() {
         if (!getDropdownTable().isDisposed()) {
             return getDropdownTable().getSelectionIndex();
         } else if (this.filterText != null && this.filterText.length() > 0) {
             return this.itemList.indexOf(this.filterText);
         }
         return -1;
     }

     @Override
     public String[] getSelection() {
         String[] result = getTransformedSelection();
         if (result == null || (result.length == 0 && this.filterText != null)) {
             result = getTextAsArray();
         }
         return result;
     }

     @Override
     public void setSelection(String[] items) {
         String textValue = ""; //$NON-NLS-1$
         if (items != null) {
             if (!getDropdownTable().isDisposed()) {
                 setDropdownSelection(items);
                 if (this.freeEdit
                         && getDropdownTable().getSelectionCount() == 0) {
                     textValue = getTransformedText(items);
                 } else {
                     textValue = getTransformedTextForSelection();
                 }
             } else {
                 textValue = getTransformedText(items);
             }
         }
         this.filterText = textValue;
     }

     @Override
     public void select(int index) {
         if (!getDropdownTable().isDisposed()) {
             getDropdownTable().select(index);
             this.filterText = getTransformedTextForSelection();
         } else if (index >= 0) {
             this.filterText = this.itemList.get(index);
         }
     }

     @Override
     public void select(int[] indeces) {
         if (!getDropdownTable().isDisposed()) {
             getDropdownTable().select(indeces);
             this.filterText = getTransformedTextForSelection();
         } else {
             String[] selectedItems = new String[indeces.length];
             for (int i = 0; i < indeces.length; i++) {
                 if (indeces[i] >= 0) {
                     selectedItems[i] = this.itemList.get(indeces[i]);
                 }
             }
             this.filterText = getTransformedText(selectedItems);
         }
     }

     @Override
     protected String getTransformedText(String[] values) {
         String result = ""; //$NON-NLS-1$
         if (this.multiselect) {
             for (int i = 0; i < values.length; i++) {
                 String selection = values[i];
                 result += selection;
                 if ((i + 1) < values.length) {
                     result += this.multiselectValueSeparator;
                 }
             }
             // if at least one value was selected, add the prefix and suffix
             // we check the values array instead of the result length because
             // there can be also an empty String be selected
             if (values.length > 0) {
                 result = this.multiselectTextPrefix + result + this.multiselectTextSuffix;
             }
         } else if (values.length > 0) {
             result = values[0];
         }
         return result;
     }

     @Override
     protected String[] getTextAsArray() {
         if (this.filterText != null && this.filterText.length() > 0) {
             String transform = this.filterText;
             int prefixLength = this.multiselectTextPrefix.length();
             int suffixLength = this.multiselectTextSuffix.length();
             transform = transform.substring(prefixLength, transform.length() - suffixLength);
             return transform.split(this.multiselectValueSeparator);
         }
         return new String[] {};
     }
 }
	/*******************************************************************************
	* Copyright (c) 2013, 2020 Dirk Fauth and others.
	*
	* This program and the accompanying materials are made
	* available under the terms of the Eclipse Public License 2.0
	* which is available at https://www.eclipse.org/legal/epl-2.0/
	*
	* SPDX-License-Identifier: EPL-2.0
	*
	* Contributors:
	* Dirk Fauth <dirk.fauth@googlemail.com> - initial API and implementation
	* Ryan McHale <rpmc22@gmail.com> - Bug 484716
	*******************************************************************************/
	package org.eclipse.nebula.widgets.nattable.filterrow.combobox;

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

	import org.eclipse.jface.viewers.CheckboxTableViewer;
	import org.eclipse.jface.viewers.ICheckStateListener;
	import org.eclipse.jface.viewers.ICheckStateProvider;
	import org.eclipse.jface.viewers.ILabelProvider;
	import org.eclipse.jface.viewers.ILabelProviderListener;
	import org.eclipse.jface.viewers.IStructuredContentProvider;
	import org.eclipse.jface.viewers.Viewer;
	import org.eclipse.nebula.widgets.nattable.Messages;
	import org.eclipse.nebula.widgets.nattable.style.CellStyleAttributes;
	import org.eclipse.nebula.widgets.nattable.style.HorizontalAlignmentEnum;
	import org.eclipse.nebula.widgets.nattable.style.IStyle;
	import org.eclipse.nebula.widgets.nattable.util.GUIHelper;
	import org.eclipse.nebula.widgets.nattable.widget.NatCombo;
	import org.eclipse.swt.SWT;
	import org.eclipse.swt.events.FocusAdapter;
	import org.eclipse.swt.events.FocusEvent;
	import org.eclipse.swt.events.SelectionAdapter;
	import org.eclipse.swt.events.SelectionEvent;
	import org.eclipse.swt.graphics.Image;
	import org.eclipse.swt.graphics.Point;
	import org.eclipse.swt.layout.FormAttachment;
	import org.eclipse.swt.layout.FormData;
	import org.eclipse.swt.widgets.Composite;
	import org.eclipse.swt.widgets.TableColumn;
	import org.eclipse.swt.widgets.TableItem;
	import org.eclipse.swt.widgets.Text;

	/**
	* Specialisation of NatCombo which doesn't populate the selected values to the
	* Text control. Instead the String representation of the selected values are
	* stored in a local member. Doing this the selection is only visible in the
	* dropdown via selection/check state of the contained items.
	* <p>
	* Usually this combo will be created with the SWT.CHECK style bit. This way the
	* selected items are visualized by showing checked checkboxes. Also adds a
	* <i>Select All</i> item for convenience that de-/selects all items on click.
	*/
	public class FilterNatCombo extends NatCombo {

	/**
	* The viewer that contains the select all item in the dropdown control.
	*
	* @since 1.4
	*/
	protected CheckboxTableViewer selectAllItemViewer;
	/**
	* The local selection String storage.
	*/
	private String filterText;

	/**
	* List of ICheckStateListener that should be added to the select all table
	* once it is created. Kept locally because the table creation is deferred
	* to the first access.
	*/
	private List<ICheckStateListener> checkStateListener = new ArrayList<ICheckStateListener>();

	/**
	* Creates a new FilterNatCombo using the given IStyle for rendering,
	* showing the default number of items at once in the dropdown.
	*
	* @param parent
	* A widget that will be the parent of this NatCombo
	* @param cellStyle
	* Style configuration containing horizontal alignment, font,
	* foreground and background color information.
	* @param style
	* The style for the Text Control to construct. Uses this style
	* adding internal styles via ConfigRegistry.
	*/
	public FilterNatCombo(Composite parent, IStyle cellStyle, int style) {
	this(parent,
	cellStyle,
	DEFAULT_NUM_OF_VISIBLE_ITEMS,
	style,
	GUIHelper.getImage("down_2")); //$NON-NLS-1$
	}

	/**
	* Creates a new FilterNatCombo using the given IStyle for rendering,
	* showing the given amount of items at once in the dropdown.
	*
	* @param parent
	* A widget that will be the parent of this NatCombo
	* @param cellStyle
	* Style configuration containing horizontal alignment, font,
	* foreground and background color information.
	* @param maxVisibleItems
	* the max number of items the drop down will show before
	* introducing a scroll bar.
	* @param style
	* The style for the Text Control to construct. Uses this style
	* adding internal styles via ConfigRegistry.
	*/
	public FilterNatCombo(Composite parent, IStyle cellStyle, int maxVisibleItems, int style) {
	this(parent,
	cellStyle,
	maxVisibleItems,
	style,
	GUIHelper.getImage("down_2")); //$NON-NLS-1$
	}

	/**
	* Creates a new FilterNatCombo using the given IStyle for rendering,
	* showing the given amount of items at once in the dropdown.
	*
	* @param parent
	* A widget that will be the parent of this NatCombo
	* @param cellStyle
	* Style configuration containing horizontal alignment, font,
	* foreground and background color information.
	* @param maxVisibleItems
	* the max number of items the drop down will show before
	* introducing a scroll bar.
	* @param style
	* The style for the Text Control to construct. Uses this style
	* adding internal styles via ConfigRegistry.
	*
	* @param showDropdownFilter
	* Flag indicating whether the filter of the dropdown control
	* should be displayed
	*
	* @since 1.4
	*/
	public FilterNatCombo(Composite parent, IStyle cellStyle, int maxVisibleItems, int style, boolean showDropdownFilter) {
	this(parent, cellStyle, maxVisibleItems, style, GUIHelper.getImage("down_2"), showDropdownFilter); //$NON-NLS-1$
	}

	/**
	* Creates a new FilterNatCombo using the given IStyle for rendering,
	* showing the given amount of items at once in the dropdown.
	*
	* @param parent
	* A widget that will be the parent of this NatCombo
	* @param cellStyle
	* Style configuration containing horizontal alignment, font,
	* foreground and background color information.
	* @param maxVisibleItems
	* the max number of items the drop down will show before
	* introducing a scroll bar.
	* @param style
	* The style for the {@link Text} Control to construct. Uses this
	* style adding internal styles via ConfigRegistry.
	* @param iconImage
	* The image to use as overlay to the {@link Text} Control if the
	* dropdown is visible. Using this image will indicate that the
	* control is an open combo to the user.
	*/
	public FilterNatCombo(Composite parent, IStyle cellStyle, int maxVisibleItems, int style, Image iconImage) {
	this(parent, cellStyle, maxVisibleItems, style, iconImage, false);
	}

	/**
	* Creates a new FilterNatCombo using the given IStyle for rendering,
	* showing the given amount of items at once in the dropdown.
	*
	* @param parent
	* A widget that will be the parent of this NatCombo
	* @param cellStyle
	* Style configuration containing horizontal alignment, font,
	* foreground and background color information.
	* @param maxVisibleItems
	* the max number of items the drop down will show before
	* introducing a scroll bar.
	* @param style
	* The style for the {@link Text} Control to construct. Uses this
	* style adding internal styles via ConfigRegistry.
	* @param iconImage
	* The image to use as overlay to the {@link Text} Control if the
	* dropdown is visible. Using this image will indicate that the
	* control is an open combo to the user.
	*
	* @param showDropdownFilter
	* Flag indicating whether the filter of the dropdown control
	* should be displayed
	*
	* @since 1.4
	*/
	public FilterNatCombo(Composite parent, IStyle cellStyle, int maxVisibleItems, int style, Image iconImage, boolean showDropdownFilter) {
	super(parent, cellStyle, maxVisibleItems, style, iconImage, showDropdownFilter);
	}

	@Override
	protected void calculateBounds() {
	if (this.dropdownShell != null && !this.dropdownShell.isDisposed()) {
	Point size = getSize();

	int gridLineAdjustment = this.dropdownTable.getGridLineWidth() * 2;

	// calculate the height by multiplying the number of visible items
	// with the item height of items in the list and adding 2*grid line
	// width to work around a calculation error regarding the descent of
	// the font metrics for the last shown item
	int listHeight = getVisibleItemCount() * this.dropdownTable.getItemHeight() + gridLineAdjustment;

	// since introduced the TableColumn for real full row selection, we
	// call pack() to perform autoresize to ensure the width shows the
	// whole content
	this.dropdownTable.getColumn(0).pack();
	this.selectAllItemViewer.getTable().getColumn(0).pack();

	int listWidth = Math.max(
	this.dropdownTable.computeSize(SWT.DEFAULT, listHeight, true).x,
	size.x);

	int viewerHeight = this.selectAllItemViewer.getTable().getItemHeight();
	listWidth = Math.max(
	this.selectAllItemViewer.getTable().computeSize(SWT.DEFAULT, viewerHeight, true).x,
	listWidth);

	Point textPosition = this.text.toDisplay(this.text.getLocation());

	int filterTextBoxHeight = this.showDropdownFilter ? this.filterBox.computeSize(SWT.DEFAULT, SWT.DEFAULT).y : 0;
	this.dropdownShell.setBounds(
	textPosition.x,
	textPosition.y + this.text.getBounds().height,
	listWidth + (this.dropdownTable.getGridLineWidth() * 2),
	listHeight + viewerHeight + filterTextBoxHeight);

	// as we performed auto resize for the columns, we now need to
	// ensure again that the columns
	// span the whole table width in case they shrunk
	calculateColumnWidth();
	}
	}

	@Override
	protected void calculateColumnWidth() {
	super.calculateColumnWidth();

	this.selectAllItemViewer.getTable().getColumn(0).setWidth(
	this.dropdownTable.getColumn(0).getWidth());
	}

	@Override
	protected void createDropdownControl(int style) {
	super.createDropdownControl(style);

	int dropdownListStyle = style \| SWT.NO_SCROLL
	\| HorizontalAlignmentEnum.getSWTStyle(this.cellStyle)
	\| SWT.FULL_SELECTION;
	this.selectAllItemViewer =
	CheckboxTableViewer.newCheckList(this.dropdownShell, dropdownListStyle);

	// add a column to be able to resize the item width in the dropdown
	new TableColumn(this.selectAllItemViewer.getTable(), SWT.NONE);
	this.selectAllItemViewer.getTable().addListener(SWT.Resize, event -> calculateColumnWidth());

	FormData data = new FormData();
	if (this.showDropdownFilter) {
	data.top = new FormAttachment(this.filterBox, 0, SWT.BOTTOM);
	} else {
	data.top = new FormAttachment(this.dropdownShell, 0, SWT.TOP);
	}
	data.left = new FormAttachment(0);
	data.right = new FormAttachment(100);
	this.selectAllItemViewer.getTable().setLayoutData(data);

	data = new FormData();
	data.top = new FormAttachment(this.selectAllItemViewer.getControl(), 0, SWT.BOTTOM);
	data.left = new FormAttachment(0);
	data.right = new FormAttachment(100);
	data.bottom = new FormAttachment(100);
	this.dropdownTable.setLayoutData(data);

	this.selectAllItemViewer.setContentProvider(new IStructuredContentProvider() {

	@Override
	public void inputChanged(Viewer viewer, Object oldInput, Object newInput) {
	// no action on inputChanged
	}

	@Override
	public void dispose() {
	// no action on dispose
	}

	@SuppressWarnings("unchecked")
	@Override
	public Object[] getElements(Object inputElement) {
	return ((Collection<String>) inputElement).toArray();
	}
	});

	this.selectAllItemViewer.setLabelProvider(new ILabelProvider() {

	@Override
	public void removeListener(ILabelProviderListener listener) {
	// no additional listener support
	}

	@Override
	public boolean isLabelProperty(Object element, String property) {
	return false;
	}

	@Override
	public void dispose() {
	// no action on dispose
	}

	@Override
	public void addListener(ILabelProviderListener listener) {
	// no additional listener support
	}

	@Override
	public String getText(Object element) {
	return element.toString();
	}

	@Override
	public Image getImage(Object element) {
	return null;
	}
	});

	final String selectAllLabel = Messages.getString("FilterNatCombo.selectAll"); //$NON-NLS-1$
	List<String> input = new ArrayList<String>();
	input.add(selectAllLabel);
	this.selectAllItemViewer.setInput(input);

	this.selectAllItemViewer.getTable().setBackground(
	this.cellStyle.getAttributeValue(CellStyleAttributes.BACKGROUND_COLOR));
	this.selectAllItemViewer.getTable().setForeground(
	this.cellStyle.getAttributeValue(CellStyleAttributes.FOREGROUND_COLOR));
	this.selectAllItemViewer.getTable().setFont(
	this.cellStyle.getAttributeValue(CellStyleAttributes.FONT));

	this.selectAllItemViewer.getTable().addFocusListener(
	new FocusAdapter() {
	@Override
	public void focusGained(FocusEvent e) {
	showDropdownControl();
	}
	});

	this.selectAllItemViewer.addCheckStateListener(event -> {
	if (event.getChecked()) {
	// select all
	FilterNatCombo.this.dropdownTable.selectAll();
	} else {
	// deselect all
	FilterNatCombo.this.dropdownTable.deselectAll();
	}

	// after selection is performed we need to ensure that
	// selection and checkboxes are in sync
	for (TableItem tableItem : FilterNatCombo.this.dropdownTable.getItems()) {
	tableItem.setChecked(
	FilterNatCombo.this.dropdownTable.isSelected(
	FilterNatCombo.this.itemList.indexOf(tableItem.getText())));
	}

	// sync the selectionStateMap based on the state of the select
	// all checkbox
	for (String item : FilterNatCombo.this.itemList) {
	FilterNatCombo.this.selectionStateMap.put(item, event.getChecked());
	}

	updateTextControl(!FilterNatCombo.this.multiselect);
	});

	for (ICheckStateListener l : this.checkStateListener) {
	this.selectAllItemViewer.addCheckStateListener(l);
	}

	// set an ICheckStateProvider that sets the checkbox state of the select
	// all checkbox regarding the selection of the items in the dropdown
	this.selectAllItemViewer.setCheckStateProvider(new ICheckStateProvider() {

	@Override
	public boolean isGrayed(Object element) {
	return getSelectionCount() < FilterNatCombo.this.itemList.size();
	}

	@Override
	public boolean isChecked(Object element) {
	return getSelectionCount() > 0;
	}
	});

	// add a selection listener to the items that simply refreshes the
	// select all checkbox
	this.dropdownTable.addSelectionListener(new SelectionAdapter() {
	@Override
	public void widgetSelected(SelectionEvent e) {
	FilterNatCombo.this.selectAllItemViewer.refresh();
	}
	});
	}

	@Override
	protected void setDropdownSelection(String[] selection) {
	super.setDropdownSelection(selection);
	if (this.selectAllItemViewer != null)
	this.selectAllItemViewer.refresh();
	}

	/**
	* Add an ICheckStateListener to the viewer of the dropdown that contains
	* the select all item. Needed so the editor is able to commit after the
	* click on the select all checkbox is performed.
	*
	* @param listener
	* The listener to add to the select all item
	*/
	public void addCheckStateListener(ICheckStateListener listener) {
	if (listener != null) {
	if (this.selectAllItemViewer != null) {
	this.selectAllItemViewer.addCheckStateListener(listener);
	}
	this.checkStateListener.add(listener);
	}
	}

	@Override
	protected void updateTextControl(boolean hideDropdown) {
	this.filterText = getTransformedTextForSelection();
	if (hideDropdown) {
	hideDropdownControl();
	}
	}

	@Override
	public int getSelectionIndex() {
	if (!getDropdownTable().isDisposed()) {
	return getDropdownTable().getSelectionIndex();
	} else if (this.filterText != null && this.filterText.length() > 0) {
	return this.itemList.indexOf(this.filterText);
	}
	return -1;
	}

	@Override
	public String[] getSelection() {
	String[] result = getTransformedSelection();
	if (result == null \|\| (result.length == 0 && this.filterText != null)) {
	result = getTextAsArray();
	}
	return result;
	}

	@Override
	public void setSelection(String[] items) {
	String textValue = ""; //$NON-NLS-1$
	if (items != null) {
	if (!getDropdownTable().isDisposed()) {
	setDropdownSelection(items);
	if (this.freeEdit
	&& getDropdownTable().getSelectionCount() == 0) {
	textValue = getTransformedText(items);
	} else {
	textValue = getTransformedTextForSelection();
	}
	} else {
	textValue = getTransformedText(items);
	}
	}
	this.filterText = textValue;
	}

	@Override
	public void select(int index) {
	if (!getDropdownTable().isDisposed()) {
	getDropdownTable().select(index);
	this.filterText = getTransformedTextForSelection();
	} else if (index >= 0) {
	this.filterText = this.itemList.get(index);
	}
	}

	@Override
	public void select(int[] indeces) {
	if (!getDropdownTable().isDisposed()) {
	getDropdownTable().select(indeces);
	this.filterText = getTransformedTextForSelection();
	} else {
	String[] selectedItems = new String[indeces.length];
	for (int i = 0; i < indeces.length; i++) {
	if (indeces[i] >= 0) {
	selectedItems[i] = this.itemList.get(indeces[i]);
	}
	}
	this.filterText = getTransformedText(selectedItems);
	}
	}

	@Override
	protected String getTransformedText(String[] values) {
	String result = ""; //$NON-NLS-1$
	if (this.multiselect) {
	for (int i = 0; i < values.length; i++) {
	String selection = values[i];
	result += selection;
	if ((i + 1) < values.length) {
	result += this.multiselectValueSeparator;
	}
	}
	// if at least one value was selected, add the prefix and suffix
	// we check the values array instead of the result length because
	// there can be also an empty String be selected
	if (values.length > 0) {
	result = this.multiselectTextPrefix + result + this.multiselectTextSuffix;
	}
	} else if (values.length > 0) {
	result = values[0];
	}
	return result;
	}

	@Override
	protected String[] getTextAsArray() {
	if (this.filterText != null && this.filterText.length() > 0) {
	String transform = this.filterText;
	int prefixLength = this.multiselectTextPrefix.length();
	int suffixLength = this.multiselectTextSuffix.length();
	transform = transform.substring(prefixLength, transform.length() - suffixLength);
	return transform.split(this.multiselectValueSeparator);
	}
	return new String[] {};
	}
	}