bundles/org.eclipse.rap.rwt/src/org/eclipse/swt/widgets/ExpandBar.java - rap/org.eclipse.rap - Git at Google

 /*******************************************************************************
  * Copyright (c) 2008, 2012 Innoopract Informationssysteme GmbH and others.
  * 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:
  *    Innoopract Informationssysteme GmbH - initial API and implementation
  *    EclipseSource - ongoing development
  ******************************************************************************/
 package org.eclipse.swt.widgets;

 import org.eclipse.rap.rwt.graphics.Graphics;
 import org.eclipse.swt.SWT;
 import org.eclipse.swt.SWTException;
 import org.eclipse.swt.events.*;
 import org.eclipse.swt.graphics.*;
 import org.eclipse.swt.internal.widgets.*;


 /**
  * Instances of this class support the layout of selectable expand bar items.
  * <p>
  * The item children that may be added to instances of this class must be of
  * type <code>ExpandItem</code>.
  * </p>
  * <p>
  * <dl>
  * <dt><b>Styles:</b></dt>
  * <dd>V_SCROLL</dd>
  * <dt><b>Events:</b></dt>
  * <dd>Expand, Collapse</dd>
  * </dl>
  * </p>
  * <p>
  * IMPORTANT: This class is <em>not</em> intended to be subclassed.
  * </p>
  *
  * @see ExpandItem
  * @see ExpandEvent
  * @see ExpandListener
  * @see ExpandAdapter
  * @since 1.2
  */
 public class ExpandBar extends Composite {

   private final class ExpandBarAdapter implements IExpandBarAdapter {

     public Rectangle getBounds( ExpandItem item ) {
       int index = ExpandBar.this.indexOf( item );
       return ExpandBar.this.getItem( index ).getBounds();
     }

     public Rectangle getBottomSpacingBounds() {
       return ExpandBar.this.getBottomSpacingBounds();
     }
   }

   private final class ResizeListener extends ControlAdapter {
     @Override
     public void controlResized( ControlEvent event ) {
       layoutItems( 0, true );
     }
   }

   ExpandItem focusItem;
   int spacing;
   int allItemsHeight;
   int charHeight;
   private transient IExpandBarAdapter expandBarAdapter;
   private final ItemHolder<ExpandItem> itemHolder;
   private final ResizeListener resizeListener;

   /**
    * Constructs a new instance of this class given its parent and a style value
    * describing its behavior and appearance.
    * <p>
    * The style value is either one of the style constants defined in class
    * <code>SWT</code> which is applicable to instances of this class, or must
    * be built by <em>bitwise OR</em>'ing together (that is, using the
    * <code>int</code> "|" operator) two or more of those <code>SWT</code>
    * style constants. The class description lists the style constants that are
    * applicable to the class. Style bits are also inherited from superclasses.
    * </p>
    *
    * @param parent a composite control which will be the parent of the new
    *          instance (cannot be null)
    * @param style the style of control to construct
    * @exception IllegalArgumentException
    *              <ul>
    *              <li>ERROR_NULL_ARGUMENT - if the parent is null</li>
    *              </ul>
    * @exception SWTException
    *              <ul>
    *              <li>ERROR_THREAD_INVALID_ACCESS - if not called from the
    *              thread that created the parent</li>
    *              <li>ERROR_INVALID_SUBCLASS - if this class is not an allowed
    *              subclass</li>
    *              </ul>
    * @see Widget#checkSubclass
    * @see Widget#getStyle
    */
   public ExpandBar( Composite parent, int style ) {
     super( parent, checkStyle( style ) );
     spacing = 4;
     resizeListener = new ResizeListener();
     addControlListener( resizeListener );
     itemHolder = new ItemHolder<ExpandItem>( ExpandItem.class );
   }

   /**
    * Adds the listener to the collection of listeners who will be notified when
    * an item in the receiver is expanded or collapsed by sending it one of the
    * messages defined in the <code>ExpandListener</code> interface.
    *
    * @param listener the listener which should be notified
    * @exception IllegalArgumentException
    *              <ul>
    *              <li>ERROR_NULL_ARGUMENT - if the listener is null</li>
    *              </ul>
    * @exception SWTException
    *              <ul>
    *              <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
    *              <li>ERROR_THREAD_INVALID_ACCESS - if not called from the
    *              thread that created the receiver</li>
    *              </ul>
    * @see ExpandListener
    * @see #removeExpandListener
    */
   public void addExpandListener( ExpandListener listener ) {
     checkWidget();
     if( listener == null ) {
       error( SWT.ERROR_NULL_ARGUMENT );
     }
     TypedListener typedListener = new TypedListener( listener );
     addListener( SWT.Expand, typedListener );
     addListener( SWT.Collapse, typedListener );
   }

   /**
    * Removes the listener from the collection of listeners who will be notified
    * when items in the receiver are expanded or collapsed.
    *
    * @param listener the listener which should no longer be notified
    * @exception IllegalArgumentException
    *              <ul>
    *              <li>ERROR_NULL_ARGUMENT - if the listener is null</li>
    *              </ul>
    * @exception SWTException
    *              <ul>
    *              <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
    *              <li>ERROR_THREAD_INVALID_ACCESS - if not called from the
    *              thread that created the receiver</li>
    *              </ul>
    * @see ExpandListener
    * @see #addExpandListener
    */
   public void removeExpandListener( ExpandListener listener ) {
     checkWidget();
     if( listener == null ) {
       error( SWT.ERROR_NULL_ARGUMENT );
     }
     removeListener( SWT.Expand, listener );
     removeListener( SWT.Collapse, listener );
   }

   @Override
   public Point computeSize( int wHint, int hHint, boolean changed ) {
     checkWidget();
     int height = 0, width = 0;
     int itemCount = getItemCount();
     if( wHint == SWT.DEFAULT || hHint == SWT.DEFAULT ) {
       if( itemCount > 0 ) {
         height += spacing;
         for( int i = 0; i < itemCount; i++ ) {
           ExpandItem item = getItem( i );
           height += item.getHeaderHeight();
           if( item.expanded ) {
             height += item.height;
           }
           height += spacing;
           int barPreferredWidth = item.getPreferredWidth() + 2 * spacing;
           width = Math.max( width, barPreferredWidth );
         }
       }
     }
     if( width == 0 ) {
       width = DEFAULT_WIDTH;
     }
     if( height == 0 ) {
       height = DEFAULT_HEIGHT;
     }
     if( wHint != SWT.DEFAULT ) {
       width = wHint;
     }
     if( hHint != SWT.DEFAULT ) {
       height = hHint;
     }
     int border = getBorderWidth();
     width += border * 2;
     height += border * 2;
     if( ( style & SWT.V_SCROLL ) != 0 ) {
       width += getVerticalBar().getSize().x;
     }
     return new Point( width, height );
   }

   void createItem( ExpandItem item, int style, int index ) {
     itemHolder.insert( item, index );
     if( focusItem == null ) {
       focusItem = item;
     }
     layoutItems( index, true );
   }

   void destroyItem( ExpandItem item ) {
     int index = 0;
     int itemCount = getItemCount();
     for( int i = 0; i < itemCount; i++ ) {
       if( getItem( i ) == item ) {
         index = i;
       }
     }
     if( index != itemCount ) {
       if( item == focusItem ) {
         int focusIndex = index > 0
                                   ? index - 1
                                   : 1;
         if( focusIndex < itemCount ) {
           focusItem = getItem( focusIndex );
         } else {
           focusItem = null;
         }
       }
       itemHolder.remove( item );
       layoutItems( index, true );
     }
   }

   @Override
   Control findBackgroundControl() {
     Control control = super.findBackgroundControl();
     if( !isAppThemed() ) {
       if( control == null ) {
         control = this;
       }
     }
     return control;
   }

   int getBandHeight() {
     return Math.max( ExpandItem.CHEVRON_SIZE, charHeight );
   }

   /**
    * Returns the item at the given, zero-relative index in the receiver. Throws
    * an exception if the index is out of range.
    *
    * @param index the index of the item to return
    * @return the item at the given index
    * @exception IllegalArgumentException
    *              <ul>
    *              <li>ERROR_INVALID_RANGE - if the index is not between 0 and
    *              the number of elements in the list minus 1 (inclusive)</li>
    *              </ul>
    * @exception SWTException
    *              <ul>
    *              <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
    *              <li>ERROR_THREAD_INVALID_ACCESS - if not called from the
    *              thread that created the receiver</li>
    *              </ul>
    */
   public ExpandItem getItem( int index ) {
     checkWidget();
     return itemHolder.getItem( index );
   }

   /**
    * Returns the number of items contained in the receiver.
    *
    * @return the number of items
    * @exception SWTException
    *              <ul>
    *              <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
    *              <li>ERROR_THREAD_INVALID_ACCESS - if not called from the
    *              thread that created the receiver</li>
    *              </ul>
    */
   public int getItemCount() {
     checkWidget();
     return itemHolder.size();
   }

   /**
    * Returns an array of <code>ExpandItem</code>s which are the items in the
    * receiver.
    * <p>
    * Note: This is not the actual structure used by the receiver to maintain its
    * list of items, so modifying the array will not affect the receiver.
    * </p>
    *
    * @return the items in the receiver
    * @exception SWTException
    *              <ul>
    *              <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
    *              <li>ERROR_THREAD_INVALID_ACCESS - if not called from the
    *              thread that created the receiver</li>
    *              </ul>
    */
   public ExpandItem[] getItems() {
     checkWidget();
     return itemHolder.getItems();
   }

   /**
    * Returns the receiver's spacing.
    *
    * @return the spacing
    * @exception SWTException
    *              <ul>
    *              <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
    *              <li>ERROR_THREAD_INVALID_ACCESS - if not called from the
    *              thread that created the receiver</li>
    *              </ul>
    */
   public int getSpacing() {
     checkWidget();
     return spacing;
   }

   /**
    * Searches the receiver's list starting at the first item (index 0) until an
    * item is found that is equal to the argument, and returns the index of that
    * item. If no item is found, returns -1.
    *
    * @param item the search item
    * @return the index of the item
    * @exception IllegalArgumentException
    *              <ul>
    *              <li>ERROR_NULL_ARGUMENT - if the item is null</li>
    *              <li>ERROR_INVALID_ARGUMENT - if the item has been disposed</li>
    *              </ul>
    * @exception SWTException
    *              <ul>
    *              <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
    *              <li>ERROR_THREAD_INVALID_ACCESS - if not called from the
    *              thread that created the receiver</li>
    *              </ul>
    */
   public int indexOf( ExpandItem item ) {
     checkWidget();
     if( item == null ) {
       error( SWT.ERROR_NULL_ARGUMENT );
     }
     if( item.isDisposed() ) {
       error( SWT.ERROR_INVALID_ARGUMENT );
     }
     return itemHolder.indexOf( item );
   }

   void layoutItems( int index, boolean setScrollbar ) {
     int itemCount = getItemCount();
     if( index < itemCount ) {
       int y = spacing;
       for( int i = 0; i < index; i++ ) {
         ExpandItem item = getItem( i );
         if( item.expanded ) {
           y += item.height;
         }
         y += item.getHeaderHeight() + spacing;
       }
       for( int i = index; i < itemCount; i++ ) {
         ExpandItem item = getItem( i );
         item.setBounds( spacing, y, 0, 0, true, false );
         if( item.expanded ) {
           y += item.height;
         }
         y += item.getHeaderHeight() + spacing;
       }
     }
     // Calculate all items size
     if( itemCount > 0 ) {
       ExpandItem lastItem = getItem( itemCount - 1 );
       allItemsHeight = lastItem.y + lastItem.getBounds().height;
     }
     updateScrollBars();
     // Set items width based on scrollbar visibility
     Rectangle bounds = getBounds();
     int border = getBorderWidth();
     int scrollBarWidth = getVScrollBarWidth();
     for( int i = 0; i < itemCount; i++ ) {
       ExpandItem item = getItem( i );
       if( isVScrollBarVisible() ) {
         int width = bounds.width - scrollBarWidth - 2 * border - 2 * spacing;
         item.setBounds( 0, 0, width, item.height, false, true );
       } else {
         int width = bounds.width - 2 * border - 2 * spacing;
         item.setBounds( 0, 0, width, item.height, false, true );
       }
     }
   }

   /**
    * Sets the font that the receiver will use to paint textual information
    * to the font specified by the argument, or to the default font for that
    * kind of control if the argument is null.
    *
    * @param font the new font (or null)
    *
    * @exception IllegalArgumentException <ul>
    *    <li>ERROR_INVALID_ARGUMENT - if the argument has been disposed</li>
    *                </ul>
    * @exception SWTException <ul>
    *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
    *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
    *                </ul>
    */
   @Override
   public void setFont( Font font ) {
     if( font != getFont() ) {
       super.setFont( font );
       charHeight = Graphics.getCharHeight( getFont() ) + 4;
     }
   }

   /**
    * Sets the receiver's spacing. Spacing specifies the number of pixels
    * allocated around each item.
    *
    * @exception SWTException
    *              <ul>
    *              <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
    *              <li>ERROR_THREAD_INVALID_ACCESS - if not called from the
    *              thread that created the receiver</li>
    *              </ul>
    */
   public void setSpacing( int spacing ) {
     checkWidget();
     if( spacing >= 0 ) {
       if( spacing != this.spacing ) {
         this.spacing = spacing;
         layoutItems( 0, true );
       }
     }
   }

   void showItem( ExpandItem item ) {
     Control control = item.control;
     if( control != null && !control.isDisposed() ) {
       control.setVisible( item.expanded );
     }
     int index = indexOf( item );
     layoutItems( index + 1, true );
   }

   @Override
   protected void checkSubclass() {
     if( !isValidSubclass() ) {
       error( SWT.ERROR_INVALID_SUBCLASS );
     }
   }

   static int checkStyle( int style ) {
     int aStyle = style & ~SWT.H_SCROLL;
     return aStyle;
   }

   boolean isAppThemed() {
     return false;
   }

   private void updateScrollBars() {
     ScrollBar vScroll = getVerticalBar();
     if( vScroll != null ) {
       vScroll.setVisible( allItemsHeight > getBounds().height - 2 * getBorderWidth() - spacing );
     }
   }

   private boolean isVScrollBarVisible() {
     ScrollBar vScroll = getVerticalBar();
     return vScroll != null && vScroll.getVisible();
   }

   Rectangle getBottomSpacingBounds() {
     return new Rectangle( spacing, allItemsHeight, 10, spacing );
   }

   @Override
   @SuppressWarnings("unchecked")
   public <T> T getAdapter( Class<T> adapter ) {
     T result;
     if( adapter == IItemHolderAdapter.class ) {
       result = ( T )itemHolder;
     } else if( adapter == IExpandBarAdapter.class ) {
       if( expandBarAdapter == null ) {
         expandBarAdapter = new ExpandBarAdapter();
       }
       result = ( T )expandBarAdapter;
     } else {
       result = super.getAdapter( adapter );
     }
     return result;
   }

   /////////////////////
   // Destroy expand bar

   @Override
   void releaseWidget() {
     if( resizeListener != null ) {
       removeControlListener( resizeListener );
     }
     super.releaseWidget();
   }

   @Override
   void releaseChildren() {
     Item[] expandItems = new ExpandItem[ getItemCount() ];
     System.arraycopy( getItems(), 0, expandItems, 0, getItems().length );
     for( int i = 0; i < expandItems.length; i++ ) {
       if( expandItems[ i ] != null ) {
         expandItems[ i ].dispose();
       }
     }
   }

   ////////////////////////////
   // Helping methods - various

   @Override
   int getVScrollBarWidth() {
     int result = 0;
     if( ( style & SWT.V_SCROLL ) != 0 ) {
       result = getVerticalBar().getSize().x;
     }
     return result;
   }

   ///////////////////
   // Skinning support

   @Override
   void reskinChildren( int flags ) {
     ExpandItem[] items = getItems();
     if( items != null ) {
       for( int i = 0; i < items.length; i++ ) {
         ExpandItem item = items[ i ];
         if( item != null ) {
           item.reskin( flags );
         }
       }
     }
     super.reskinChildren( flags );
   }
 }
	/*******************************************************************************
	* Copyright (c) 2008, 2012 Innoopract Informationssysteme GmbH and others.
	* 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:
	* Innoopract Informationssysteme GmbH - initial API and implementation
	* EclipseSource - ongoing development
	******************************************************************************/
	package org.eclipse.swt.widgets;

	import org.eclipse.rap.rwt.graphics.Graphics;
	import org.eclipse.swt.SWT;
	import org.eclipse.swt.SWTException;
	import org.eclipse.swt.events.*;
	import org.eclipse.swt.graphics.*;
	import org.eclipse.swt.internal.widgets.*;


	/**
	* Instances of this class support the layout of selectable expand bar items.
	* <p>
	* The item children that may be added to instances of this class must be of
	* type <code>ExpandItem</code>.
	* </p>
	* <p>
	* <dl>
	* <dt><b>Styles:</b></dt>
	* <dd>V_SCROLL</dd>
	* <dt><b>Events:</b></dt>
	* <dd>Expand, Collapse</dd>
	* </dl>
	* </p>
	* <p>
	* IMPORTANT: This class is <em>not</em> intended to be subclassed.
	* </p>
	*
	* @see ExpandItem
	* @see ExpandEvent
	* @see ExpandListener
	* @see ExpandAdapter
	* @since 1.2
	*/
	public class ExpandBar extends Composite {

	private final class ExpandBarAdapter implements IExpandBarAdapter {

	public Rectangle getBounds( ExpandItem item ) {
	int index = ExpandBar.this.indexOf( item );
	return ExpandBar.this.getItem( index ).getBounds();
	}

	public Rectangle getBottomSpacingBounds() {
	return ExpandBar.this.getBottomSpacingBounds();
	}
	}

	private final class ResizeListener extends ControlAdapter {
	@Override
	public void controlResized( ControlEvent event ) {
	layoutItems( 0, true );
	}
	}

	ExpandItem focusItem;
	int spacing;
	int allItemsHeight;
	int charHeight;
	private transient IExpandBarAdapter expandBarAdapter;
	private final ItemHolder<ExpandItem> itemHolder;
	private final ResizeListener resizeListener;

	/**
	* Constructs a new instance of this class given its parent and a style value
	* describing its behavior and appearance.
	* <p>
	* The style value is either one of the style constants defined in class
	* <code>SWT</code> which is applicable to instances of this class, or must
	* be built by <em>bitwise OR</em>'ing together (that is, using the
	* <code>int</code> "\|" operator) two or more of those <code>SWT</code>
	* style constants. The class description lists the style constants that are
	* applicable to the class. Style bits are also inherited from superclasses.
	* </p>
	*
	* @param parent a composite control which will be the parent of the new
	* instance (cannot be null)
	* @param style the style of control to construct
	* @exception IllegalArgumentException
	* <ul>
	* <li>ERROR_NULL_ARGUMENT - if the parent is null</li>
	* </ul>
	* @exception SWTException
	* <ul>
	* <li>ERROR_THREAD_INVALID_ACCESS - if not called from the
	* thread that created the parent</li>
	* <li>ERROR_INVALID_SUBCLASS - if this class is not an allowed
	* subclass</li>
	* </ul>
	* @see Widget#checkSubclass
	* @see Widget#getStyle
	*/
	public ExpandBar( Composite parent, int style ) {
	super( parent, checkStyle( style ) );
	spacing = 4;
	resizeListener = new ResizeListener();
	addControlListener( resizeListener );
	itemHolder = new ItemHolder<ExpandItem>( ExpandItem.class );
	}

	/**
	* Adds the listener to the collection of listeners who will be notified when
	* an item in the receiver is expanded or collapsed by sending it one of the
	* messages defined in the <code>ExpandListener</code> interface.
	*
	* @param listener the listener which should be notified
	* @exception IllegalArgumentException
	* <ul>
	* <li>ERROR_NULL_ARGUMENT - if the listener is null</li>
	* </ul>
	* @exception SWTException
	* <ul>
	* <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
	* <li>ERROR_THREAD_INVALID_ACCESS - if not called from the
	* thread that created the receiver</li>
	* </ul>
	* @see ExpandListener
	* @see #removeExpandListener
	*/
	public void addExpandListener( ExpandListener listener ) {
	checkWidget();
	if( listener == null ) {
	error( SWT.ERROR_NULL_ARGUMENT );
	}
	TypedListener typedListener = new TypedListener( listener );
	addListener( SWT.Expand, typedListener );
	addListener( SWT.Collapse, typedListener );
	}

	/**
	* Removes the listener from the collection of listeners who will be notified
	* when items in the receiver are expanded or collapsed.
	*
	* @param listener the listener which should no longer be notified
	* @exception IllegalArgumentException
	* <ul>
	* <li>ERROR_NULL_ARGUMENT - if the listener is null</li>
	* </ul>
	* @exception SWTException
	* <ul>
	* <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
	* <li>ERROR_THREAD_INVALID_ACCESS - if not called from the
	* thread that created the receiver</li>
	* </ul>
	* @see ExpandListener
	* @see #addExpandListener
	*/
	public void removeExpandListener( ExpandListener listener ) {
	checkWidget();
	if( listener == null ) {
	error( SWT.ERROR_NULL_ARGUMENT );
	}
	removeListener( SWT.Expand, listener );
	removeListener( SWT.Collapse, listener );
	}

	@Override
	public Point computeSize( int wHint, int hHint, boolean changed ) {
	checkWidget();
	int height = 0, width = 0;
	int itemCount = getItemCount();
	if( wHint == SWT.DEFAULT \|\| hHint == SWT.DEFAULT ) {
	if( itemCount > 0 ) {
	height += spacing;
	for( int i = 0; i < itemCount; i++ ) {
	ExpandItem item = getItem( i );
	height += item.getHeaderHeight();
	if( item.expanded ) {
	height += item.height;
	}
	height += spacing;
	int barPreferredWidth = item.getPreferredWidth() + 2 * spacing;
	width = Math.max( width, barPreferredWidth );
	}
	}
	}
	if( width == 0 ) {
	width = DEFAULT_WIDTH;
	}
	if( height == 0 ) {
	height = DEFAULT_HEIGHT;
	}
	if( wHint != SWT.DEFAULT ) {
	width = wHint;
	}
	if( hHint != SWT.DEFAULT ) {
	height = hHint;
	}
	int border = getBorderWidth();
	width += border * 2;
	height += border * 2;
	if( ( style & SWT.V_SCROLL ) != 0 ) {
	width += getVerticalBar().getSize().x;
	}
	return new Point( width, height );
	}

	void createItem( ExpandItem item, int style, int index ) {
	itemHolder.insert( item, index );
	if( focusItem == null ) {
	focusItem = item;
	}
	layoutItems( index, true );
	}

	void destroyItem( ExpandItem item ) {
	int index = 0;
	int itemCount = getItemCount();
	for( int i = 0; i < itemCount; i++ ) {
	if( getItem( i ) == item ) {
	index = i;
	}
	}
	if( index != itemCount ) {
	if( item == focusItem ) {
	int focusIndex = index > 0
	? index - 1
	: 1;
	if( focusIndex < itemCount ) {
	focusItem = getItem( focusIndex );
	} else {
	focusItem = null;
	}
	}
	itemHolder.remove( item );
	layoutItems( index, true );
	}
	}

	@Override
	Control findBackgroundControl() {
	Control control = super.findBackgroundControl();
	if( !isAppThemed() ) {
	if( control == null ) {
	control = this;
	}
	}
	return control;
	}

	int getBandHeight() {
	return Math.max( ExpandItem.CHEVRON_SIZE, charHeight );
	}

	/**
	* Returns the item at the given, zero-relative index in the receiver. Throws
	* an exception if the index is out of range.
	*
	* @param index the index of the item to return
	* @return the item at the given index
	* @exception IllegalArgumentException
	* <ul>
	* <li>ERROR_INVALID_RANGE - if the index is not between 0 and
	* the number of elements in the list minus 1 (inclusive)</li>
	* </ul>
	* @exception SWTException
	* <ul>
	* <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
	* <li>ERROR_THREAD_INVALID_ACCESS - if not called from the
	* thread that created the receiver</li>
	* </ul>
	*/
	public ExpandItem getItem( int index ) {
	checkWidget();
	return itemHolder.getItem( index );
	}

	/**
	* Returns the number of items contained in the receiver.
	*
	* @return the number of items
	* @exception SWTException
	* <ul>
	* <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
	* <li>ERROR_THREAD_INVALID_ACCESS - if not called from the
	* thread that created the receiver</li>
	* </ul>
	*/
	public int getItemCount() {
	checkWidget();
	return itemHolder.size();
	}

	/**
	* Returns an array of <code>ExpandItem</code>s which are the items in the
	* receiver.
	* <p>
	* Note: This is not the actual structure used by the receiver to maintain its
	* list of items, so modifying the array will not affect the receiver.
	* </p>
	*
	* @return the items in the receiver
	* @exception SWTException
	* <ul>
	* <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
	* <li>ERROR_THREAD_INVALID_ACCESS - if not called from the
	* thread that created the receiver</li>
	* </ul>
	*/
	public ExpandItem[] getItems() {
	checkWidget();
	return itemHolder.getItems();
	}

	/**
	* Returns the receiver's spacing.
	*
	* @return the spacing
	* @exception SWTException
	* <ul>
	* <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
	* <li>ERROR_THREAD_INVALID_ACCESS - if not called from the
	* thread that created the receiver</li>
	* </ul>
	*/
	public int getSpacing() {
	checkWidget();
	return spacing;
	}

	/**
	* Searches the receiver's list starting at the first item (index 0) until an
	* item is found that is equal to the argument, and returns the index of that
	* item. If no item is found, returns -1.
	*
	* @param item the search item
	* @return the index of the item
	* @exception IllegalArgumentException
	* <ul>
	* <li>ERROR_NULL_ARGUMENT - if the item is null</li>
	* <li>ERROR_INVALID_ARGUMENT - if the item has been disposed</li>
	* </ul>
	* @exception SWTException
	* <ul>
	* <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
	* <li>ERROR_THREAD_INVALID_ACCESS - if not called from the
	* thread that created the receiver</li>
	* </ul>
	*/
	public int indexOf( ExpandItem item ) {
	checkWidget();
	if( item == null ) {
	error( SWT.ERROR_NULL_ARGUMENT );
	}
	if( item.isDisposed() ) {
	error( SWT.ERROR_INVALID_ARGUMENT );
	}
	return itemHolder.indexOf( item );
	}

	void layoutItems( int index, boolean setScrollbar ) {
	int itemCount = getItemCount();
	if( index < itemCount ) {
	int y = spacing;
	for( int i = 0; i < index; i++ ) {
	ExpandItem item = getItem( i );
	if( item.expanded ) {
	y += item.height;
	}
	y += item.getHeaderHeight() + spacing;
	}
	for( int i = index; i < itemCount; i++ ) {
	ExpandItem item = getItem( i );
	item.setBounds( spacing, y, 0, 0, true, false );
	if( item.expanded ) {
	y += item.height;
	}
	y += item.getHeaderHeight() + spacing;
	}
	}
	// Calculate all items size
	if( itemCount > 0 ) {
	ExpandItem lastItem = getItem( itemCount - 1 );
	allItemsHeight = lastItem.y + lastItem.getBounds().height;
	}
	updateScrollBars();
	// Set items width based on scrollbar visibility
	Rectangle bounds = getBounds();
	int border = getBorderWidth();
	int scrollBarWidth = getVScrollBarWidth();
	for( int i = 0; i < itemCount; i++ ) {
	ExpandItem item = getItem( i );
	if( isVScrollBarVisible() ) {
	int width = bounds.width - scrollBarWidth - 2 * border - 2 * spacing;
	item.setBounds( 0, 0, width, item.height, false, true );
	} else {
	int width = bounds.width - 2 * border - 2 * spacing;
	item.setBounds( 0, 0, width, item.height, false, true );
	}
	}
	}

	/**
	* Sets the font that the receiver will use to paint textual information
	* to the font specified by the argument, or to the default font for that
	* kind of control if the argument is null.
	*
	* @param font the new font (or null)
	*
	* @exception IllegalArgumentException <ul>
	* <li>ERROR_INVALID_ARGUMENT - if the argument has been disposed</li>
	* </ul>
	* @exception SWTException <ul>
	* <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
	* <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
	* </ul>
	*/
	@Override
	public void setFont( Font font ) {
	if( font != getFont() ) {
	super.setFont( font );
	charHeight = Graphics.getCharHeight( getFont() ) + 4;
	}
	}

	/**
	* Sets the receiver's spacing. Spacing specifies the number of pixels
	* allocated around each item.
	*
	* @exception SWTException
	* <ul>
	* <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
	* <li>ERROR_THREAD_INVALID_ACCESS - if not called from the
	* thread that created the receiver</li>
	* </ul>
	*/
	public void setSpacing( int spacing ) {
	checkWidget();
	if( spacing >= 0 ) {
	if( spacing != this.spacing ) {
	this.spacing = spacing;
	layoutItems( 0, true );
	}
	}
	}

	void showItem( ExpandItem item ) {
	Control control = item.control;
	if( control != null && !control.isDisposed() ) {
	control.setVisible( item.expanded );
	}
	int index = indexOf( item );
	layoutItems( index + 1, true );
	}

	@Override
	protected void checkSubclass() {
	if( !isValidSubclass() ) {
	error( SWT.ERROR_INVALID_SUBCLASS );
	}
	}

	static int checkStyle( int style ) {
	int aStyle = style & ~SWT.H_SCROLL;
	return aStyle;
	}

	boolean isAppThemed() {
	return false;
	}

	private void updateScrollBars() {
	ScrollBar vScroll = getVerticalBar();
	if( vScroll != null ) {
	vScroll.setVisible( allItemsHeight > getBounds().height - 2 * getBorderWidth() - spacing );
	}
	}

	private boolean isVScrollBarVisible() {
	ScrollBar vScroll = getVerticalBar();
	return vScroll != null && vScroll.getVisible();
	}

	Rectangle getBottomSpacingBounds() {
	return new Rectangle( spacing, allItemsHeight, 10, spacing );
	}

	@Override
	@SuppressWarnings("unchecked")
	public <T> T getAdapter( Class<T> adapter ) {
	T result;
	if( adapter == IItemHolderAdapter.class ) {
	result = ( T )itemHolder;
	} else if( adapter == IExpandBarAdapter.class ) {
	if( expandBarAdapter == null ) {
	expandBarAdapter = new ExpandBarAdapter();
	}
	result = ( T )expandBarAdapter;
	} else {
	result = super.getAdapter( adapter );
	}
	return result;
	}

	/////////////////////
	// Destroy expand bar

	@Override
	void releaseWidget() {
	if( resizeListener != null ) {
	removeControlListener( resizeListener );
	}
	super.releaseWidget();
	}

	@Override
	void releaseChildren() {
	Item[] expandItems = new ExpandItem[ getItemCount() ];
	System.arraycopy( getItems(), 0, expandItems, 0, getItems().length );
	for( int i = 0; i < expandItems.length; i++ ) {
	if( expandItems[ i ] != null ) {
	expandItems[ i ].dispose();
	}
	}
	}

	////////////////////////////
	// Helping methods - various

	@Override
	int getVScrollBarWidth() {
	int result = 0;
	if( ( style & SWT.V_SCROLL ) != 0 ) {
	result = getVerticalBar().getSize().x;
	}
	return result;
	}

	///////////////////
	// Skinning support

	@Override
	void reskinChildren( int flags ) {
	ExpandItem[] items = getItems();
	if( items != null ) {
	for( int i = 0; i < items.length; i++ ) {
	ExpandItem item = items[ i ];
	if( item != null ) {
	item.reskin( flags );
	}
	}
	}
	super.reskinChildren( flags );
	}
	}