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/******************************************************************************* |
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* Copyright (c) 2011 IBM Corporation. |
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* All rights reserved. This program and the accompanying materials |
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* are made available under the terms of the Eclipse Public License v1.0 |
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* which accompanies this distribution, and is available at |
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* http://www.eclipse.org/legal/epl-v10.html |
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* |
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* Contributors: |
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* IBM Corporation - initial implementation |
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*******************************************************************************/ |
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package org.eclipse.mat.ui.accessibility; |
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import org.eclipse.mat.ui.MemoryAnalyserPlugin; |
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import org.eclipse.swt.accessibility.ACC; |
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import org.eclipse.swt.accessibility.AccessibleAdapter; |
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import org.eclipse.swt.accessibility.AccessibleControlAdapter; |
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import org.eclipse.swt.accessibility.AccessibleControlEvent; |
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import org.eclipse.swt.accessibility.AccessibleEvent; |
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import org.eclipse.swt.graphics.Image; |
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import org.eclipse.swt.widgets.Composite; |
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import org.eclipse.swt.widgets.Item; |
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import org.eclipse.swt.widgets.Table; |
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import org.eclipse.swt.widgets.TableItem; |
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import org.eclipse.swt.widgets.Tree; |
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import org.eclipse.swt.widgets.TreeItem; |
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|
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/** |
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* AccessibleCompositeAdapter Accessibility utility class provides a single |
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* encapsulated implementation of accessibility enhancements for Table & Tree |
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* Controls within MAT. The implementation is essentially the same for both |
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* types of view, adding an Accessible Listener to cause a specially constructed |
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* name for each item to be passed to the accessibility client (Screen Reader). |
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* |
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* @author Jonathan Lawrence |
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*/ |
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public class AccessibleCompositeAdapter |
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{ |
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|
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// Constants for String construction. |
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private static final char space = ' '; |
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|
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// Public methods provide interface ensuring only Table or Tree are used. |
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/** |
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* @param table |
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* The Table to decorate with Accessible. |
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*/ |
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public static void access(Table table) |
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{ |
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access(table, ACC.ROLE_TABLE); // Delegate to generic private method. |
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} |
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|
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/** |
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* @param tree |
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* The Tree to decorate with Accessible. |
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*/ |
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public static void access(Tree tree) |
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{ |
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access(tree, ACC.ROLE_TREE); // Delegate to generic private method. |
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} |
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|
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/** |
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* @param composite |
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* The Composite (Table/Tree) to add Accessibility |
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* @param role |
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* The ACC.ROLE constant representing the type of Composite. |
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*/ |
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private static void access(final Composite composite, final int role) |
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{ |
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// Add addAccessibleListener to override getName. |
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composite.getAccessible().addAccessibleListener(new AccessibleAdapter() |
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{ |
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|
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@Override |
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public void getName(AccessibleEvent e) |
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{ |
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if (e.childID == ACC.CHILDID_SELF) |
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{ |
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// TODO - provide a suitable name for the Tree/Table. |
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} |
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else |
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{ // Name is required for a child of the Composite. |
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|
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// Get the item... |
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Item item = null; |
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try |
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{ |
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// Defensive coding. For Tree Controls, JAWS 12 |
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// sometimes |
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// calls this method with invalid childIDs. |
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int maxchild = getItemCount(composite, role); |
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if (e.childID >= 0 && e.childID < maxchild) |
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{ // Valid range |
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// Get Item |
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item = getItem(composite, role, e.childID); |
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} |
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// Otherwise use first selected item if any. |
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else |
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{ |
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item = getSelection(composite, role)[0]; |
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} |
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} |
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catch (IndexOutOfBoundsException ie) |
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{ // Do nothing |
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// item will be null, no name will be returned in e. |
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|
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} // catch() |
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|
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// Construct a row of readable text for the Table/TreeItem |
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if (item != null) // Valid item |
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{ |
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int ncol = getColumnCount(composite, role); |
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int[] colorder = getColumnOrder(composite, role); |
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StringBuffer rowbuf = new StringBuffer(); |
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Item column = null; |
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Image image = null; |
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for (int icol = 0; icol < ncol; icol++) // For each |
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// column |
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{ |
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int jcol = colorder[icol]; // The index of the |
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// column when created. |
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image = getImage(item, role, jcol); // Get image if |
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// any |
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if (image != null) // Image exists in this column |
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{ // Append the descriptive text for this image |
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rowbuf.append(MemoryAnalyserPlugin.getDefault().getImageText(image)); |
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rowbuf.append(space); |
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} |
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column = getColumn(composite, role, jcol); // Get |
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// relevant |
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// Column |
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rowbuf.append(column.getText()); // Append column |
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// header |
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rowbuf.append(space); |
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rowbuf.append(getText(item, role, jcol)); // Append |
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// column |
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// content |
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rowbuf.append(space); |
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} |
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e.result = rowbuf.toString(); |
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} // if() |
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} // if() |
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} // getName() |
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|
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}); |
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|
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// Experimentation with JAWS 12 shows that the following is also |
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// required to ensure |
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// that JAWS will read out the name returned for the Item. |
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composite.getAccessible().addAccessibleControlListener(new AccessibleControlAdapter() |
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{ |
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@Override |
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public void getRole(AccessibleControlEvent e) |
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{ |
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if (e.childID == ACC.CHILDID_SELF) |
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{ |
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e.detail = role; // The ACC.ROLE constant for the Control. |
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} |
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else |
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{ |
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e.detail = ACC.ROLE_TEXT; // Return TEXT for an Item. |
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} // if() |
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} // getRole() |
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}); |
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|
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} |
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|
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// ////////////////////////////////////////////////////////////// |
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// Utility methods to map inquiry methods onto the Control-type |
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// specific variants for Table or Tree, as required. |
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// ////////////////////////////////////////////////////////////// |
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|
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private static Item getColumn(Composite composite, int role, int index) |
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{ |
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return (role == ACC.ROLE_TABLE) ? ((Table) composite).getColumn(index) : ((Tree) composite).getColumn(index); |
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} |
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private static int getColumnCount(Composite composite, int role) |
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{ |
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return (role == ACC.ROLE_TABLE) ? ((Table) composite).getColumnCount() : ((Tree) composite).getColumnCount(); |
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} |
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|
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private static int[] getColumnOrder(Composite composite, int role) |
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{ |
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return (role == ACC.ROLE_TABLE) ? ((Table) composite).getColumnOrder() : ((Tree) composite).getColumnOrder(); |
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} |
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private static Item getItem(Composite composite, int role, int index) |
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{ |
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return (role == ACC.ROLE_TABLE) ? ((Table) composite).getItem(index) : ((Tree) composite).getItem(index); |
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} |
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private static Item[] getSelection(Composite composite, int role) |
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{ |
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return (role == ACC.ROLE_TABLE) ? ((Table) composite).getSelection() : ((Tree) composite).getSelection(); |
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} |
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private static int getItemCount(Composite composite, int role) |
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{ |
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return (role == ACC.ROLE_TABLE) ? ((Table) composite).getItemCount() : ((Tree) composite).getItemCount(); |
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} |
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private static Image getImage(Item item, int role, int index) |
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{ |
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return (role == ACC.ROLE_TABLE) ? ((TableItem) item).getImage(index) : ((TreeItem) item).getImage(index); |
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} |
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private static String getText(Item item, int role, int index) |
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{ |
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return (role == ACC.ROLE_TABLE) ? ((TableItem) item).getText(index) : ((TreeItem) item).getText(index); |
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} |
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} |
