Bug 138608 [Viewers] JFace AbstractTreeViewer: itemExists doesn't handle equal tree entries
I use a TreeViewer with - setUseHashLookup(true) - without any sorter or filter - with a comparer When I try to add an object that is equal to an existing entry in the tree, it will not be added. This is because the method private boolean itemExists(Item[] items, Object element) { if(usingElementMap()) { return findItem(element) != null; } for (int i = 0; i < items.length; i++) { if(items[i].getData().equals(element)) { return true; } } return false; } takes a shortcut if there is an element map, but the shortcut doesn't handle the 'multiple equal elements' case. There is a workaround, however: Setting a dummy sorter will avoid the call to itemExists and multiple equal elements can be added to the tree.
bundles/org.eclipse.jface/src/org/eclipse/jface/viewers/AbstractTreeViewer.java
}
                }
            }
        }
        
        for (int i = 0; i < min; ++i) {
            Item item = items[i];
            Object newElement = elementChildren[i];
            if (item.getData() == null) {
                
                associate(newElement, item);
                updatePlus(item, newElement);
                updateItem(item, newElement);
            } else {
                
                updatePlus(item, newElement);
                if (updateLabels) {
                    updateItem(item, newElement);
                }
            }
        }
        
        
        
        
        
        
        
        for (int i = 0; i < min; ++i) {
        	Item item = items[i];