Page expired issue with back button and wicket SortableDataProvider and DataTable
- by David
Hi, I've got an issue with SortableDataProvider and DataTable in wicket.
I've defined my DataTable as such:
IColumn<Column>[] columns = new IColumn[9];
//column values are mapped to the private attributes listed in ColumnImpl.java
columns[0] = new PropertyColumn(new Model("#"), "columnPosition", "columnPosition");
columns[1] = new PropertyColumn(new Model("Description"), "description");
columns[2] = new PropertyColumn(new Model("Type"), "dataType", "dataType");
Adding it to the table:
DataTable<Column> dataTable = new DataTable<Column>("columnsTable", columns, provider, maxRowsPerPage) {
@Override
protected Item<Column> newRowItem(String id, int index, IModel<Column> model) {
return new OddEvenItem<Column>(id, index, model);
}
};
My data provider:
public class ColumnSortableDataProvider extends SortableDataProvider<Column> {
private static final long serialVersionUID = 1L;
private List list = null;
public ColumnSortableDataProvider(Table table, String sortProperty) {
this.list = Arrays.asList(table.getColumns().toArray(new Column[0]));
setSort(sortProperty, true);
}
public ColumnSortableDataProvider(List list, String sortProperty) {
this.list = list;
setSort(sortProperty, true);
}
@Override
public Iterator iterator(int first, int count) {
/*
first - first row of data
count - minimum number of elements to retrieve
So this method returns an iterator capable of iterating over {first, first+count} items
*/
Iterator iterator = null;
try {
if(getSort() != null) {
Collections.sort(list, new Comparator() {
private static final long serialVersionUID = 1L;
@Override
public int compare(Column c1, Column c2) {
int result=1;
PropertyModel<Comparable> model1= new PropertyModel<Comparable>(c1, getSort().getProperty());
PropertyModel<Comparable> model2= new PropertyModel<Comparable>(c2, getSort().getProperty());
if(model1.getObject() == null && model2.getObject() == null)
result = 0;
else if(model1.getObject() == null)
result = 1;
else if(model2.getObject() == null)
result = -1;
else
result = ((Comparable)model1.getObject()).compareTo(model2.getObject());
result = getSort().isAscending() ? result : -result;
return result;
}
});
}
if (list.size() (first+count))
iterator = list.subList(first, first+count).iterator();
else
iterator = list.iterator();
}
catch (Exception e) {
e.printStackTrace();
}
return iterator;
}
The problem is the following:
- I click a column header to sort by that column.
- I navigate to a different page
- I click Back (or Forward if I do the opposite scenario)
- Page has expired.
It'd be nice to generate the page using PageParameters but I somehow need to intercept the sort event to do so.
Any pointers would be greatly appreciated. Thanks a ton!!
David
