I've got it half working but it has 2 issues,
1st while is does sort when set right (sortable: true but serverSorting: false) it will only sort the present page of results
2nd with serverSorting: true it won't do any sorting but will post the parameters:-
page 1
pageSize 10
skip 0
sort[0][dir] asc
sort[0][field] Ward
take 10
ofc in the controller json it doesn't pickup/understand it in that format
public JsonResult _List(Request request, int skip, int take)
or
public JsonResult _List(List<SortDescription> sort, int skip, int take)
both will have count = 1 when I click to sort a column but both have field/dir null even if I just try string field, string dir.
So far as I can see I'm not correctly sending the sort data from the view to the controller but then I can't seem to find anywhere that it clearly indicates how it gets from point a to point b and is then implemented in the json.
Anybody have any ideas or suggestions?
You can try to use the KendoGridBinderEx project which maps the query parameters to an object (KendoGridRequest).
The controller looks like this:
[HttpPost]
public JsonResult _List(KendoGridRequest request)
{
var entities = _employeeService.AsQueryable();
return GetKendoGridAsJson(request, entities);
}
Related
I am using the postsharp cache and I have created a sample function to cache the result of that - but I want to do caching based on parameter values only.
For example, my function looks like this
[Cache(SlidingExpiration = OneHour, IgnoreThisParameter = true )]
public IEnumerable<String> Get(int dateId)
{
// code processing
}
I want the output of this function to be cached if the dateid= T-1 (yesterday) and not when dateid is not T.
But with [Cache] attribute decorated, everything gets cached. Basically I want to cache T-1 data only and not data for any other dates.
This pattern is used so that we can invalidate the caches using custom methods but I dont see any option for selective parameter value based caching.
Can anybody respond to this?
Currently this is not possible. At this moment you need to split method into three methods and have:
public IEnumerable<string> Get(int dateId)
{
if (dateId == CurrentDate - 1)
GetCached(dateId);
else
GetCore(dateId);
}
[Cache(SlidingExpiration = OneHour, IgnoreThisParameter = true )]
private IEnumerable<string> GetCached(int dateId)
{
return GetCore(dateId);
}
private IEnumerable<string> GetCore(int dateId)
{
// ...
}
This is in the backlog, but it is not scheduled to any release at the moment.
I red a lot about sorting a CellTable. I also went trough the ColumnSorting with AsyncDataProvider. But my CellTable does not sort.
Here is my code:
public class EventTable extends CellTable<Event> {
public EventTable() {
EventsDataProvider dataProvider = new EventsDataProvider(this);
dataProvider.addDataDisplay(this);
SimplePager.Resources pagerResources = GWT.create(SimplePager.Resources.class);
SimplePager pager = new SimplePager(TextLocation.CENTER, pagerResources, false, 5, true);
pager.setDisplay(this);
[...]
TextColumn<Event> nameCol = new TextColumn<Event>() {
#Override
public String getValue(Event event) {
return event.getName();
}
};
nameCol.setSortable(true);
AsyncHandler columnSortHandler = new AsyncHandler(this);
addColumnSortHandler(columnSortHandler);
addColumn(nameCol, "Name");
getColumnSortList().push(endCol);
}
}
public class EventsDataProvider extends AsyncDataProvider<Event> {
private final EventTable eventTable;
public EventsDataProvider(EventTable eventTable) {
this.eventTable = eventTable;
}
#Override
protected void onRangeChanged(HasData<Event> display) {
int start = display.getVisibleRange().getStart();
int length = display.getVisibleRange().getLength();
// check false values
if (start < 0 || length < 0) return;
// check Cache before making a rpc
if (pageCached(start, length)) return;
// get Events async
getEvents(start, length);
}
}
I do now know, if all the methods are need here. If so, I will add them. But in short:
pageCached calls a method in my PageCache Class which holds a map and a list. Before making a rpc call, the cache is checked if the events where already taken and then displayed.
getEvents just makes an rpc call via asynccallback which updates the rowdata via updateRowData() on success.
My Table is displayed fast with currently around 500 entries (could be more, depends on the customer). No missing data and the paging works fine.
I just cannot get the sorting work. As far as I know, AsyncHandler will fire a setVisibleRangeAndClearData() and then an onRangeChanged(). onRangeChanged is never fired. As for the setVisibleRangeAndClearData() I do not know. But the sortindicator (arrow next to the columnname) does change on every click.
I do not want to let the server sort the list. I have my own Comparators. It is enough, if the current visible page of the table is sorted. I do now want to sort the whole list.
Edit:
I changed following code in the EventTable constructor:
public EventTable() {
[...]
addColumnSortHandler(new ColumnSortEvent.AsyncHandler(this) {
public void onColumnSort(ColumnSortEvent event) {
super.onColumnSort(event);
MyTextColumn<Event> myTextColumn;
if (event.getColumn() instanceof MyTextColumn) {
// Compiler Warning here: Safetytype unchecked cast
myTextColumn = (MyTextColumn<Event>) event.getColumn();
MyLogger.log(this.getClass().getName(), "asc " + event.isSortAscending() + " " + myTextColumn.getName(), Level.INFO);
}
List<Event> list = dataProvider.getCurrentEventList();
if (list == null) return;
if (event.isSortAscending()) Collections.sort(list, EventsComparator.getComparator(EventsComparator.NAME_SORT));
else Collections.sort(list, EventsComparator.descending(EventsComparator.getComparator(EventsComparator.NAME_SORT)));
}
});
addColumn(nameCol, "Name");
getColumnSortList().push(endCol);
}
I had to write my own TextColumn to determine the Name of the column. Otherwise how should I know, which column was clicked? The page gets sorted now but I have to click twice on the column. After then, the sorting is done with every click but in the wrong order.
This solution does need polishing and it seems kinda hacky to me. Any better ideas?
The tutorial, that you linked to, states:
This sorting code is here so the example works. In practice, you would
sort on the server.
Async provider is used to display data that is too big to be loaded in a single call. When a user clicks on any column to sort it, there is simply not enough objects on the client side to display "first 20 evens by name" or whatever sorting was applied. You have to go back to your server and request these first 20 events sorted by name in ascending order. And when a user reverses sorting, you have to go to the server again to get first 20 events sorted by name in a descending order, etc.
If you can load all data in a single call, then you can use regular DataProvider, and all sorting can happen on the client side.
EDIT:
The problem in the posted code was in the constructor of EventsDataProvider. Now it calls onRangeChanged, and the app can load a new sorted list of events from the server.
Is it possible to fetch data in user defined ranges [int starting record -int last record]?
In my case user will define in query String in which range he wants to fetch data.
I have tried something like this
Pageable pageable = new PageRequest(0, 10);
Page<Project> list = projectRepository.findAll(spec, pageable);
Where spec is my defined specification but unfortunately this do not help.
May be I am doing something wrong here.
I have seen other spring jpa provided methods but nothing are of much help.
user can enter something like this localhost:8080/Section/employee? range{"columnName":name,"from":6,"to":20}
So this says to fetch employee data and it will fetch the first 15 records (sorted by columnName ) does not matter as of now.
If you can suggest me something better that would be great.if you think I have not provided enough information please let me know, I will provide required information.
Update :I do not want to use native or Create query statements (until I don't have any other option).
May be something like this:
Pageable pageable = new PageRequest(0, 10);
Page<Project> list = projectRepository.findAll(spec, new pageable(int startIndex,int endIndex){
// here my logic.
});
If you have better options, you can suggest me that as well.
Thanks.
Your approach didn't work, because new PageRequest(0, 10); doens't do what you think. As stated in docs, the input arguments are page and size, not limit and offset.
As far as I know (and somebody correct me if I'm wrong), there is no "out of the box" support for what you need in default SrpingData repositories. But you can create custom implementation of Pagable, that will take limit/offset parameters. Here is basic example - Spring data Pageable and LIMIT/OFFSET
We can do this with Pagination and by setting the database table column name, value & row counts as below:
#Transactional(readOnly=true)
public List<String> queryEmployeeDetails(String columnName,String columnData, int startRecord, int endRecord) {
Query query = sessionFactory.getCurrentSession().createQuery(" from Employee emp where emp.col= :"+columnName);
query.setParameter(columnName, columnData);
query.setFirstResult(startRecord);
query.setMaxResults(endRecord);
List<String> list = (List<String>)query.list();
return list;
}
If I am understanding your problem correctly, you want your repository to allow user to
Provide criteria for query (through Specification)
Provide column to sort
Provide the range of result to retrieve.
If my understanding is correctly, then:
In order to achieve 1., you can make use of JpaSpecificationExecutor from Spring Data JPA, which allow you to pass in Specificiation for query.
Both 2 and 3 is achievable in JpaSpecificationExecutor by use of Pagable. Pageable allow you to provide the starting index, number of record, and sorting columns for your query. You will need to implement your range-based Pageable. PageRequest is a good reference on what you can implement (or you can extend it I believe).
So i got this working as one of the answer suggested ,i implemented my own Pageable and overrided getPagesize(),getOffset(),getSort() thats it.(In my case i did not need more)
public Range(int startIndex, int endIndex, String sortBy) {
this.startIndex = startIndex;
this.endIndex = endIndex;
this.sortBy = sortBy;
}
#Override
public int getPageSize() {
if (endIndex == 0)
return 0;
return endIndex - startIndex;
}
#Override
public int getOffset() {
// TODO Auto-generated method stub
return startIndex;
}
#Override
public Sort getSort() {
// TODO Auto-generated method stub
if (sortBy != null && !sortBy.equalsIgnoreCase(""))
return new Sort(Direction.ASC, sortBy);
else
return new Sort(Direction.ASC, "id");
}
where startIndex ,endIndex are starting and last index of record.
to access it :
repository.findAll(spec,new Range(0,20,"id");
There is no offset parameter you can simply pass. However there is a very simple solution for this:
int pageNumber = Math.floor(offset / limit) + ( offset % limit );
PageRequest pReq = PageRequest.of(pageNumber, limit);
The client just have to keep track on the offset instead of page number. By this I mean your controller would receive the offset instead of the page number.
Hope this helps!
Why do we have this behavour?
Controller action:
public ActionResult TestProc(List<int> list)
{
return new ContentResult();
}
Request:
/TestProc
leads to a null list. OK
/TestProc?list=[]
leads to an empty list. OK
/TestProc?list=
leads to a list with one item, 0. Not OK. I assume that the binder sees the query string is present, it has no value hence it pushes the default int value in the list, i.e. it treats list= as the same with list=0. I find this confusing. I would have thought that list= is the same with no list at all in this context and I expected list to be null.
I find this confusing
I agree. You could use a nullable integer in this situation:
public ActionResult TestProc(List<int?> list)
This time the model binder will push one element which is null and you will be able to disambiguate between /TestProc?list= and /TestProc?list=0 if you had to.
I am using JQGrid with the Trirand.Web.Mvc class, and trying to figure out how to do custom paging.
I have seen the paging demos here
The problem with these demos is that they bind directly to a linq context object and lets MVC take care of the paging.
// This method is called when the grid requests data. You can choose any method to call
// by setting the JQGrid.DataUrl property
public JsonResult PerformanceLinq_DataRequested()
{
// Get both the grid Model and the data Model
// The data model in our case is an autogenerated linq2sql database based on Northwind.
var gridModel = new OrdersJqGridModel();
var northWindModel = new NorthwindDataContext();
// return the result of the DataBind method, passing the datasource as a parameter
// jqGrid for ASP.NET MVC automatically takes care of paging, sorting, filtering/searching, etc
return gridModel.OrdersGrid.DataBind(northWindModel.OrdersLarges);
}
The data set I want to bind to is quite complex and I am returning it from a stored procedure, which does the paging for me.
So all I have to give JQGrid is the correct size of rows for a specific page of the entire resultset. I can also return the total row count.
So I have my results in a List myListOfObjects.
I can pass this into the DataBind using myListOfObjects.AsQueryable()
The problem is, JQGrid thinks there is only {page size} rows, so does not display any of the paging options.
Is it possible to pass in the total row count?
Other grids, like Teleriks MVC grid allows you to pass in the Total row count, and it displays the paging correctly
Ok, so I've managed to solve this myself. There may be other ways to do it, if so I'd love to hear them!
The JQGrid.DataBind produces an JsonResult object, whose Data value is set to Trirands own object Trirand.Web.Mvc.JsonResponse
It's an internal class to their Trirand.Web.Mvc, so i had to copy its structure which I could see using Visual Studio debugging.
It has:
page - the current page number
records - the total record count
rows - of type Trirand.Web.Mvc.JsonRow (which I need to replicate too)
total - the total number of pages needed
JsonRow looks like:
cell - a string array of your columns
id - your row ID
So my code looked like this:
var jsonList = new List<JSONRow>();
myData.ForEach(x => jsonList.Add(new JSONRow(x)));
var jsonResult = Json (new
{
page = page,
rows = jsonList.ToArray(),
records = totalRows,
total = Math.Round((double)totalRows / rows, MidpointRounding.AwayFromZero)
}, JsonRequestBehavior.AllowGet);
return jsonResult;
My JsonRow looks like this:
public class JSONRow
{
public string[] cell { get; set; }
public string id { get; set; }
public JSONRow(MyObjectType myObject)
{
id = myObject.id;
cell = new string[3];
cell[0] = myObject.Col1;
cell[1] = myObject.Col2?? "";
cell[2] = myObject.Col3?? "";
}
}