# vtkCellLinks.GetCells (vtkIdType ptId) not accessible from Java wrapper
**URL:** https://discourse.vtk.org/t/vtkcelllinks-getcells-vtkidtype-ptid-not-accessible-from-java-wrapper/16442
**Category:** Support
**Created:** [June 3, 2026, 3:16pm UTC](https://discourse.vtk.org/t/vtkcelllinks-getcells-vtkidtype-ptid-not-accessible-from-java-wrapper/16442 "2026-06-03T15:16:37Z")
**Posts on this page:** 6
**Page:** 1
### Author:  [@jMaxR](https://discourse.vtk.org/u/jMaxR)
#### Post date: [June 3, 2026, 3:16pm UTC](https://discourse.vtk.org/t/vtkcelllinks-getcells-vtkidtype-ptid-not-accessible-from-java-wrapper/16442/1 "2026-06-03T15:16:37Z")
I use vtk 9.5 with java wrapper. vtkCellLinks can be instantiated and built (with BuildLinks()), but GetLink() and GetCells() simply do not appear in the Java wrapper. I can’t figure out how vtkCellLinks can be useful if links cannot be retrieved. Maybe (probably) I miss something.
How can I do to retrieve my links ? Do I have to build in Java a ‘parallel’ structure ?
Any hint will be gratefully appreciated.
---
### Author:  [@toddy](https://discourse.vtk.org/u/toddy)
#### Post date: [June 4, 2026, 7:29am UTC](https://discourse.vtk.org/t/vtkcelllinks-getcells-vtkidtype-ptid-not-accessible-from-java-wrapper/16442/2 "2026-06-04T07:29:21Z")
You can forget about `GetLink()`. The return type is not a vtkObject so it won’t be wrapped.
The Java wrapper code does not seem to recognise the return type for GetCells(). I would suggest changing
`vtkIdType* GetCells(vtkIdType ptId)`
to
`long long* GetCells(vtkIdType ptId)`
and then rebuild.
---
### Author:  [@toddy](https://discourse.vtk.org/u/toddy)
#### Post date: [June 5, 2026, 3:15am UTC](https://discourse.vtk.org/t/vtkcelllinks-getcells-vtkidtype-ptid-not-accessible-from-java-wrapper/16442/3 "2026-06-05T03:15:11Z")
Well that doesn’t work, so I tried adding a new method
```auto
void GetLink(vtkIdType ptId, vtkIdType& nCells, vtkIdType*& cells) VTK_SIZEHINT(cells, nCells);
void vtkCellLinks::GetLink(vtkIdType ptId, vtkIdType& nCells, vtkIdType*& cells)
{
Link& link = this->Array[ptId];
nCells = link.ncells;
cells = link.cells;
}
```
but it doesn’t generate Java wrapper code either. However there are other VTK classes which generate correctly e.g. `const vtkIdType* vtkWedge::GetFaceArray()`
This is a mystery to me. @dgobbi Do you know where the translation from **vtkIdType** to **long long** occurs?
---
### Author:  [@toddy](https://discourse.vtk.org/u/toddy)
#### Post date: [June 10, 2026, 3:07am UTC](https://discourse.vtk.org/t/vtkcelllinks-getcells-vtkidtype-ptid-not-accessible-from-java-wrapper/16442/4 "2026-06-10T03:07:49Z")
This works
```auto
#include "vtkIdTypeArray.h"
void GetCells(vtkIdType ptId, vtkIdTypeArray* cells);
void vtkCellLinks::GetCells(vtkIdType ptId, vtkIdTypeArray* cells)
{
vtkIdType count = this->Array[ptId].ncells;
cells->SetNumberOfValues(count);
cells->SetArray(this->Array[ptId].cells, count, 1);
}
```
---
### Author:  [@jMaxR](https://discourse.vtk.org/u/jMaxR)
#### Post date: [June 10, 2026, 1:43pm UTC](https://discourse.vtk.org/t/vtkcelllinks-getcells-vtkidtype-ptid-not-accessible-from-java-wrapper/16442/5 "2026-06-10T13:43:00Z")
Thanks!
I’ll try to figure out how to incorporate this into my codebase.
Thanks again!
---
### Author:  [@toddy](https://discourse.vtk.org/u/toddy)
#### Post date: [June 11, 2026, 12:09am UTC](https://discourse.vtk.org/t/vtkcelllinks-getcells-vtkidtype-ptid-not-accessible-from-java-wrapper/16442/6 "2026-06-11T00:09:14Z")
The problem is that the original `GetCells()` method contains no information indicating the size of the array to return. This could be patched in the wrapper code if VTK\_SIZEHINT was modified to take a function call.
As a work-around you can paste the code shown above into your VTK source file and rebuild. A new method will be generated in the Java wrapper, so that you can do something like
```auto
vtkIdTypeArray cells = new vtkIdTypeArray();
links.GetCells(id, cells);
```