BUG: 0005493 - This seems to fix the vector writing and read back issues with Paraview saving Xdmf.

ENH:Added a SetTimeValue method, for supporting multiple time steps in the same xdmf file.
Added lag AppendGridsToDomain, to allow multiple grids into one file.
Added a flag InputsArePieces, this allows blocks(pieces)  to be added one by one and then all written as one large dataset.
Added FullGridSize  method to support piece writing.
Various other small bug tweaks addressed with extents and hdf5 read/write issues

vtk/vtkXdmfWriter.h

@@ -28,11 +28,19 @@
 
 #include "vtkProcessObject.h"
 
+// from "XdmfGrid.h"
+#define XDMF_GRID_COLLECTION_TEMPORAL   0x0001
+#define XDMF_GRID_COLLECTION_SPATIAL    0x0002
+#define XDMF_GRID_COLLECTION_UNSET      0x0FFFF
+
 class vtkDataSet;
 class vtkPoints;
 class vtkCellArray;
 class vtkDataArray;
 class vtkDataSetCollection;
+//BTX
+class XdmfDOM;
+//ETX
 
 class VTK_EXPORT vtkXdmfWriter : public vtkProcessObject
 {
@@ -90,6 +98,44 @@ public:
   // Set the input data set.
   virtual void SetInput(vtkDataSet* ds);
 
+  // Description:
+  // If InputsArePieces is set, the onpuits are considered to be parts/pieces
+  // of a larger grid and are joined together inside the hdf5 file
+  vtkSetClampMacro(InputsArePieces, int, 0, 1);
+  vtkBooleanMacro(InputsArePieces, int);
+  vtkGetMacro(InputsArePieces, int);
+
+  // Description:
+  // When InputsArePieces is set, this is the true size of the data
+  vtkSetVector3Macro(FullGridSize, int);
+  vtkGetVectorMacro(FullGridSize, int, 3);
+
+  // Description:
+  // If appending many time steps together into a single file
+  // you should set CollectionType to "Temporal", 
+  // when appending grids into a multi-block type structure
+  // use collection type is "Spatial". By default, Collection type is Unset
+  vtkSetMacro(CollectionType, int);
+  vtkGetMacro(CollectionType, int);
+  void SetCollectionTypeToTemporal() { 
+    this->SetCollectionType(XDMF_GRID_COLLECTION_TEMPORAL); }
+  void SetCollectionTypeToSpatial()  { 
+    this->SetCollectionType(XDMF_GRID_COLLECTION_SPATIAL); }
+  void CloseCollection();
+    
+  // Description:
+  // Set the time value of this data
+  vtkSetMacro(TimeValue, double);
+  vtkGetMacro(TimeValue, double);
+
+  // Description:
+  // If AppendGridsToDomain is set, the existing xdmf xml file is opeded
+  // and new grid are added to the existing domain inside it.
+  // No checking is performed on the structuire of the file.
+  vtkSetClampMacro(AppendGridsToDomain, int, 0, 1);
+  vtkBooleanMacro(AppendGridsToDomain, int);
+  vtkGetMacro(AppendGridsToDomain, int);
+
   // Description:
   // Write the XDMF file.
   void Write();
@@ -146,7 +192,10 @@ protected:
   virtual int WriteVTKArray( ostream& ost, vtkDataArray* array, vtkDataSet* dataSet,
     int dims[3], int *extents, const char* name, const char* dataName, const char* gridName, int alllight,
     int cellData = 0);
-
+  
+  virtual bool ReadDocument(const char* filename);
+  virtual int  ParseExistingFile(const char* filename);
+  
   vtkSetStringMacro(HeavyDataSetNameString);
   char    *HeavyDataSetNameString;
 
@@ -163,6 +212,11 @@ protected:
 
   int GridOnly;
 
+  int AppendGridsToDomain;
+  int InputsArePieces;
+  int FullGridSize[3];
+  double TimeValue;
+
   vtkSetStringMacro(HDF5ArrayName);
   char* HDF5ArrayName;
 
@@ -170,6 +224,13 @@ protected:
   // Here as a convenience.  It is a copy of the input array.
   vtkDataSetCollection *InputList;
 
+  char *DocString;
+  int   CollectionType;
+  XdmfDOM  *DOM;
+
+public:
+  int CurrentInputNumber;
+
 private:
   vtkXdmfWriter(const vtkXdmfWriter&); // Not implemented
   void operator=(const vtkXdmfWriter&); // Not implemented