[maybee]

hi I have a question about the following method:

SNIPPET1
template<class Type>
33*Foam::tmp<Foam::fv::gradScheme<Type> > Foam::fv::gradScheme<Type>::New //Return a pointer to a new*gradScheme*created on freestore.
34*(
35* const fvMesh& mesh,
36* Istream& schemeData
37*)
38*{
39* if (fv::debug)
40* {
41* Info<< "gradScheme<Type>::New"
42* "(const fvMesh& mesh, Istream& schemeData) : "
43* "constructing gradScheme<Type>"
44* << endl;
45* }
46*
47* if (schemeData.eof())
48* {
49* FatalIOErrorIn
50* (
51* "gradScheme<Type>::New"
52* "(const fvMesh& mesh, Istream& schemeData)",
53* schemeData
54* ) << "Grad scheme not specified" << endl << endl
55* << "Valid grad schemes are :" << endl
56* << IstreamConstructorTablePtr_->sortedToc()
57* << exit(FatalIOError);
58* }
59*
60* const word schemeName(schemeData);
61*
62* typename IstreamConstructorTable::iterator cstrIter =
63* IstreamConstructorTablePtr_->find(schemeName);
64*
65* if (cstrIter == IstreamConstructorTablePtr_->end())
66* {
67* FatalIOErrorIn
68* (
69* "gradScheme<Type>::New"
70* "(const fvMesh& mesh, Istream& schemeData)",
71* schemeData
72* ) << "Unknown grad scheme " << schemeName << nl << nl
73* << "Valid grad schemes are :" << endl
74* << IstreamConstructorTablePtr_->sortedToc()
75* << exit(FatalIOError);
76* }
77*
78* return cstrIter()(mesh, schemeData); // typename IstreamConstructorTable::iterator cstrIter (siehe oben)
79*}

In line 78 the operator () of class HashTable is called on cstrIter:

//SNIPPET2
template<class T, class Key, class Hash>
  145 inline T& Foam::HashTable<T, Key, Hash>::operator()(const Key& key)
  146 {
  147     iterator iter = this->find(key);
  148 
  149     if (iter == this->end())
  150     {
  151         this->insert(key, T());
  152         return *find(key);
  153     }
  154     else
  155     {
  156         return *iter;
  157     }
  158 }

In SNIPPET1 line 78 what do the second braces "(mesh, schemeData)" mean/do?

greetings
maybee

[ngj]

Hi Maybee,

You will find the "New" functionality in everthing runtime selectionable function. What it basically does is to construct a specific class; in your case a specific gradient scheme. The information in the parenteses is merely the objects needed to construct that specific gradient scheme.

Kind regards,

Niels