Purpose: Implements a node factory used by the EJBQLParser
class.
Responsibilities:
Create EJBQLParseTree instances for EJBQL SELECT-, UPDATE- and DELETE
statements (see methods newSelectStatement, newUpdateStatement and
newDeleteStatement).
Any new<XXX> method returns an instance of the appropriate Node
subclass.
The relationship to the child nodes passed as arguments are
automatically initialized.
Note, this implementation has a state managing the parse tree context
and a list of parameter names for the current parse tree. This state needs
to be initialized before the same node factory implementation instance may
be used to create a second parse tree (see methods initContext and
initParameters).
The implementation automatically adds the list of parameters to the
created parse tree.
The implementation automatically sets the parse tree context for any
created major node.
