Hi...
I don't know much about ASP.NET (yet), but I do know about polymorphism...
The code in listing 10-7 (and subsequent listings where the same technique is used), are not using the atomized strings...
From listing 10-7:
Code:
NameTable nt = new NameTable();
object book = nt.Add( "book" );
...
if ( ... && book.Equals( reader.LocalName ) )
The
Add() method returns a
string. So, the
book variable, even though it's of type
object, references a string object.
Since
string overrides the
Equals() method, the comparison will actually be a
string comparison, and not an object reference comparison, as was intended. Polymorphism will cause the
string override of
Equals() to be called.
What the code
should be in order to optimize it with the use of atomized strings is:
Code:
if ( ... && ReferenceEquals( book, reader.LocalName ) )
ReferenceEquals() is implemented by
System.Object and compares the object references.
book is a reference to the atomized string, so it will actually be compared to the atomized
Reader.LocalName object reference.
David
Including NameTable Optimization (page 513)
