Databases
StackOverflow2013
Postsdbo
POAn obvious singleton implementation for .NET?
 

Note that there are some explanatory texts on larger screens.

plurals
  1. POAn obvious singleton implementation for .NET?
    primarykey
    data
    text
    <p>I was thinking about the classic issue of lazy singleton initialization - the whole matter of the inefficiency of:</p> <pre><code>if (instance == null) { instance = new Foo(); } return instance; </code></pre> <p>Anyone who knows what a Singleton is is familiar with the issue(you only need the if once). It's trivial but irritating.</p> <p>So, I thought of an alternate solution, at least for .NET(although it should work anywhere that has some equivalent to function pointers:</p> <pre><code>public class Foo { private delegate Foo FooReturner(); private static Foo innerFoo; private static FooReturner fooReturnHandler = new FooReturner(InitialFooReturner); public static Foo Instance { get { return fooReturnHandler(); } } private static Foo InitialFooReturner() { innerFoo = new Foo(); fooReturnHandler = new FooReturner(NewFooReturner); return innerFoo; } private static Foo NewFooReturner() { return innerFoo; } } </code></pre> <p>In short - the Instance returns a delegate method. The delegate is initially set to a method that initializes your instance, then changes the delegate to point at a simple Return method.</p> <p>Now, I like to think I'm not terrible at my job, but I have no pretensions about being awesome. I have not seen an example of this code anywhere.</p> <p>Ergo, I come to the conclusion that I am missing something. Something major. Either that the whole problem is too trivial to bother thinking that much about or this does something horrible that will destroy the universe. Or I fail at searching and therefore haven't seen the hundreds of developers using this method. Something, anyway.</p> <p>I was hoping the good folks here at Stack Overflow could clue me in as to what(leaving aside the controversy on whether one should use a Singleton at all).</p> <p>EDIT for clarification:</p> <p>This is not performance code(although if the design actively degrades performance beyond the traditional model, that would be interesting to know). </p> <p>It was written purely as proof-of-concept, and I am further aware that it is not thread-safe as it properly should be. Is there any reason why it could NOT be made thread-safe by it's very nature? </p>
    singulars
    1. PO
      singulars
      1. PTAnswer
    1. This table or related slice is empty.
    1. PTQuestion
    1. USFaqa
    1. USFaqa
    plurals
    1. PL
      singulars
      1. LTLinked
    1. PL
      singulars
      1. LTLinked
    2. PL
      singulars
      1. LTLinked
    3. PL
      singulars
      1. LTLinked
    1. This table or related slice is empty.
    1. PO
      singulars
      1. PTAnswer
    2. PO
      singulars
      1. PTAnswer
    3. PO
      singulars
      1. PTAnswer
    1. VO
      singulars
      1. POAn obvious singleton implementation for .NET?
      1. USSixOThree
      1. VTFavorite
    2. VO
      singulars
      1. POAn obvious singleton implementation for .NET?
      1. This table or related slice is empty.
      1. VTUpMod
    3. VO
      singulars
      1. POAn obvious singleton implementation for .NET?
      1. This table or related slice is empty.
      1. VTUpMod
    1. CO"inefficiency" - I'd worry more that it isn't actually thread-safe ;-p
      singulars
      1. POAn obvious singleton implementation for .NET?
      1. USMarc Gravell
    2. CORe the edit... but it adds complexity, and doesn't address any issue... why would you choose this over just a null check? If you want to fix the thread safety, read Jon's page...
      singulars
      1. POAn obvious singleton implementation for .NET?
      1. USMarc Gravell
    3. CO+1 "Universe destruction" hypothesis. :P Apart from that, good question, and faved for the record.
      singulars
      1. POAn obvious singleton implementation for .NET?
      1. USOlivier Tremblay
 

Querying!

 
Guidance
A row detail

Detail views are divided into sections. All the information in the data section comes from columns in the selected row. The other sections display data from other, related rows.

Related data can be related in a to-one or a to-many fashion. Captions of data related in a to-many fashion link to a list view showing a filtered view of the table.

Try moving around until you find a non-empty to-many entry and click on the label to get to one. You can move back to the root by clicking on the database name in the header.

SQuiL has stopped working due to an internal error.

If you are curious you may find further information in the browser console, which is accessible through the devtools (F12).

Reload