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Singleton Pattern & its usageHi,
I am new to this forum and the topics of Design pattern. I am interested in know where the Singleton pattern is applicable and where it is useful. Thanks, Harshad Riswadkar, Mar 29, 2010
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Reply 1Recently I used a Singleton Pattern in one of my projects. Find the excerpt of the constraints as below. I had to develop a Windows service to download data from a Mainframe database for individual entities and create MS Access files from these. I had only read access to the AS400. Also if the Windows services is restarted, it needed to continue from where it left off. So, I needed a datastore to keep track of my Windows service processing.
Since I needed to use an XML datastore which was accessed concurrently by multiple threads, I could have only one instance of my XML file in memory at any given point of time. Therefore, I decided to use the Singleton pattern here. In addition, we used locks and synchonizing objects within the Singleton. Sreenivas Manyam Rajaram, Apr 23, 2010
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Reply 2Hi,
The constructor of the class gets execute only ONCE in the lifecycle. Then the single instance can serve all the request. One can easilt implement this using LOCK. -- Kaushal http://kaushalp.blogspot.com Kaushal Patel, Apr 14, 2010
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Reply 3I used Singleton to open just one winform at a same time via a menu. When user clicks the menu item again, if the form was already open, it doesn't create another form and just display the current one.
Cheers, Hamid Hamid Ghader, Apr 08, 2010
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Reply 4I would use singleton only, if the usage is some kind of stateless - otherwise you will have problems with testing (thats why singleton and static sometimes can suck if they are used in the wrong context
The Saint, Apr 08, 2010
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Reply 5Well this can extend on to a single instance of the application as opposed to single instance of a class. In those cases you may have to use classes like Mutex and Registry to achieve your objective
Sriram Krishnan, Apr 05, 2010
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Reply 6Singleton pattern is used where you need to create only single instance for whole application. Lets take example of session counter of site I will create only single object of session counter and change counters when user create session or close it. No need to create new object in this case. here I will use singleton design pattern for creating object. For singleton class example in .net you can check link below
http://www.dotnetpal.com/pattern/singleton.htm Ashish Sharma, Mar 31, 2010
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