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From: Robert Klemme <shortcutter@googlemail.com>
Newsgroups: comp.lang.java.programmer
Subject: Re: Class.forName().newInstance() vs new
Date: Sun, 12 Jun 2011 14:14:10 +0200
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On 06/11/2011 09:43 PM, John B. Matthews wrote:
> In article<it0brg$s3t$2@speranza.aioe.org>,
>   Abu Yahya<abu_yahya@invalid.com>  wrote:
>
>> Could you give an example of how the factory method might look like?
>
> There's some good examples here:
>
> <http://en.wikipedia.org/wiki/Factory_method_pattern>
>
> And in the linked article, "Item 1: Consider static factory methods
> instead of constructors."
>
> <http://drdobbs.com/java/208403883?pgno=1>

If Class.forName() is the bottleneck then a static factory method does 
not help in this particular case.  You would have to configure the 
method name or a class name anyway and use reflection to get at the 
instance or method.

Abu, to answer your question (pseudo code):

interface com.your.company.db.DbManager {
  // methods
}

interface com.your.company.db.DbManagerFactory {
   DbManager create(/* args if needed */) throws WhateverException
}

class com.your.company.db.ora.OraDbManager implements DbManager {
   // ...
}

class com.your.company.db.ora.OracleDbManagerFactory implements 
DbManagerFactory {
   public DbManager create() {
     return new OraDbManager();
   }
}


Kind regards

	robert