http://tech.puredanger.com/2007/07/03/pattern-hate-template/ Alex Miller's technical blog Thu, 28 Aug 2008 03:19:26 +0000 http://wordpress.org/?v=2.0.2 http://tech.puredanger.com/2007/07/03/pattern-hate-template/#comment-49449 Tue, 20 May 2008 16:57:10 +0000 http://tech.puredanger.com/2007/07/03/pattern-hate-template/#comment-49449 [...] 2. Then, consider alternatives like strategy, factory or callback. http://tech.puredanger.com/2007/07/03/pattern-hate-template/ Posted 21 May 2008 / C_CPlusPlus / [...] […] 2. Then, consider alternatives like strategy, factory or callback. http://tech.puredanger.com/2007/07/03/pattern-hate-template/ Posted 21 May 2008 / C_CPlusPlus / […]

]]> http://tech.puredanger.com/2007/07/03/pattern-hate-template/#comment-44108 Wed, 30 Apr 2008 08:58:21 +0000 http://tech.puredanger.com/2007/07/03/pattern-hate-template/#comment-44108 [...] Having come across Alex Miller’s blog, I’ve enjoyed a number of his posts. However, whereas I am definitely in-line with his dislike of the Singleton pattern, I couldn’t agree with his conclusions on the use of the template pattern. 1. Communicates intent poorly - The template method pattern is often used as part of the effective API in some mini-framework where the framework user is expected to subclass the template class. My experience has been that it is difficult to communicate that usage intent to users of the framework. Often the template class has some non-private methods that are exposed for use by the framework but are not intended to be used by the framework user, some that are intended to be overridden, and some that are both. Also, you may need to say whether the super’s version of the method can, should, or must be called. Communicating all that clearly is impossible in an API of any complexity. [...] […] Having come across Alex Miller’s blog, I’ve enjoyed a number of his posts. However, whereas I am definitely in-line with his dislike of the Singleton pattern, I couldn’t agree with his conclusions on the use of the template pattern. 1. Communicates intent poorly - The template method pattern is often used as part of the effective API in some mini-framework where the framework user is expected to subclass the template class. My experience has been that it is difficult to communicate that usage intent to users of the framework. Often the template class has some non-private methods that are exposed for use by the framework but are not intended to be used by the framework user, some that are intended to be overridden, and some that are both. Also, you may need to say whether the super’s version of the method can, should, or must be called. Communicating all that clearly is impossible in an API of any complexity. […]

]]> http://tech.puredanger.com/2007/07/03/pattern-hate-template/#comment-34413 Tue, 25 Mar 2008 03:12:11 +0000 http://tech.puredanger.com/2007/07/03/pattern-hate-template/#comment-34413 I don't think this would be considered a template method pattern. Usually a template method is described as an algorithm with pluggable steps. Certainly abstract classes are useful. I don’t think this would be considered a template method pattern. Usually a template method is described as an algorithm with pluggable steps. Certainly abstract classes are useful.

]]> http://tech.puredanger.com/2007/07/03/pattern-hate-template/#comment-34195 Sun, 23 Mar 2008 18:45:23 +0000 http://tech.puredanger.com/2007/07/03/pattern-hate-template/#comment-34195 Little amendment to my todays post, as this just came to my mind about 5 minutes ago: Look at java collection api, to be precise to the AbstractXYZ classes. Read the header, for instance of AbstractList, which tells you about how simple it could be to implement a List...I think this is a good example of template-method pattern. Little amendment to my todays post, as this just came to my mind about 5 minutes ago: Look at java collection api, to be precise to the AbstractXYZ classes. Read the header, for instance of AbstractList, which tells you about how simple it could be to implement a List…I think this is a good example of template-method pattern.

]]> http://tech.puredanger.com/2007/07/03/pattern-hate-template/#comment-34150 Sun, 23 Mar 2008 13:36:43 +0000 http://tech.puredanger.com/2007/07/03/pattern-hate-template/#comment-34150 Just an amendment to my recent post, because it came to my mind about 5 minutes ago: A rather good real life example of template-pattern is the collection API, to be precise the AbstractXYZ impls, which I would say apply template method in a rather benefiting way: Take a look what http://java.sun.com/j2se/1.4.2/docs/api/java/util/AbstractList.html states in it javadoc header about implementation requirements for immutable or immutable lists. Just an amendment to my recent post, because it came to my mind about 5 minutes ago: A rather good real life example of template-pattern is the collection API, to be precise the AbstractXYZ impls, which I would say apply template method in a rather benefiting way: Take a look what http://java.sun.com/j2se/1.4.2/docs/api/java/util/AbstractList.html
states in it javadoc header about implementation requirements for immutable or immutable lists.

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