Adaptive Software Solutions

I am reading the excellent Django book right now. In the 4th chapter on Django templates , there is an example of includes and inheritance in Django templates. Without going into details about Django templates, the include is very similar to composition where we can include the text of another template for evaluation. Inheritance in Django templates works in a way similar to object inheritance. Django templates can specify certain blocks which can be redefined in subtemplates. The subtemplates use the rest of the parent template as is. Now we have all learned that inheritance is used when we have a is-a relationship between classes, and composition is used when we have a contains-a relationship. This is absolutely right, but while reading about Django templates, I just realized another pattern in these relationships. This is really simple and perhaps many of you may have already have had this insight... We use inheritance when we want to allow reuse of the bulk of one object in other

Groovy has done a great job of enhancing Java Strings. It offers a lot of features like String interpolation with GStrings, triple quoted Strings, multi-line Strings, and slashy Strings. In this post I will talk about slashy Strings in Groovy. But before doing that let us see how we represent a regular expression in Java. Let's say I have a list of fully qualified file names and I want to match all files in my 'c:\tmp' directory. I would create a String to represent my regex in Java like this: String exp = "C:\\\\tmp\\\\.*" The four '\' are needed because '\' is a meta character in regular expressions, so we need to represent a '\' as a '\\'. Because a '\' is used for escaping special characters in Java, we need to represent '\\' as '\\\\'. Wow doesn't this look cumbersome. Well, this is not just one case. Regular expressions make use of the '\' character for special classes. Everytime we want to