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For 2021 - online Python 3 training - see ((here)).

Our plans were to retire in summer 2020 and see the world, but Coronavirus has lead us into a lot of lockdown programming in Python 3 and PHP 7.
We can now offer tailored online training - small groups, real tutors - works really well for groups of 4 to 14 delegates. Anywhere in the world; course language English.

Please ask about private 'maintenance' training for Python 2, Tcl, Perl, PHP, Lua, etc.
Philosophy behind object design - and how I applied in to a Java example

* When you're writing all the logic to deal with a particular type of data, it's a good idea to write it into a CLASS

* Where you have similar types of data, it's a good idea to put the shared logic into a BASE CLASS and then write SUBCLASSES which are based on that base class. That way your common code is in one place, can be maintained easily and shared later on with any other subclasses too.

* When you write your code in classes, you can write a TEST PROGRAM to check that just the class works, thus segmenting your testing and getting a far easier regime, yet far more robust results

* Should you wish to have type of objects outside your "interitance tree" which perform in the same way as the object within the tree, you can declare that they conform to an INTERFACE.

* You can then write FURTHER PROGRAMS that use arrays of objects of classes which conform to the interface.

* And you can place all of the classes and the interface defintion into a package and bundle them up together for distribution and use into a single jar file.




I did the above in Java today.

There's a base class called Bird - [here]. It's desribed as an abstarct class because it only contains common logic - not the full definition of a bird, as that's completed in the next classes.

There are subclasses for Duck and Gull - [here] and [here].

There's a first program that creates and uses a duck and a gull object and extracts data from them - [here]

I then defined an interface called Friend - that's [here].

And finally, my example that uses an array of friends - in my simple example they're all birds, but I can have friend who aren't birds too provided that they conform to the interface which requires them to return a greeting when their greet method is called. See [here].

(written 2015-01-14, updated 2015-01-15)

 
Associated topics are indexed as below, or enter http://melksh.am/nnnn for individual articles
Q909 - Object Orientation and General technical topics - Object Orientation: Composite Objects
  [477] Class, static and unbound variables - (2005-10-25)
  [592] NOT Gone phishing - (2006-02-05)
  [1345] Perl and Shell coding standards / costs of an IT project - (2007-09-11)
  [1348] Screw it or Glue it? Access to Object variables - a warning - (2007-09-12)
  [2170] Designing a heirarcy of classes - getting inheritance right - (2009-05-11)
  [2641] Object Oriented Programming in PHP - (2010-02-19)
  [2865] Relationships between Java classes - inheritance, packaging and others - (2010-07-10)
  [2922] Getting the OO design write - with PHP a example - (2010-08-14)
  [3142] Private and Public - and things between - (2011-01-22)
  [3152] Jargon busting - (2011-01-30)
  [3251] C++ - objects that are based on other objects, saving coding and adding robustness - (2011-04-17)
  [3609] How do classes relate to each other? Associated Classes - (2012-02-12)
  [3979] Extended and Associated objects - what is the difference - C++ example - (2013-01-18)
  [4377] Designing a base class and subclasses, and their extension, in C++ - (2015-01-01)
  [4450] Deciding whether to use parameters, conditional statements or subclasses - (2015-03-05)

J710 - Java - Extending Classes and More
  [656] Think about your design even if you don't use full UML - (2006-03-24)
  [831] Comparison of Object Oriented Philosophy - Python, Java, C++, Perl - (2006-08-13)
  [1066] Final, Finally and Finalize - three special words in Java - (2007-02-05)
  [1217] What are factory and singleton classes? - (2007-06-04)
  [1294] An example of Java Inheritance from scratch - (2007-08-00)
  [1501] Java - using super to call a method in the parent class - (2008-01-10)
  [1538] Teaching Object Oriented Java with Students and Ice Cream - (2008-02-12)
  [1556] Java - a demonstration of inheritance on just one page - (2008-02-26)
  [1819] Calling base class constructors - (2008-10-03)
  [2185] Abstract Classes - Java - (2009-05-16)
  [2434] Abstract classes, Interfaces, PHP and Java - (2009-10-03)
  [2604] Tips for writing a test program (Ruby / Python / Java) - (2010-01-29)
  [2860] What methods are available on this Java object? - (2010-07-08)
  [3047] What is a universal superclass? Java / Perl / Python / Other OO languages - (2010-11-13)
  [4334] Splitting out code into name blocks for clarity and reusability - (2014-11-30)
  [4366] Changing what operators do on objects - a comparison across different programming languages - (2014-12-26)
  [4419] Java Inheritance example - group of classes - step by step - (2015-02-08)
  [4422] Objects - from physical to virtual or abstract - Java - (2015-02-10)

J801 - Review of Java Basics
  [1082] Straight from the .jar - (2007-02-16)


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Some other Articles
Accessing variables across subroutine boundaries - Perl, Python, Java and Tcl
TransWilts / Press and Publicity report for AGM / 30th January 2015
Java Utility class - flexible replacement for array. Also cacheing in objects and multiple catch clauses example.
Preparing data through a little bit of Perl
Philosophy behind object design - and how I applied in to a Java example
Splitting Java strings and extracting numbers
Interview conditions,and other instructions to staff
Refactoring Perl applications to give them a rosy future
Checking MySQL database backups have worked (not failed)
Cucumber example - test::unit, scenario outlines, datafile driven test
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This is a page archived from The Horse's Mouth at http://www.wellho.net/horse/ - the diary and writings of Graham Ellis. Every attempt was made to provide current information at the time the page was written, but things do move forward in our business - new software releases, price changes, new techniques. Please check back via our main site for current courses, prices, versions, etc - any mention of a price in "The Horse's Mouth" cannot be taken as an offer to supply at that price.

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