Groovy Day 3 : operators overloading

Back in 2009, when I learned C# for a Microsoft Contest (Imagine Cup) I was wondering why Java has no operator overload mechanisms. After discussion and thinking, the problems are the readability and possible deratives. Firstly the readability because it could disturb the newbies when they see a code where an element is added to a list using a +=. It is not always clear, depending on the language, which method is called internally. The second problem comes from the first one in some sense. You could imagine a new way of code obscuration when you implement the addition with a minus symbol or the append on String with a division symbol. Just imagine the chaos that could appear.

Groovy resolves the first problem by giving a limited set of symbol that can be overload. For example, the constructor operator cannot be overloaded. This limited choice reduces the potential mistakes. Then Groovy provides by its JDK (Java development kit) some common operators that follow standards. Additionally  the operators are linked to named methods, this provide a certain security for the new developers. They could easily use the normal methods to do their stuff.
Stop the theory, let's show some examples !

// initialization of a list using Groovy facilities
List list = []
// append 'hello' to the list
list.add('hello')
// without parenthesis this time
list.add 'world'
// using leftShift method
list.leftShift('too')
// using the symbol leftShift
list << 'other'

assert list == ['hello', 'world', 'too', 'other']

Groovy Day 2 : Differences in term of readability between Java and Groovy

For this article, we will see the differences of readability between an "old" language (Java) and a dynamic language (Groovy). You will see at first the evolution of Java to try to become more readable for the novice (and less tiring for the advance developper). The second part is the Groovy version of the same code and you will see the difference very easily.
I decided to use a simple example of a creation of HashMap and store in it the names of the seasons and the related adjectives.

First code snippet is a Java 1.4 code.

class HashMapJavaShow {
   public static void main(String[] args) {
      // creation of the hashmap
      HashMap<String, String> seasons = new HashMap<String, String>();
      
      // insertion of data, key => value
      // in this example we take the name of the season as key
      // and the related adjective as value
      seasons.put("spring", "vernal");
      seasons.put("summer", "estival");
      seasons.put("automn", "autumnal");
      seasons.put("winter", "hibernal");
      
      // before 1.5 we were forced to use an iterator
      Iterator iter = seasons.iterator();
      // loop until the iterator has not more element
      while(iter.hasNext()){
         // retrieve the current element and display it
         // using its default method toString()
         System.out.println(iter.next());
      }
   }
}