Some Coding Considerations

1
Some Coding Considerations
2
Collection Classes

• Use the collection classes in the java.util
  package.
• The type declaration should refer to the
  interface, not the implementation.
• Yes
• import java.util.List
• . . .
• List views new ArrayList()
• No
• ArrayList views new ArrayList()

3
Collection Iteration Idioms

• For standard collection instance, c
• for (Iterator i c.iterator() i.hasNext )
• doSomething( i.next() )
• For high-performance iteration over random access
  list, list
• for ( int i 0, n list.size() i lt n i)
• doSomething( list.get(i) )

4
Implementation Order

• For acyclic classes, implement/test classes
  bottom-up.
• The figure is an example.
• Arcs represent uses relation
• Node numbers indicate an ordering.

5
Implementation Order

• For cyclic classes,
• test nodes referring to each other at the same
  time.
• or
• Test aspects of 4 that do not refer to 5
• Test aspects of 5 that do not refer to 4.
• Test aspects of 4 that refer to 5.
• Test aspects of 5 that refer to 4.

7
6
5
3
4
1
2
6
Test-First

• The general class development algorithm is
  approximately as follows
• while ( ! class.isComplete )
• write a little test code
• write the corresponding production code

7
Testing

• Keep a classs unit test code in either
• The classs main method
• Quick simple
• Not optimized for regression testing
• Increases classs size, even when not testing.
• A separate class.
• Our Resources page links to http//www.junit.org/.
  
• The Junit Cookbook.