Appendix B: Comparing C++ and Java 823 47...

Odnośniki

Smutek to uczucie, jak gdyby się tonęło, jak gdyby grzebano cię w ziemi.
Some Java ORB products offer proprietary solutions to this problem...
The Arrays class has another sort( ) method that takes a single argument: an array of Object, but with no Comparator...
// {Args: 500} import java...
- Jakkolwiek będzie - powiedział do Kathi Logan i do każdego, kto go słuchał - zamierzam stanąć w słońcu tak, aby to przeszkadzało tym ludziom w odszukaniu mnie...
Zjadł dwie parówki i wypił karafkę wina w kawiarni na rynku...
- Ależ, milady, to nie przystoi, żebyśmy zasiedli do stołu z lepszymi od siebie...
wać w raportach...
niezrozumiałe szczegóły zawarte w tre ci rzeczonych przywilejów nabior ja niejszego znaczenia i zatrac wszelk niepewno wyra enia dwuznaczne, skutkiem...
Falą i nagą stopą, co wnet się zanurzy, Przyjściem listu i zdjęciem pieczęci z pośpiechem, Pomiędzy zaproszeniem i rankiem podróży, Między...
sem miały się stać ważnym narzędziem wpOlityce rodów magnackich...

Smutek to uczucie, jak gdyby się tonęło, jak gdyby grzebano cię w ziemi.

Generally, Java is more robust, via:
– Object handles initialized to null (a keyword)
– Handles are always checked and exceptions are thrown for failures
– All array accesses are checked for bounds violations
– Automatic garbage collection prevents memory leaks
– Clean, relatively fool-proof exception handling
– Simple language support for multithreading
– Bytecode verification of network applets
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Thinking in Java
www.BruceEckel.com
K
C: Java programming
guidelines
This appendix contains suggestions to help guide you while performing
low-level program design, and also while writing code.
1. Capitalize the first letter of class names. The first letter of fields, methods, and objects (handles) should be lowercase. All identifiers should run their words together, and capitalize the first letter of all intermediate words. For example:
ThisIsAClassName
thisIsAMethodOrFieldName
Capitalize all the letters of static final primitive identifiers that have constant initializers in their definitions. This indicates they are compile-time constants.
Packages are a special case: they are all lowercase letters, even for intermediate words.
The domain extension (com, org, net, edu, etc.) should also be lowercase. (This was a change between Java 1.1 and Java 1.2.)
2. When creating a class for general-purpose use, follow a “canonical form” and include definitions for equals( ), hashCode( ), toString( ), clone( ) (implement Cloneable), and implement Serializable.
3. For each class you create, consider including a main( ) that contains code to test that class. You don’t need to remove the test code to use the class in a project, and if you make any changes you can easily re-run the tests. This code also provides examples of how to use your class.
4. Methods should be kept to brief, functional units that describe and implement a discrete part of a class interface. Ideally, methods should be concise; if they are long you might want to search for a way to break them up into several shorter methods. This will also 825
foster reuse within your class. (Sometimes methods must be large, but they should still do just one thing.)
5. When you design a class, think about the client programmer’s perspective (the class should be fairly obvious to use) and the perspective of the person maintaining the code (anticipate the kind of changes that will be made, to make them easy).
6. Try to keep classes small and focused. Clues to suggest redesign of a class are: 1) A complicated switch statement: consider using polymorphism
2) A large number of methods that cover broadly different types of operations: consider using several classes
3) A large number of member variables that concern broadly different characteristics: consider using several classes
7. Keep things as “private as possible.” Once you publicize an aspect of your library (a method, a class, a field), you can never take it out. If you do, you’ll wreck somebody’s existing code, forcing them to rewrite and redesign. If you publicize only what you must, you can change everything else with impunity, and since designs tend to evolve this is an important freedom. Privacy is especially important when dealing with multithreading – only private fields can be protected against un-synchronized use.
8. Watch out for “giant object syndrome.” This is often an affliction of procedural programmers who are new to OOP and who end up writing a procedural program and sticking it inside one or two giant objects. With the exception of application frameworks, objects represent concepts in your application, not the application.
9. If you must do something ugly, at least localize the ugliness inside a class.
10. Anytime you notice classes that appear to have high coupling with each other, consider the coding and maintenance improvements you might get by using inner classes (see
“Improving the code with an inner class” on page 605).
11. Use comments liberally, and use the javadoc comment-documentation syntax to produce your program documentation.
12. Avoid using “magic numbers,” which are numbers hard-wired into code. These are a nightmare if you need to change them, since you never know if “100” means “the array size” or “something else entirely.” Instead, create a constant with a descriptive name and use the constant identifier throughout your program. This makes the program easier to understand and much easier to maintain.