PI 7.1 Adapter Module - meaning of VERSION_ID and serialVersionUID?

Question

Hi!
I am currently developing my first PI Adapter Module. In SAP sample coding GetHostName I find the following declarations and I ask me what's the meaning and/or purpose of these declarations:
public static final String VERSION_ID = "$Id://tc/aii/30_REL/src/_adapters/_sample/java/user/module/GetHostName.java#1 $";
satic final long serialVersionUID = 7435850550539048631L;
And additionally how I have to declare these two variables for my adapter module ... This comes true especially for VERSION_ID, because serialVersionUID can be generated by NWDS using quick fix feature. It then declares such a variable ...
Thanxs for any hint in advance!
Regards,
Volker

Answer 1

Hi Pavel,
public - this is the visibility modifier (it means that the body method can be call by any outside method)
static - the method is a static instance of the class. Not sure what exactly it does though.
final indicates that the value of the variable won't change - in other words, a variable who's value can't be modified after it is declared.
Use public final static String when you want to create a String that belongs to the class (no instance necessary to use it), and that won't change, for instance when you want to define a Stringconstant that will be available to all instances of the class, and to other objects using the class, depending on the access modifier:
public final static String MY_CONSTANT = "SomeValue";  // ... in some other code, possibly in another object, use the constant: if (input.equals(MyClass.MY_CONSTANT)
All the variables are implicitly public static final in a Java Interface.
Is it a good coding practice to use public static final in constant variable although it is declared inside an Interface.
For example :
public interface TestInterface{  public static final String EX_CONSTANT = "ABC"; public static final int EX_INT_CONSTANT = 5; public static final double EX_DOUBLE = "5.0"; public static final Integer EX_INTEGER = 10;  }
Refer below links
http://scn.sap.com/community/pi-and-soa-middleware/blog/2012/09/24/setting-queue-dynamically-using-adapter-module
http://f0j00fec.benxbrain.com/en(bD1lbiZjPTAwMQ==)/index.do?onInputProcessing(brai_object_thread)&001_threadid=89626&001_boardtype=01&sysid=PI1&pgmid=R3TR&object=DTEL&obj_name=VERSION_ID&child_param=
Hope it will helpful..
Regards
Bhargava krishna