Solved

Is my understanding of a generic method correct?

Posted on 2011-09-11
9
300 Views
Last Modified: 2012-05-12
I'm trying to summarize for myself what a generic method is. Am I correct here?

Let's say you are implementing a method that accepts a collection of objects and sorts the objects. The method signature specifies the specific type of object you will be storing in the collection. Let's say the method takes "Collection<myType>" as its parameter. You can call this method with any collection whose element type in this collection is a parent of myType. This is an example of a generic method.
0
Comment
Question by:shampouya
  • 5
  • 4
9 Comments
 
LVL 47

Expert Comment

by:for_yan
ID: 36518571
you can call this method with any collection of object either of myType or of type inherited from myType.
So if myType is Object you can call with  the Collection of String.
This is because it meas in your method you may be using methods of myType, and you may rely that any objects which inherit form myType
do have methods of myType class.
0
 

Author Comment

by:shampouya
ID: 36518595
So if the method took "Collection<Object>" as it's parameter, then a collection of String could be passed as the argument, because String is a child of Object. Am I correct?
0
 
LVL 47

Expert Comment

by:for_yan
ID: 36518597
Yes, you are correct.
0
Announcing the Most Valuable Experts of 2016

MVEs are more concerned with the satisfaction of those they help than with the considerable points they can earn. They are the types of people you feel privileged to call colleagues. Join us in honoring this amazing group of Experts.

 
LVL 47

Expert Comment

by:for_yan
ID: 36518601
The ooposite would not work:

imagine I have a method which  relies on collection of Strings
It means that it may well happened theat somewhere inside the method
I may extract some element and say use method substring() of the String elelment

Now if you passed me collection of Objects - these elemets will not have such method as subvstring()  - so the method cannot work for such collection
0
 
LVL 47

Expert Comment

by:for_yan
ID: 36518607
However String has all those methods which Object has,
therefore if my method was devised for a collection of Objects - it means inside the method I could only apply to lelements of the collection only methods of class Object.
So if I now pass collection of Strings to thuis method everything will workbecause Strinngs do have all those methods which Objects have - so no problem may arise -
metods declared for Collection of Objects will worjk for collection of Strings also.
0
 

Author Comment

by:shampouya
ID: 36518615
Ok that makes sense. So can I think of a generic method as a method that:

a) takes type parameters
b) has the type specified in the angled brackets <> within the method signature
c) expects "exampleType" to be in its parameters but it will also accepts any children of exampleType because they inherit from exampleType

Am I correct here?
0
 
LVL 47

Accepted Solution

by:
for_yan earned 500 total points
ID: 36518618
Yes, you are correct
0
 

Author Comment

by:shampouya
ID: 36518626
wow that was easy
0
 

Author Closing Comment

by:shampouya
ID: 36518628
thanks
0

Featured Post

Announcing the Most Valuable Experts of 2016

MVEs are more concerned with the satisfaction of those they help than with the considerable points they can earn. They are the types of people you feel privileged to call colleagues. Join us in honoring this amazing group of Experts.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Suggested Solutions

Title # Comments Views Activity
HSSFWorkbook cannot be resolved error 10 64
servlet doXXX methods 3 47
split string containing \r\n in Java 46 43
expectj telnet failing 5 35
For beginner Java programmers or at least those new to the Eclipse IDE, the following tutorial will show some (four) ways in which you can import your Java projects to your Eclipse workbench. Introduction While learning Java can be done with…
Java Flight Recorder and Java Mission Control together create a complete tool chain to continuously collect low level and detailed runtime information enabling after-the-fact incident analysis. Java Flight Recorder is a profiling and event collectio…
Viewers learn about the “for” loop and how it works in Java. By comparing it to the while loop learned before, viewers can make the transition easily. You will learn about the formatting of the for loop as we write a program that prints even numbers…
This tutorial will introduce the viewer to VisualVM for the Java platform application. This video explains an example program and covers the Overview, Monitor, and Heap Dump tabs.

815 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question

Need Help in Real-Time?

Connect with top rated Experts

12 Experts available now in Live!

Get 1:1 Help Now