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Making the objects distinguishable

After the code in Listing 3 has been executed, the buttons and labels are indistinguishable on the basis of the null value of their toolTipText property.

The code in Listing 4 deals with this issue. This code uses the setToolTipText method to store a unique String value in the toolTipText property of the object referred to by each of the elements in the collection.

Listing 4 . Making the objects distinguishable.
Iterator iter = ref.iterator(); int cnt = 0;JComponent refVar; while(iter.hasNext()){refVar = (JComponent)iter.next(); if(refVar instanceof JButton){refVar.setToolTipText("B"+cnt++); }else{refVar.setToolTipText("L" + cnt++); }//end else}//end while loop }//end fillIt()

Identifying the buttons and labels

In addition to storing a unique value in the toolTipText property of the object referred to by each element, the code in Listing 4 also makes it possible to distinguish between the JButton objects and the JLabel objects. This is accomplished by including an upper-case "B" in the propertyvalue for each JButton , and including an upper-case "L" in the property value for each JLabel button.

Why populate this way?

This approach to population is, admittedly, a little bit of an overkill for illustrating what I want to illustrate in this program. However, I plan to usethe same fillIt method in the sample program in the next module, and it won't be an overkill there.

Display the collection

The code in Listing 2 above calls the showCollection method to display the contents of the populated LinkedList collection. The showCollection method is shown in Listing 5

Listing 5 . The showCollection method.
void showCollection(Collection ref){ Iterator iter = ref.iterator();while(iter.hasNext()){ System.out.print(((JComponent)iter.next()).getToolTipText() + " "); }//end while loopSystem.out.println(); }//end showCollection

By now, you should have no difficulty understanding the code in Listing 5 . This code gets an iterator on the incoming reference of type Collection . The code then uses that iterator to gain access to each element in succession,displaying the String value of the toolTipText property belonging to a particular object during each iteration.

Downcast is required

Note that the next method of the Iterator interface returns a reference to the next element in the collection, as type Object . (Remember, Generics were not used to populate this collection.)

In order to call the getToolTipText method on the returned reference, the reference must be downcast to type JComponent . Since both JButton and JLabel extend JComponent , and the getToolTipText method is declared in the JComponent class, it is not necessary to be concerned as to whether an object is type JButton or type JLabel to display the value of the toolTipText property. (This is an example of polymorphic behavior based on class inheritance.)

The output for the collection

The output produced by the code in Listing 2 is shown below:

Collection contentsB0 B1 L2 B3 B4 L5

By examining the "B" and "L" characters in this output, you can identify the JButton objects and the JLabel objects.

Questions & Answers

do you think it's worthwhile in the long term to study the effects and possibilities of nanotechnology on viral treatment?
Damian Reply
absolutely yes
how to know photocatalytic properties of tio2 nanoparticles...what to do now
Akash Reply
it is a goid question and i want to know the answer as well
characteristics of micro business
Do somebody tell me a best nano engineering book for beginners?
s. Reply
what is fullerene does it is used to make bukky balls
Devang Reply
are you nano engineer ?
fullerene is a bucky ball aka Carbon 60 molecule. It was name by the architect Fuller. He design the geodesic dome. it resembles a soccer ball.
what is the actual application of fullerenes nowadays?
That is a great question Damian. best way to answer that question is to Google it. there are hundreds of applications for buck minister fullerenes, from medical to aerospace. you can also find plenty of research papers that will give you great detail on the potential applications of fullerenes.
what is the Synthesis, properties,and applications of carbon nano chemistry
Abhijith Reply
Mostly, they use nano carbon for electronics and for materials to be strengthened.
is Bucky paper clear?
so some one know about replacing silicon atom with phosphorous in semiconductors device?
s. Reply
Yeah, it is a pain to say the least. You basically have to heat the substarte up to around 1000 degrees celcius then pass phosphene gas over top of it, which is explosive and toxic by the way, under very low pressure.
Do you know which machine is used to that process?
how to fabricate graphene ink ?
for screen printed electrodes ?
What is lattice structure?
s. Reply
of graphene you mean?
or in general
in general
Graphene has a hexagonal structure
On having this app for quite a bit time, Haven't realised there's a chat room in it.
what is biological synthesis of nanoparticles
Sanket Reply
what's the easiest and fastest way to the synthesize AgNP?
Damian Reply
types of nano material
abeetha Reply
I start with an easy one. carbon nanotubes woven into a long filament like a string
many many of nanotubes
what is the k.e before it land
what is the function of carbon nanotubes?
I'm interested in nanotube
what is nanomaterials​ and their applications of sensors.
Ramkumar Reply
what is nano technology
Sravani Reply
what is system testing?
preparation of nanomaterial
Victor Reply
Yes, Nanotechnology has a very fast field of applications and their is always something new to do with it...
Himanshu Reply
good afternoon madam
what is system testing
what is the application of nanotechnology?
In this morden time nanotechnology used in many field . 1-Electronics-manufacturad IC ,RAM,MRAM,solar panel etc 2-Helth and Medical-Nanomedicine,Drug Dilivery for cancer treatment etc 3- Atomobile -MEMS, Coating on car etc. and may other field for details you can check at Google
anybody can imagine what will be happen after 100 years from now in nano tech world
after 100 year this will be not nanotechnology maybe this technology name will be change . maybe aftet 100 year . we work on electron lable practically about its properties and behaviour by the different instruments
name doesn't matter , whatever it will be change... I'm taking about effect on circumstances of the microscopic world
how hard could it be to apply nanotechnology against viral infections such HIV or Ebola?
silver nanoparticles could handle the job?
not now but maybe in future only AgNP maybe any other nanomaterials
I'm interested in Nanotube
this technology will not going on for the long time , so I'm thinking about femtotechnology 10^-15
how did you get the value of 2000N.What calculations are needed to arrive at it
Smarajit Reply
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