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Collection is an interface

The TreeSet class implements the SortedSet interface, which extends the Set interface, which in turn extends the Collection interface. Thus, a TreeSet object is a Collection . Therefore, a reference to a TreeSet object can be stored in a reference variable of type Collection , and can be treated as the generic type Collection .

What is a TreeSet object?

Among other things, in CS2 courses, we worry about the time and memory cost of a collection. According to Sun, the TreeSet class guarantees that the sorted set will be in ascending element order, and provides guaranteed log(n)time cost for the basic operations ( add , remove and contains ).

What does ascending element order mean?

Again, according to Sun, the elements will be sorted according to the natural order of the elements (see the Comparable interface) or by a comparator (see the Comparator interface) provided at the time the set is created. This depends on which overloaded constructor is used. I will have moreto say about these alternatives in a future module.

What does log(n) time cost mean?

I'm not going to try to explain the details of log(n) time cost here. Suffice it to say that the add , remove , and contains methods execute very fast. (I will have more to say about this is a future module.)

A TreeSet object is a Set

An object of the TreeSet class also is a Set . One of the characteristics of a Java Set (an object that implements the Set interface) is that it can contain no duplicate elements. Therefore, a TreeSet object can contain no duplicate elements. If the add method of a TreeSet object is called in an attempt to add a duplicate element, the element will not be added.

A TreeSet object is a SortedSet

The TreeSet class also implements the SortedSet interface. This guarantees that the contents of a TreeSet object will be in ascending element order, regardless of the order in which the elements are added. (In a future module, I will discuss how comparisons are made to enforce theordering of the elements.)

A TreeSet object is a Collection

Because an object of the TreeSet class is a Collection , a reference to such an object can be passed to any method that requires anincoming parameter of type Collection . The receiving method can call anymethod on that reference that is declared in the Collection interface . (I will discuss such methods in detail in future modules.)

Populate the Collection

The statement in Listing 2 passes the TreeSet object's reference to a method named fillIt , which is a static method of the Populator class. (The Populator class is a class of my own design whose only purpose is to illustrate the polymorphic behavior achieved using the CollectionsFramework.) The behavior of this method is to add elements to the incoming Collection object without regard for the actual type of the object (the class from which the object was instantiated).

Listing 2 . Populate the collection.
Populator.fillIt(ref);

At this point, I am going to discuss the fillIt method of the Populator class called in Listing 2 . The entire class definition of the Populator class, including the fillit method, is shown in Listing 3 .

Questions & Answers

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 ?
s.
what is the Synthesis, properties,and applications of carbon nano chemistry
Abhijith Reply
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.
Harper
how to fabricate graphene ink ?
SUYASH Reply
for screen printed electrodes ?
SUYASH
What is lattice structure?
s. Reply
of graphene you mean?
Ebrahim
or in general
Ebrahim
in general
s.
Graphene has a hexagonal structure
tahir
On having this app for quite a bit time, Haven't realised there's a chat room in it.
Cied
what is biological synthesis of nanoparticles
Sanket Reply
what's the easiest and fastest way to the synthesize AgNP?
Damian Reply
China
Cied
types of nano material
abeetha Reply
I start with an easy one. carbon nanotubes woven into a long filament like a string
Porter
many many of nanotubes
Porter
what is the k.e before it land
Yasmin
what is the function of carbon nanotubes?
Cesar
I'm interested in nanotube
Uday
what is nanomaterials​ and their applications of sensors.
Ramkumar Reply
what is nano technology
Sravani Reply
what is system testing?
AMJAD
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
AMJAD
what is system testing
AMJAD
what is the application of nanotechnology?
Stotaw
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
Azam
anybody can imagine what will be happen after 100 years from now in nano tech world
Prasenjit
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
Azam
name doesn't matter , whatever it will be change... I'm taking about effect on circumstances of the microscopic world
Prasenjit
how hard could it be to apply nanotechnology against viral infections such HIV or Ebola?
Damian
silver nanoparticles could handle the job?
Damian
not now but maybe in future only AgNP maybe any other nanomaterials
Azam
Hello
Uday
I'm interested in Nanotube
Uday
this technology will not going on for the long time , so I'm thinking about femtotechnology 10^-15
Prasenjit
can nanotechnology change the direction of the face of the world
Prasenjit Reply
At high concentrations (>0.01 M), the relation between absorptivity coefficient and absorbance is no longer linear. This is due to the electrostatic interactions between the quantum dots in close proximity. If the concentration of the solution is high, another effect that is seen is the scattering of light from the large number of quantum dots. This assumption only works at low concentrations of the analyte. Presence of stray light.
Ali Reply
how did you get the value of 2000N.What calculations are needed to arrive at it
Smarajit Reply
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Source:  OpenStax, Object-oriented programming (oop) with java. OpenStax CNX. Jun 29, 2016 Download for free at https://legacy.cnx.org/content/col11441/1.201
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