Re: Updating code from jdk1.2 to recent jdk SE 1.6
On Wednesday, July 11, 2012 12:27:43 AM UTC-7, Sanny wrote:
> > Currently I put data in String.
>
> What do you mean by "data"?
Please attribute your quotes.
Say I have employee data: Name, Tel, City, Salary.
Either I can put them in a class or Comma Separated in single String.
Creating a type is better.
Creating a class then sending that class to a function or database is not much efficient.
It's extremely efficient, as Silvio and I have both pointed out.
But comma separated String you just have to send one string and each Value is separated in the String using "separator comma".
Antipattern.
But addition and removing data from String is very inefficient.
.... [snip] ...
If I use Classes I have to send Employee class to function
No, you don't. You send a *reference* to an *instance* of that class.
1. function changetelnum(EmployeeClass ss, long new_tel, long old_tel)
{
//STEPs LIST
//Search Class with old tel number
You don't search any class (let alone 'Class').
//replace tel number by new_tel
// return(ss);
}
What do you think which one is faster Sending String or Sending a Class? for changing tel number in an Emplyee data?
It's not a question of what anyone thinks, but of what is true.
Is there any other data stricture that does it better?
The data structure that matches the entity you're modeling.
Either you have modeled your domain or you have not.
This is objectively verifiable (i.e., disprovable). Look at the logical
description of any given entity in your model. Does your class definition
match the logical definition? Then it's the right structure, otherwise
not.
When I pass a parameter Class "EmployeeClass" Does the Java Compiler create a new Class ss "EmployeeClass".
No.
As you would know if you read the documentation.
RTFM.
Is there any other way to change telnumber?
The right way.
E.g.,
public class Person
{
private String name;
private String telephone;
public String getName()
{
return name;
}
public void setName(String name)
{
this.name = name;
}
public void setTelephone(String telephone)
{
this.telephone = telephone;
}
public String getTelephone()
{
return telephone;
}
}
Is there something in new versions of Java that can do these things faster?
What was wrong with earlier answers to this very question?
Other thing is How much memory does a class take and a String will take.
That depends.
Say I have an array of 1 million Employees.
String[1million] How many MB this array will take?
That depends.
EmployeeClass[1million] How many MB this array will take?
{
Name:
Tel:
City:
Salary:
}
That's not Java.
Is there a way to save memory for shorter Strings. Say having just 15 digit string? Or all strings are of 256 char size?
'String's are of varying length, and we don't call the characters
in a 'String' "digits".
Read the Java tutorials.
RTFM.
How much Max memory an Applet can take in an ordinary computer.
That depends.
If a Computer has 1 GB RAM can my applet utilize all that RAM? or the Browser will only give a few
No.
MB? Is there any way to request more memory by Applet from web-Browser if Available RAM in Computer is 2GB or 4GB?
No.
How can my Applet know how much Memory is available to the applet?
There are some calls in the API, but it smells like this is the wrong
approach.
Your applet should not care.
How can an Applet know how many cores are present in System and assign each thread to a separate Core?
It cannot.
It should not.
Some of what you're asking you already asked and got answers.
Why are you asking again?
Did you read the earlier answers?
Why not?
--
Lew