JAVA Using a variable value as an Instance name

Question

So basically Im reading a file , each line of this file contains description for from 3 to 5 instances of two types of objects with 2 to 4 being first type of object and last one being another type . The file can contain up to 500 lines . I am going to reuse each object from 1 to unknown but on scale of hundrets of times and I need to track their status .

While I can all the data into an array and use only 5 objects changing their values constantly that will make it rather hard to track status of each combination of their parameters .

What I want to is to create my instances with names such as FromLine1Obj1 , FromLine10Obj3 .

I failed to mention the fact that each set of objects from a single line should also create a new thread and this set is proccesed in that thread .

something like Contract Line(linenumber)Obj1 = new Contract(); — user1633277
– user1633277, Commented Aug 29, 2012 at 15:01
where linenumber is the number of line from which object description was taken — user1633277
– user1633277, Commented Aug 29, 2012 at 15:05

Peter Lawrey · Accepted Answer · 2012-08-29 13:38:14Z

4

You need to use a Map.

Map<String, MyObject> map = new ....

map.put("FromLine1Obj1", new MyObject());

MyObject mo = map.get("FromLine1Obj1");

answered Aug 29, 2012 at 13:38

Peter Lawrey

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3 Comments

user1633277 Over a year ago

Thank you for the best answer about Map , but it seems to be just a set of special arrays with additional functions .

Peter Lawrey Over a year ago

HashMap does use an array but TreeMap doesn't. What is your doubt?

user1633277 Over a year ago

I need each line analyzed in a paralell thread . And the number of threads is based on amount of lines in my file .

jdevelop · Accepted Answer · 2012-08-29 13:41:01Z

1

If you read the file once and it will not change after all - you may want to do some code generation, like http://cglib.sourceforge.net/

answered Aug 29, 2012 at 13:41

jdevelop

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4 Comments

user1633277 Over a year ago

The file is basicly a list of insturctions loaded at program start up .

jdevelop Over a year ago

Does it change from compilation to compilation?

user1633277 Over a year ago

Yes the file changes from compilation to compilation , it is also changeable after compilation.

jdevelop Over a year ago

then you will need to use Map, as described in another comments.

Dan · Accepted Answer · 2012-08-29 13:37:52Z

0

Could you not use a map with the name as the key?

answered Aug 29, 2012 at 13:37

Dan

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Comments

jolivier · Accepted Answer · 2012-08-29 13:38:00Z

0

You can store your parsing result in a map, with as key the name you want and as value the created instance, that's the clean way around name indirection in Java.

answered Aug 29, 2012 at 13:38

jolivier

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