PUT key at a particular location in LinkedHashMap

Thanks a lot for the answers.

Actually my requirement is

I need to maintain a sequence of numbers e.g. 1,2,3,4,5,6,7,8,9

The numbers can be added and removed dynamically

Irrespective of addition and deletion I need to maintain the order

e.g

1) LinkedHashMap has numbers 1,2,3,4,5,6,7,8,9

2) Remove(Start, End) removes the range out. i.e. Remove(3, 6) - LinkedHashMap has 1,2,7,8,9

3) Add(Start, End) add the range i.e. Add(3, 6) - LinkedHashMap will have 1,2,3,4,5,6,7,8,9

4) Unfortunately I am unable to find a data structure that will cater my requirement

Thanks,

Rhea

Rheaa at 2007-7-12 1:58:30 >

> The very very sad part of using TressSet is

>

> if I need elements 1,2,3,4,5,6,7,8,9,10,20

>

> The tree maintains element as

> 1,10,2,20,3,4,5,6,7,8,9

You're mistaken. 1 10 2 20 3 4 5 6 is if you insert Strings into it.

If you inserted Integers into it, then it will be 1 2 3 4 5 6 7 8 10 20

TreeSet<String> x = new TreeSet<String>();

x.add("2");

x.add("10");

x.add("1");

for(String elem:x) { System.out.println(elem); } // This will print 1 10 2

TreeSet<Integer> y = new TreeSet<Integer>();

y.add(2);

y.add(10);

y.add(1);

for(Integer elem:y) { System.out.println(elem); } // This will print 1 2 10

KathyMcDonnella at 2007-7-12 1:58:30 >

> Yes, my numbers are repersented as String. I need them as String.

Just because your INPUT is String, and your OUTPUT is String,

doesn't mean you cannot store them in a TreeSet using its integer value.

Or, unless you are still withholding information.

Are the inputs always numerical? "100", "2", "300"?

Or can the input contain non-numbers also? "abc", "xyz"?

Addendum: even if you insist on storing Strings, you could use a custom comparator for TreeSet

so that it knows how to properly order them. But I don't want to suggest this

since I think you will be better off storing integers rather than Strings.

KathyMcDonnella at 2007-7-12 1:58:30 >

Just because your INPUT is String, and your OUTPUT is String,

doesn't mean you cannot store them in a TreeSet using its integer value.

Addendum: even if you insist on storing Strings, you could use a custom comparator for TreeSet

so that it knows how to properly order them. But I don't want to suggest this

since I think you will be better off storing integers rather than Strings.

KathyMcDonnella at 2007-7-12 1:58:30 >

> Actually Kathy, I string representation is a MUST for me.

You are really, really irritating me.

1) The same data exists at multiple places in your system.

It comes in as characters (bytes in the byte stream, actually).

Then gets parsed into String. And becomes chars again when you System.out.println().

So the data already exists in multiple formats during your program.

For example, if you want to save your data in an Oracle database,

why would you care whether Oracle saves your String as chars/bytes/codepoint/whatever?

Just because your INPUT is String, and your OUTPUT is String,

doesn't mean you cannot store them INTERMEDIATELY as integer.

2) Unless, of course, this is an homework assignment. And that you have

wasted a huge chunk of my time by being vague.

KathyMcDonnella at 2007-7-12 1:58:30 >

Okay, now listen to me very carefully.

1) You CAN store "1", "10", "2" into a TreeSet<String>.

Then write a custom comparator that knows "1" comes before "2" which comes before "10".

http://java.sun.com/j2se/1.5.0/docs/api/java/util/TreeSet.html

http://java.sun.com/j2se/1.5.0/docs/api/java/util/Comparator.html

2) You CAN store 1, 10, 2 into a TreeSet<Integer>.

Then convert String into Integer before adding.

And convert Integer into whatever format you need when you're iterating.

Both choices is doable. Choice 2 is much better because it makes

treeset much faster (int comparison vs String comparison),

it uses far less memory, and you don't need to write a custom comparator.

KathyMcDonnella at 2007-7-21 20:19:35 >