Re: CIAO, How can I sort an ArrayList<K> of Generic Types ?

On Wed, 21 May 2008 06:38:06 -0700, Giordano wrote:

"Ciao" (Hi) to everyone,
please can you tell me how can I sort an ArrayList<K> of generic types ?

If this arraylist were of this kind, ArrayList<String>, I could sort it
simply using this instruction:

ArrayList<String> list = new ArrayList<String>();
java.util.Collections.sort ( list );

but, in my case, i see that i cannot sort in this same way when i use an
arraylist of generic types.. like this one:

ArrayList<K> list = new ArrayList<K>(); /* ERROR --> */
java.util.Collections.sort ( list );


/* ERROR --> */ javac myProva.java
.\myIndexedTreeMap.java:46: cannot find symbol symbol : method
sort(java.util.ArrayList<K>) location: class java.util.Collections
Collections.sort (list);
^
1 error

Thanks if you can give me any help for my question ? Ciao

Hi,

Collections.sort is expecting a List containing objects implementing the
Comparable interface.

Did your K class implements Comparable ?

Hope this helps,

Vivien Barousse
.

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