Sort an ArrayList based on an object field

Java

Java Problem Overview

> Possible Duplicate:
> Sorting an ArrayList of Contacts

I am storing DataNode objects in an ArrayList. The DataNode class has an integer field called degree. I want to retrieve DataNode objects from nodeList in the increasing order of degree. How can I do it.

List<DataNode> nodeList = new ArrayList<DataNode>();

Java Solutions

Solution 1 - Java

Use a custom comparator:

Collections.sort(nodeList, new Comparator<DataNode>(){
     public int compare(DataNode o1, DataNode o2){
         if(o1.degree == o2.degree)
             return 0;
         return o1.degree < o2.degree ? -1 : 1;
     }
});

Solution 2 - Java

Modify the DataNode class so that it implements Comparable interface.

public int compareTo(DataNode o)
{
     return(degree - o.degree);
}

then just use

Collections.sort(nodeList);

Solution 3 - Java

You can use the Bean Comparator to sort on any property in your custom class.

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Content TypeOriginal AuthorOriginal Content on Stackoverflow
QuestionsoftwarematterView Question on Stackoverflow
Solution 1 - JavaMark ElliotView Answer on Stackoverflow
Solution 2 - JavablitzkriegzView Answer on Stackoverflow
Solution 3 - JavacamickrView Answer on Stackoverflow