JAVA SORT COLLECTION List or Vector or arraylist or array

http://docs.oracle.com/javase/tutorial/collections/interfaces/order.html


Sort vector or List

import java.util.*; 

public class Test

{

class BedFormat implements Comparable 

  {
    String chrom;
    int end;
    public int compareTo(BedFormat obj) {
       
        return (this.end > obj.end ) ? 1  :  -1 ;
    } 

   }  

public static void main()

{ 

     List vp = new ArrayList();

     vp.add(new BedFormat());

     vp.add(new BedFormat());

      .... 

     vp.add(new BedFormat()); 

     Collections.sort( vp  );

     // print 

     // it will print according to end variable of object

}

}

Example : Finding Median from a list

class ExpReplica implements Comparable{

     
     double valReplica;
     
     
     public ExpReplica(double valReplica) {
   super();
   this.valReplica = valReplica;
  }


  public int compareTo(ExpReplica obj) {
        
         return (this.valReplica > obj.valReplica ) ? 1  :  -1 ;
     }


  public double getValReplica() {
   return valReplica;
  }


  public void setValReplica(double valReplica) {
   this.valReplica = valReplica;
  } 
  
 }  

 void FindMedianFromArray()
 {
  
     Double tmp[] = { 6.7 , 2.3 , 8.9, 11.1 , 91.5 };
   
   double finalValue=0.0;
   int listSize;
     
   List myArrayList = new ArrayList();
   for(int c=0; c   {
    myArrayList.add(new ExpReplica( tmp[c] ) );
   }

   Collections.sort( myArrayList  );
    
   listSize=myArrayList.size();
    
   if(listSize==1)
   {
    finalValue = ( (ExpReplica)myArrayList.get(0) ).getValReplica() ;
    
   }else if(listSize%2 ==0) // even - select the big one
   {
    finalValue =  ( (ExpReplica)myArrayList.get(listSize/2) ).getValReplica() ;
   }else // odd - take the middle one
   {
    finalValue =  ( (ExpReplica)myArrayList.get(listSize/2) ).getValReplica() ;
   }
    
   System.out.println( "Median:" + "\t"+ finalValue); 
  
 }