collections - Implementing COMPARATOR in java -

i new java , in implementing comparator. have arraylist of type qualitydata following values.

**sequence nr**  **súb sequence_nr** **flag**         100             1              true         100             1              false         101             1              true         100             2              false         100             1              false         100             3              true 

desired output order: orderíng based on sequence_nr , sub_sequence_nr.

  **sequence nr**  **súb sequence_nr**  **flag**          100              1               true          100              1               false          100              1               false          100              2               false          100              3               true          101              1               true 

i have class sequence_number, sub_sequence_number , boolean flag.

public class qualitydata{ private int sequence_number; private int sub_sequence_nr; private boolean flag;  //getter, setter methods public static comparator<qualitydata> comparator=new comparator<qualitydata>(){     public int compare(qualitydata data1, qualitydata data2){         return int (data1.getsequence_nr()-data2.getsequence_nr());     } }; } 

and sort calling:

list<qualitydata> qdata= ie.getqualitydata(); collections.sort(qdata,qualitydata.comparator); 

here, have implemented comparator based on sequence_number want based on sequence_number , sub_sequence_nr. please me?

i not posting working solution here, give complete idea need , how solve it

       public static comparator<qualitydata> comparator=new comparator<qualitydata>(){             public int compare(qualitydata data1, qualitydata data2){                 if((data1.getsequence_nr()-data2.getsequence_nr() == 0)){                     if(data1.getsubsequence_nr()-data2.getsubsequence_nr() == 0){                         if(data1.getflag()){                            return 1;                             }else{                             return -1;                         }                     }else{                         return data1.getsubsequence_nr()-data2.getsubsequence_nr();                     }                 }else {                     return data1.getsequence_nr()-data2.getsequence_nr();                 }             }         };         }