java - Trying to create an ADT that pairs two objects -

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• does equals method work objects? if so, how? 3 answers

i'm working on abstract data type called pair in java. it's supposed take 2 objects , group them in data type. supposed take less 30 minutes, have been working @ 3 , half hours. believe have first 2 methods right, cannot figure out reverse or equals. can see attempted in code:

public class pair<t1,t2> implements pairinterface<t1,t2> {     // do: instance variables here.     public t1 first;     public t2 second;      public pair(t1 afirst, t2 asecond)     {         first = afirst;         second = asecond;     }      /* gets first element of pair.      * @return first element of pair.      */     public t1 fst()     {         return this.first;     }      /* gets second element of pair.      * @return second element of pair.      */     public t2 snd()     {         return this.second;     }      /* gets new pair represents reversed order      * of pair. example, reverse order of      * pair (x,y) (y,x).      * @return new pair in reverse order      */     public pairinterface<t2,t1> reverse()     {         return pairinterface<this.snd(),this.fst()>;//pair<second;first>     }      /* checks whether 2 pairs equal. note pair      * (a,b) equal pair (x,y) if , if      * equal x , b equal y.      *       * note if forget implement method,      * compiler not complain since class inherits      * method class object.      *       * @param otherobject object compared object.      * @return true if pair equal apair. otherwise      * return false.      */     public boolean equals(object otherobject)     {         if(otherobject == null)         {             return false;         }          if(getclass() != otherobject.getclass())         {             return false;         }          if (otherobject.fst.equals(this.fst) &&             otherobject.snd.equals(this.snd))         {             return true;         } else {             return false;         }     }      /* generates string representing pair. note      * string representing pair (x,y) "(x,y)". there      * no whitespace unless x or y or both contain whitespace      * themselves.      *       * note if forget implement method,      * compiler not complain since class inherits      * method class object.      *       * @return string representing pair.      */     public string tostring()     {         return "("+first.tostring()+","+second.tostring()+")";     } } 

public pairinterface<t2,t1> reverse()     {         return pairinterface<this.snd(),this.fst()>;//pair<second;first>     } 

first of all, can't return this

return pairinterface<this.snd(),this.fst()>;//pair<second;first> 

interfaces define methods class should offer, not implement these methods. therefore, impossible instantiate interface. can returned object implements pairinterface. can follows: return new pair(this.snd(), this.fst());

note instantiate object here keyword new, , give arguments constructor between brackets, instead of placing them between < >.

i don't quite understand yet rest of question about, i'll update post once do. won't give away solution, since, pointed out in comments on post, looks you're trying work.