java - ArrayList vs. Array. Why is one working and one isn't? -

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i've been trying switch older assignment on array arraylist, whatever reason find method not working when modify use arraylist.. seems returning -1.

this part of large class don't want include unless necessary, did include declarations in case important:

public class switch {     private switchentry[] camtable;     private int numentries;     private int maxentries;  public switch() {     camtable = new switchentry[100];  // default value     numentries = 0;     maxentries = 100; }  public switch(int maxentries) {     camtable = new switchentry[maxentries];     numentries = 0;     this.maxentries = maxentries; }

original:

public int find (macaddress source) {     int found = -1;     (int i=0; < numentries; i++)         if (source.isequal (camtable[i].getaddress())){             found = i;             break;         }     return found;                }

modified:

public int find (macaddress source) {     int found = -1;     (int i=0; < numentries; i++)         if (source.isequal (camtable.get(i).getaddress())){             found = i;             break;         }     return found;                }

where numentries modified & new entries added arraylist:

public void processframe(frame inframe) {     // first, add source mac camtable if not there     if (find(inframe.getsource()) == -1) {         if (numentries >= maxentries) {             system.out.println ("error...camtable full - cannot add " + inframe.getsource());             } else {              camtable.add(new switchentry(inframe.getsource(), inframe.getport())); //problem line             system.out.println ("adding " + inframe.getsource() + " camtable");         }     }      //process frame     int index = find(inframe.getdestination());     if (index != -1){         system.out.print ("sending frame data " + inframe.getdata() + " " + inframe.getsource() + " " + inframe.getdestination());         system.out.println (" out port " + camtable.get(index).getport() );     } else {         system.out.print ("flooding frame data " + inframe.getdata() + " " + inframe.getsource() + " " + inframe.getdestination());         system.out.println (" out ports"  );      }  }

solution:

camtable.add(numentries++, new switchentry(inframe.getsource(),inframe.getport()));

try this

public int find (macaddress source) {     int found = -1;     arraylist<macaddress> camtable = new arraylist<macaddress>();     listiterator<macaddress> itr = camtable.listiterator();     while(itr.hasnext()){         macaddress tempadd = itr.next();         if(source.getaddress().equals(tempadd.getaddress())){             found = itr.nextindex();             return found;         }         return found;                }

i assume in arraylist store objects of macaddress. in if condition check source.getaddress tempadd.getaddress() same retun index of arraylist. here arraylist local variable can create class variable


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