java - ItemRegister Iterator -

i trying create item register register items inside rooms.

in room class have

  /**      * gets item description      */     public arraylist<item> getitem()     {       return items;     } 

and in item register have

public class itemregister {     private hashmap<string,item> items;     /**      * constructor objects of class itemregister      */     public itemregister()     {         items = new hashmap<string,item>();      }     /**      * register items in hashmap      */     public void register(item a)     {         items.put(a.getdescription(),a);       }       public void register(arraylist<item> a)     {        iterator<item> = a.iterator();        while (i.hasnext())        {         room room = i.next();          if (room.getitem() != null && room.getitem().equals(a))         {          }         else{          }        }      } } 

i trying complete iterator cycle through room , if finds item inside room register placing hashmap

hopefully enough going:

import java.util.*;  public class itemregister{      public static void main(string []args){         itemregister ir = new itemregister();     }      // storing items registered here     private hashmap<string,item> items;      /**      * constructor objects of class itemregister      */     public itemregister(){         items = new hashmap<string,item>();          arraylist<room> roomlist = new arraylist<>();         roomlist.add( new room( new item("item a") ) );         roomlist.add( new room( new item("item b") ) );         roomlist.add( new room( new item("item c") ) );         roomlist.add( new room( new item("item d") ) );           system.out.println( "size of registered items:" + items.size() );           // register item         item aitem = new item("item a");         register( roomlist, aitem );          /// print whatever in register         system.out.println( "size of registered items:" + items.size() );          system.out.println( "registered items:" );           for( item item : items.values() ){             system.out.println( item.getdescription() );          }         system.out.println( "---- end ----" );           // register b item         item bitem = new item("item b");                 register( roomlist, bitem );          /// print whatever in register         system.out.println( "size of registered items:" + items.size() );          system.out.println( "registered items:" );           for( item item : items.values() ){             system.out.println( item.getdescription() );          }         system.out.println( "---- end ----" );      }      /**      * register items in hashmap      */     public void register(item a){         items.put(a.getdescription(), a);         system.out.println( "registered item" );      }      public void register(arraylist<room> roomlist, item a){         iterator = roomlist.iterator();          while (i.hasnext()) {             room room = (room)i.next();              if (room.getitem() != null && room.getitem().equals(a)){                 register( room.getitem() );             }         }     }      /* class item */     protected class item{         private string description;          item(string description){             this.description = description;         }          public string getdescription(){             return this.description;         }          public boolean equals(object o) {         if (this == o) {             return true;         }         if (!(o instanceof item)) {             return false;         }          item item = (item) o;          if (!description.equals(item.description)) {             return false;         }          return true;     }     }      /* class room */     protected class room{         private item item;          room( item item ){             this.item = item;         }          public item getitem(){             return this.item;         }     } }