java - How to make a Person keep a reference to a Player in this code? -

problem: when skeleton enters place, want players screens updated using method in world object:

/**  * `text' in place `place'. text become visible @  * bottom of text window of players watching `place'.  *   * @param place  *            place string displayed.  * @param text  *            string diplayed.  */ public void sayatplace(place place, string text) {     synchronized (players) {         iterator<player> ls = players.iterator();         while (ls.hasnext()) {             player p = ls.next();             if (p.currentplace() == place) {                 p.say(text);             }         }     } } 

i've got 2 classes, person , player , want person write textarea when method goto called can't make person object have proper reference player has textarea:

package adventure;  import java.awt.*; import java.util.*;  /**  * adt persons completed subclasses creating actors  * specific properties  */ public class person {     public player player = null;      /**      * name of person.      */     public string name;      /**      * world person associated with.      */     public world world;      /**      * tells person @ moment.      */     public place where;           /**      * create person named `name' in world `world'.      *       * @param world      *            world person created.      * @param name      *            name of person.      * @param app      *            image used display person.      */     public person(world world, string name, image app) {         this.world = world;         this.name = name;         this.appearance = app;         // this.player = player;         = world.defaultplace();         where.enter(this);          inventory = collections.synchronizedcollection(new linkedlist<thing>());     }      /**      * go directly, , quietly, 'place'. say, without posting      * message you're doing so.      *       * @param place      *            string referring place go to.      * @see #goto(place)      * @see #go      */     public void goto(string place) {         goto(world.getplace(place), null);     }      /**      * go directly, , quietly, `whereto'. say, without posting      * message you're doing so.      *       * @param whereto      *            place go to. can null in case nothing happens.      * @see #goto(string)      * @see #go      */     public void goto(place whereto, player player) {         if (whereto != null) {             where.exit(this);             whereto.enter(this);             // update player's viewing place `where'.             world.update(where);             // record our new position.             = whereto;             // update player's here.             world.update(where);         }          system.out.println("player:"+player);         if(player != null){             player.say("a terrifying skeleton warrior appears!");         }         // send msg doors available         object[] doornames = whereto.exits.keyset().toarray();         string s = "";         int = 1;         (object obj : doornames) {             if (i < doornames.length) {                 s = s + obj.tostring().tolowercase();                  if(i<doornames.length){                      s = s+ ",";                 }              } if (i == doornames.length && > 1) {                 s = s + " , " + obj.tostring().tolowercase();             }             if (i == doornames.length && == 1) {                 s = obj.tostring().tolowercase();             }             ++i;         }         if (player != null) {             player.say("there doors " + s);         }     }    package adventure;  import java.awt.*;  /**  * player object enables commands control person: »you».  * object displayed graphically control panel user both can  * control , follow course of events  */ public class player extends panel {     private person me;     private placeview placeview;     private commands commands;     private textarea textarea;     private static final long serialversionuid = 100l;      /**      * creates new instance of player, in world w, reflecting person p.      *       * @param w      *            world in player play in.      * @param p      *            person associated player.      */     player(world w, person p) {         setlayout(new borderlayout());         setsize(650, 540);          me = p;         p.player = this;         placeview = new placeview(me);         commands = new commands(me);         textarea = new textarea("", 10, 60, textarea.scrollbars_vertical_only);         textarea.append("you in dungeon. horrible shrieks of undead chill bones.\n");         textarea.seteditable(false);         add("west", placeview);         add("east", commands);         add("south", textarea);         w.addplayer(this);     }       /**      * display string in players graphical interface.      *       * @param text      *            string display.      */     void say(string text) {         textarea.append(text + '\n');         textarea.repaint();     }      /**      * returns place of person associated player.      *       * @return place of person associated player.      */     public place currentplace() {         return me.where;     } } 

do understand i'm trying do? code want work is

    system.out.println("player:"+player);     if(player != null && this.name.equals("skeleton")){         player.say("a terrifying skeleton warrior appears!");     } 

but player reference of person zombie not instanciated. person has player object instanciated player person.

can me? posted full versions of person, player , world classes here

http://pastebin.com/rjccr2ph (person) http://pastebin.com/eysh8l9q (player) http://pastebin.com/dkvrvey8 (world)

if understand question well, want have 2 classes in each class has reference other. need create 1 of them (let foo), create other class (let boo) , pass reference of foo via constructor, , set reference of boo inside foo class via setter method.

for example:

public static void main(string[] args) {     foo f = new foo();     boo b = new boo(f);     f.setboo(b); }  class foo {     private boo b;      public foo()     {         // ...     }      public void setboo(boo b)     {         this.b = b;     } }  class boo {     private foo f;      public boo(foo f)     {         this.f = f;     } } 

now, foo has reference of boo, , boo has reference of foo :)