Random value out of a HashMap

Question

Hi, I'm trying to make a translation program (for testing purposes)
I've put the words and their explanation in a HashMap like
key value
Run --- loop(wich is the translation in dutch)
I'm not sure if this is the right collection i need for it.
Another way i know is to create 2 arrays and do it that way...
But now I want to show a random key out of that Map or just loop trough them,how can that be done.
Can a moderator replace my message to the java newbies section :p I didn't saw it until now.
Message was edited by:
stef569
Message was edited by:
stef569
null
Message was edited by:
stef569
Message was edited by:
stef569

Answer 1

I'm in a generous mood
define this interface
import java.util.Map;
public interface RandomMap extends Map {
     Object getRandomValue();
}define this class
import java.util.ArrayList;
import java.util.Collection;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Random;
import java.util.Set;
public class RandomMapImpl implements RandomMap {
     private Map innerMap;
     public RandomMapImpl() {
          innerMap = new HashMap();
     public Object getRandomValue() {
          List list = new ArrayList(innerMap.values());
          if ( list.isEmpty() ) {
               return null;
          int index = new Random(System.currentTimeMillis()).nextInt(list.size() -1);
          return list.get(index);
     public void clear() {
          innerMap.clear();
     public boolean containsKey(Object key) {
          return innerMap.containsKey(key);
     public boolean containsValue(Object value) {
          return innerMap.containsValue(value);
     public Set entrySet() {
          return innerMap.entrySet();
     public Object get(Object key) {
          return innerMap.get(key);
     public boolean isEmpty() {
          return innerMap.isEmpty();
     public Set keySet() {
          return innerMap.keySet();
     public Object put(Object key, Object value) {
          return innerMap.put(key, value);
     public void putAll(Map t) {
          innerMap.putAll(t);
     public Object remove(Object key) {
          return innerMap.remove(key);
     public int size() {
          return innerMap.size();
     public Collection values() {
          return innerMap.values();
}you could make it simpler still by defining the following class instead
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Random;
public class RandomMapImpl extends HashMap implements RandomMap {
     public Object getRandomValue() {
          List list = new ArrayList(values());
          if ( list.isEmpty() ) {
               return null;
          int index = new Random(System.currentTimeMillis()).nextInt(list.size() -1);
          return list.get(index);
}but I'm not a big fan of class inheritance, it could cause you problems later. up to you