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//: containers/SimpleHashMap.java

package containers; /* Added by Eclipse.py */

// A demonstration hashed Map.

import java.util.*;

import net.mindview.util.*;

public class SimpleHashMap<K,V> extends AbstractMap<K,V> {

// Choose a prime number for the hash table

// size, to achieve a uniform distribution:

static final int SIZE = 997;

// You can't have a physical array of generics,

// but you can upcast to one:

@SuppressWarnings("unchecked")

LinkedList<MapEntry<K,V>>[] buckets =

new LinkedList[SIZE];

public V put(K key, V value) {

V oldValue = null;

int index = Math.abs(key.hashCode()) % SIZE;

if(buckets[index] == null)

buckets[index] = new LinkedList<MapEntry<K,V>>();

LinkedList<MapEntry<K,V>> bucket = buckets[index];

MapEntry<K,V> pair = new MapEntry<K,V>(key, value);

boolean found = false;

ListIterator<MapEntry<K,V>> it = bucket.listIterator();

while(it.hasNext()) {

MapEntry<K,V> iPair = it.next();

if(iPair.getKey().equals(key)) {

oldValue = iPair.getValue();

it.set(pair); // Replace old with new

found = true;

break;

}

}

if(!found)

buckets[index].add(pair);

return oldValue;

}

public V get(Object key) {

int index = Math.abs(key.hashCode()) % SIZE;

if(buckets[index] == null) return null;

for(MapEntry<K,V> iPair : buckets[index])

if(iPair.getKey().equals(key))

return iPair.getValue();

return null;

}

public Set<Map.Entry<K,V>> entrySet() {

Set<Map.Entry<K,V>> set= new HashSet<Map.Entry<K,V>>();

for(LinkedList<MapEntry<K,V>> bucket : buckets) {

if(bucket == null) continue;

for(MapEntry<K,V> mpair : bucket)

set.add(mpair);

}

return set;

}

public static void main(String[] args) {

SimpleHashMap<String,String> m =

new SimpleHashMap<String,String>();

m.putAll(Countries.capitals(25));

System.out.println(m);

System.out.println(m.get("ERITREA"));

System.out.println(m.entrySet());

}

} /* Output:

{CAMEROON=Yaounde, CONGO=Brazzaville, CHAD=N'djamena, COTE D'IVOIR (IVORY COAST)=Yamoussoukro, CENTRAL AFRICAN REPUBLIC=Bangui, GUINEA=Conakry, BOTSWANA=Gaberone, BISSAU=Bissau, EGYPT=Cairo, ANGOLA=Luanda, BURKINA FASO=Ouagadougou, ERITREA=Asmara, THE GAMBIA=Banjul, KENYA=Nairobi, GABON=Libreville, CAPE VERDE=Praia, ALGERIA=Algiers, COMOROS=Moroni, EQUATORIAL GUINEA=Malabo, BURUNDI=Bujumbura, BENIN=Porto-Novo, BULGARIA=Sofia, GHANA=Accra, DJIBOUTI=Dijibouti, ETHIOPIA=Addis Ababa}

Asmara

[CAMEROON=Yaounde, CONGO=Brazzaville, CHAD=N'djamena, COTE D'IVOIR (IVORY COAST)=Yamoussoukro, CENTRAL AFRICAN REPUBLIC=Bangui, GUINEA=Conakry, BOTSWANA=Gaberone, BISSAU=Bissau, EGYPT=Cairo, ANGOLA=Luanda, BURKINA FASO=Ouagadougou, ERITREA=Asmara, THE GAMBIA=Banjul, KENYA=Nairobi, GABON=Libreville, CAPE VERDE=Praia, ALGERIA=Algiers, COMOROS=Moroni, EQUATORIAL GUINEA=Malabo, BURUNDI=Bujumbura, BENIN=Porto-Novo, BULGARIA=Sofia, GHANA=Accra, DJIBOUTI=Dijibouti, ETHIOPIA=Addis Ababa]

*///:~