// onjava/Countries.java
// (c)2017 MindView LLC: see Copyright.txt
// We make no guarantees that this code is fit for any purpose.
// Visit http://OnJava8.com for more book information.
// "Flyweight" Maps and Lists of sample data
// {java onjava.Countries}
package onjava;
import java.util.*;

public class Countries {
 public static final String[][] DATA = {
 // Africa
 {"ALGERIA","Algiers"},
 {"ANGOLA","Luanda"},
 {"BENIN","Porto-Novo"},
 {"BOTSWANA","Gaberone"},
 {"BURKINA FASO","Ouagadougou"},
 {"BURUNDI","Bujumbura"},
 {"CAMEROON","Yaounde"},
 {"CAPE VERDE","Praia"},
 {"CENTRAL AFRICAN REPUBLIC","Bangui"},
 {"CHAD","N'djamena"},
 {"COMOROS","Moroni"},
 {"CONGO","Brazzaville"},
 {"DJIBOUTI","Dijibouti"},
 {"EGYPT","Cairo"},
 {"EQUATORIAL GUINEA","Malabo"},
 {"ERITREA","Asmara"},
 {"ETHIOPIA","Addis Ababa"},
 {"GABON","Libreville"},
 {"THE GAMBIA","Banjul"},
 {"GHANA","Accra"},
 {"GUINEA","Conakry"},
 {"BISSAU","Bissau"},
 {"COTE D'IVOIR (IVORY COAST)","Yamoussoukro"},
 {"KENYA","Nairobi"},
 {"LESOTHO","Maseru"},
 {"LIBERIA","Monrovia"},
 {"LIBYA","Tripoli"},
 {"MADAGASCAR","Antananarivo"},
 {"MALAWI","Lilongwe"},
 {"MALI","Bamako"},
 {"MAURITANIA","Nouakchott"},
 {"MAURITIUS","Port Louis"},
 {"MOROCCO","Rabat"},
 {"MOZAMBIQUE","Maputo"},
 {"NAMIBIA","Windhoek"},
 {"NIGER","Niamey"},
 {"NIGERIA","Abuja"},
 {"RWANDA","Kigali"},
 {"SAO TOME E PRINCIPE","Sao Tome"},
 {"SENEGAL","Dakar"},
 {"SEYCHELLES","Victoria"},
 {"SIERRA LEONE","Freetown"},
 {"SOMALIA","Mogadishu"},
 {"SOUTH AFRICA","Pretoria/Cape Town"},
 {"SUDAN","Khartoum"},
 {"SWAZILAND","Mbabane"},
 {"TANZANIA","Dodoma"},
 {"TOGO","Lome"},
 {"TUNISIA","Tunis"},
 {"UGANDA","Kampala"},
 {"DEMOCRATIC REPUBLIC OF THE CONGO (ZAIRE)",
 "Kinshasa"},
 {"ZAMBIA","Lusaka"},
 {"ZIMBABWE","Harare"},
 // Asia
 {"AFGHANISTAN","Kabul"},
 {"BAHRAIN","Manama"},
 {"BANGLADESH","Dhaka"},
 {"BHUTAN","Thimphu"},
 {"BRUNEI","Bandar Seri Begawan"},
 {"CAMBODIA","Phnom Penh"},
 {"CHINA","Beijing"},
 {"CYPRUS","Nicosia"},
 {"INDIA","New Delhi"},
 {"INDONESIA","Jakarta"},
 {"IRAN","Tehran"},
 {"IRAQ","Baghdad"},
 {"ISRAEL","Jerusalem"},
 {"JAPAN","Tokyo"},
 {"JORDAN","Amman"},
 {"KUWAIT","Kuwait City"},
 {"LAOS","Vientiane"},
 {"LEBANON","Beirut"},
 {"MALAYSIA","Kuala Lumpur"},
 {"THE MALDIVES","Male"},
 {"MONGOLIA","Ulan Bator"},
 {"MYANMAR (BURMA)","Rangoon"},
 {"NEPAL","Katmandu"},
 {"NORTH KOREA","P'yongyang"},
 {"OMAN","Muscat"},
 {"PAKISTAN","Islamabad"},
 {"PHILIPPINES","Manila"},
 {"QATAR","Doha"},
 {"SAUDI ARABIA","Riyadh"},
 {"SINGAPORE","Singapore"},
 {"SOUTH KOREA","Seoul"},
 {"SRI LANKA","Colombo"},
 {"SYRIA","Damascus"},
 {"TAIWAN (REPUBLIC OF CHINA)","Taipei"},
 {"THAILAND","Bangkok"},
 {"TURKEY","Ankara"},
 {"UNITED ARAB EMIRATES","Abu Dhabi"},
 {"VIETNAM","Hanoi"},
 {"YEMEN","Sana'a"},
 // Australia and Oceania
 {"AUSTRALIA","Canberra"},
 {"FIJI","Suva"},
 {"KIRIBATI","Bairiki"},
 {"MARSHALL ISLANDS","Dalap-Uliga-Darrit"},
 {"MICRONESIA","Palikir"},
 {"NAURU","Yaren"},
 {"NEW ZEALAND","Wellington"},
 {"PALAU","Koror"},
 {"PAPUA NEW GUINEA","Port Moresby"},
 {"SOLOMON ISLANDS","Honaira"},
 {"TONGA","Nuku'alofa"},
 {"TUVALU","Fongafale"},
 {"VANUATU","Port Vila"},
 {"WESTERN SAMOA","Apia"},
 // Eastern Europe and former USSR
 {"ARMENIA","Yerevan"},
 {"AZERBAIJAN","Baku"},
 {"BELARUS (BYELORUSSIA)","Minsk"},
 {"BULGARIA","Sofia"},
 {"GEORGIA","Tbilisi"},
 {"KAZAKSTAN","Almaty"},
 {"KYRGYZSTAN","Alma-Ata"},
 {"MOLDOVA","Chisinau"},
 {"RUSSIA","Moscow"},
 {"TAJIKISTAN","Dushanbe"},
 {"TURKMENISTAN","Ashkabad"},
 {"UKRAINE","Kyiv"},
 {"UZBEKISTAN","Tashkent"},
 // Europe
 {"ALBANIA","Tirana"},
 {"ANDORRA","Andorra la Vella"},
 {"AUSTRIA","Vienna"},
 {"BELGIUM","Brussels"},
 {"BOSNIA-HERZEGOVINA","Sarajevo"},
 {"CROATIA","Zagreb"},
 {"CZECH REPUBLIC","Prague"},
 {"DENMARK","Copenhagen"},
 {"ESTONIA","Tallinn"},
 {"FINLAND","Helsinki"},
 {"FRANCE","Paris"},
 {"GERMANY","Berlin"},
 {"GREECE","Athens"},
 {"HUNGARY","Budapest"},
 {"ICELAND","Reykjavik"},
 {"IRELAND","Dublin"},
 {"ITALY","Rome"},
 {"LATVIA","Riga"},
 {"LIECHTENSTEIN","Vaduz"},
 {"LITHUANIA","Vilnius"},
 {"LUXEMBOURG","Luxembourg"},
 {"MACEDONIA","Skopje"},
 {"MALTA","Valletta"},
 {"MONACO","Monaco"},
 {"MONTENEGRO","Podgorica"},
 {"THE NETHERLANDS","Amsterdam"},
 {"NORWAY","Oslo"},
 {"POLAND","Warsaw"},
 {"PORTUGAL","Lisbon"},
 {"ROMANIA","Bucharest"},
 {"SAN MARINO","San Marino"},
 {"SERBIA","Belgrade"},
 {"SLOVAKIA","Bratislava"},
 {"SLOVENIA","Ljuijana"},
 {"SPAIN","Madrid"},
 {"SWEDEN","Stockholm"},
 {"SWITZERLAND","Berne"},
 {"UNITED KINGDOM","London"},
 {"VATICAN CITY","Vatican City"},
 // North and Central America
 {"ANTIGUA AND BARBUDA","Saint John's"},
 {"BAHAMAS","Nassau"},
 {"BARBADOS","Bridgetown"},
 {"BELIZE","Belmopan"},
 {"CANADA","Ottawa"},
 {"COSTA RICA","San Jose"},
 {"CUBA","Havana"},
 {"DOMINICA","Roseau"},
 {"DOMINICAN REPUBLIC","Santo Domingo"},
 {"EL SALVADOR","San Salvador"},
 {"GRENADA","Saint George's"},
 {"GUATEMALA","Guatemala City"},
 {"HAITI","Port-au-Prince"},
 {"HONDURAS","Tegucigalpa"},
 {"JAMAICA","Kingston"},
 {"MEXICO","Mexico City"},
 {"NICARAGUA","Managua"},
 {"PANAMA","Panama City"},
 {"ST. KITTS AND NEVIS","Basseterre"},
 {"ST. LUCIA","Castries"},
 {"ST. VINCENT AND THE GRENADINES","Kingstown"},
 {"UNITED STATES OF AMERICA","Washington, D.C."},
 // South America
 {"ARGENTINA","Buenos Aires"},
 {"BOLIVIA","Sucre (legal)/La Paz(administrative)"},
 {"BRAZIL","Brasilia"},
 {"CHILE","Santiago"},
 {"COLOMBIA","Bogota"},
 {"ECUADOR","Quito"},
 {"GUYANA","Georgetown"},
 {"PARAGUAY","Asuncion"},
 {"PERU","Lima"},
 {"SURINAME","Paramaribo"},
 {"TRINIDAD AND TOBAGO","Port of Spain"},
 {"URUGUAY","Montevideo"},
 {"VENEZUELA","Caracas"},
 };
 // Use AbstractMap by implementing entrySet()
 private static class FlyweightMap
 extends AbstractMap<String,String> {
 private static class Entry
 implements Map.Entry<String,String> {
 int index;
 Entry(int index) { this.index = index; }
 @Override
 public boolean equals(Object o) {
 return o instanceof FlyweightMap &&
 Objects.equals(DATA[index][0], o);
 }
 @Override
 public int hashCode() {
 return Objects.hashCode(DATA[index][0]);
 }
 @Override
 public String getKey() { return DATA[index][0]; }
 @Override
 public String getValue() {
 return DATA[index][1];
 }
 @Override
 public String setValue(String value) {
 throw new UnsupportedOperationException();
 }
 }
 // Implement size() & iterator() for AbstractSet:
 static class EntrySet
 extends AbstractSet<Map.Entry<String,String>> {
 private int size;
 EntrySet(int size) {
 if(size < 0)
 this.size = 0;
 // Can't be any bigger than the array:
 else if(size > DATA.length)
 this.size = DATA.length;
 else
 this.size = size;
 }
 @Override
 public int size() { return size; }
 private class Iter
 implements Iterator<Map.Entry<String,String>> {
 // Only one Entry object per Iterator:
 private Entry entry = new Entry(-1);
 @Override
 public boolean hasNext() {
 return entry.index < size - 1;
 }
 @Override
 public Map.Entry<String,String> next() {
 entry.index++;
 return entry;
 }
 @Override
 public void remove() {
 throw new UnsupportedOperationException();
 }
 }
 @Override
 public
 Iterator<Map.Entry<String,String>> iterator() {
 return new Iter();
 }
 }
 private static
 Set<Map.Entry<String,String>> entries =
 new EntrySet(DATA.length);
 @Override
 public Set<Map.Entry<String,String>> entrySet() {
 return entries;
 }
 }
 // Create a partial map of 'size' countries:
 static Map<String,String> select(final int size) {
 return new FlyweightMap() {
 @Override
 public Set<Map.Entry<String,String>> entrySet() {
 return new EntrySet(size);
 }
 };
 }
 static Map<String,String> map = new FlyweightMap();
 public static Map<String,String> capitals() {
 return map; // The entire map
 }
 public static Map<String,String> capitals(int size) {
 return select(size); // A partial map
 }
 static List<String> names =
 new ArrayList<>(map.keySet());
 // All the names:
 public static List<String> names() { return names; }
 // A partial list:
 public static List<String> names(int size) {
 return new ArrayList<>(select(size).keySet());
 }
 public static void main(String[] args) {
 System.out.println(capitals(10));
 System.out.println(names(10));
 System.out.println(new HashMap<>(capitals(3)));
 System.out.println(
 new LinkedHashMap<>(capitals(3)));
 System.out.println(new TreeMap<>(capitals(3)));
 System.out.println(new Hashtable<>(capitals(3)));
 System.out.println(new HashSet<>(names(6)));
 System.out.println(new LinkedHashSet<>(names(6)));
 System.out.println(new TreeSet<>(names(6)));
 System.out.println(new ArrayList<>(names(6)));
 System.out.println(new LinkedList<>(names(6)));
 System.out.println(capitals().get("BRAZIL"));
 }
}
/* Output:
{ALGERIA=Algiers, ANGOLA=Luanda, BENIN=Porto-Novo,
BOTSWANA=Gaberone, BURKINA FASO=Ouagadougou,
BURUNDI=Bujumbura, CAMEROON=Yaounde, CAPE VERDE=Praia,
CENTRAL AFRICAN REPUBLIC=Bangui, CHAD=N'djamena}
[ALGERIA, ANGOLA, BENIN, BOTSWANA, BURKINA FASO,
BURUNDI, CAMEROON, CAPE VERDE, CENTRAL AFRICAN
REPUBLIC, CHAD]
{BENIN=Porto-Novo, ANGOLA=Luanda, ALGERIA=Algiers}
{ALGERIA=Algiers, ANGOLA=Luanda, BENIN=Porto-Novo}
{ALGERIA=Algiers, ANGOLA=Luanda, BENIN=Porto-Novo}
{ALGERIA=Algiers, ANGOLA=Luanda, BENIN=Porto-Novo}
[BENIN, BOTSWANA, ANGOLA, BURKINA FASO, ALGERIA,
BURUNDI]
[ALGERIA, ANGOLA, BENIN, BOTSWANA, BURKINA FASO,
BURUNDI]
[ALGERIA, ANGOLA, BENIN, BOTSWANA, BURKINA FASO,
BURUNDI]
[ALGERIA, ANGOLA, BENIN, BOTSWANA, BURKINA FASO,
BURUNDI]
[ALGERIA, ANGOLA, BENIN, BOTSWANA, BURKINA FASO,
BURUNDI]
Brasilia
*/