57 lines
1.8 KiB
Java
57 lines
1.8 KiB
Java
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//: containersindepth/SlowMap.java
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// <20>2015 MindView LLC: see Copyright.txt
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// A Map implemented with ArrayLists.
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import java.util.*;
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import com.mindviewinc.util.*;
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public class SlowMap<K,V> extends AbstractMap<K,V> {
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private List<K> keys = new ArrayList<>();
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private List<V> values = new ArrayList<>();
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@Override
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public V put(K key, V value) {
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V oldValue = get(key); // The old value or null
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if(!keys.contains(key)) {
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keys.add(key);
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values.add(value);
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} else
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values.set(keys.indexOf(key), value);
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return oldValue;
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}
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@Override
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public V get(Object key) { // key is type Object, not K
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if(!keys.contains(key))
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return null;
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return values.get(keys.indexOf(key));
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}
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@Override
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public Set<Map.Entry<K,V>> entrySet() {
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Set<Map.Entry<K,V>> set= new HashSet<>();
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Iterator<K> ki = keys.iterator();
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Iterator<V> vi = values.iterator();
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while(ki.hasNext())
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set.add(new MapEntry<>(ki.next(), vi.next()));
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return set;
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}
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public static void main(String[] args) {
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SlowMap<String,String> m= new SlowMap<>();
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m.putAll(Countries.capitals(15));
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System.out.println(m);
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System.out.println(m.get("BULGARIA"));
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System.out.println(m.entrySet());
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}
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} /* Output:
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{ANGOLA=Luanda, CAPE VERDE=Praia, EGYPT=Cairo,
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BURUNDI=Bujumbura, BENIN=Porto-Novo, ALGERIA=Algiers,
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CAMEROON=Yaounde, CONGO=Brazzaville, CENTRAL AFRICAN
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REPUBLIC=Bangui, EQUATORIAL GUINEA=Malabo, COMOROS=Moroni,
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DJIBOUTI=Dijibouti, BURKINA FASO=Ouagadougou,
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CHAD=N'djamena, BOTSWANA=Gaberone}
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null
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[ANGOLA=Luanda, CAPE VERDE=Praia, EGYPT=Cairo,
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BURUNDI=Bujumbura, BENIN=Porto-Novo, ALGERIA=Algiers,
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CAMEROON=Yaounde, CONGO=Brazzaville, CENTRAL AFRICAN
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REPUBLIC=Bangui, EQUATORIAL GUINEA=Malabo, COMOROS=Moroni,
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DJIBOUTI=Dijibouti, BURKINA FASO=Ouagadougou,
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CHAD=N'djamena, BOTSWANA=Gaberone]
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*///:~
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