Is it possible to create a Map in Java using the concept of pair that exists in C ++? I have tried using the form below, however, I can not assign values to my map.
Map<String, Entry<Entry<Integer,Integer>,String> > sub = new HashMap<>();
How can I resolve this?
Java does not actually have a Pair itself.
You can implement your own class that handles the desired data pair. Usually this class is an implementation of the Map.Entry<K,V> interface. An example implementation can be seen in this answer in the OS:
import java.util.Map;
final class MyEntry<K, V> implements Map.Entry<K, V> {
private final K key;
private V value;
public MyEntry(K key, V value) {
this.key = key;
this.value = value;
}
@Override
public K getKey() {
return key;
}
@Override
public V getValue() {
return value;
}
@Override
public V setValue(V value) {
V old = this.value;
this.value = value;
return old;
}
}
Of course nothing prevents you from creating a class that implements the pair as you wish without implementing this interface.
Or you can use AbstractMap.SimpleEntry<K,V> . It could use like this:
Map<String, Map.Entry<Map.Entry<Integer, Integer>, String>> sub = new HashMap<>();
You would have to create each object of these, go nestling to put on the map:
Map.Entry<Integer, Integer> par1 = new AbstractMap.SimpleEntry<>(0, 1);
Map.Entry<Map.Entry<Integer, Integer>, String> par2 = new AbstractMap.SimpleEntry<>(par1, "txt");
sub.put("chave", par2);