K - the type of the keys in the map
V - the type of the values in the map
public interface MapIterator<K,V> extends Iterator<K>
Map.
This iterator is a special version designed for maps. It can be more efficient to use this rather than an entry set iterator where the option is available, and it is certainly more convenient.
A map that provides this interface may not hold the data internally using Map Entry objects, thus this interface can avoid lots of object creation.
In use, this iterator iterates through the keys in the map. After each call to next(), the getValue() method provides direct access to the value. The value can also be set using setValue().
MapIterator
it = map.mapIterator();
while (it.hasNext()) {
String key = it.next();
Integer value = it.getValue();
it.setValue(value + 1);
}
| Modifier and Type | Method and Description |
|---|---|
K |
getKey()
Gets the current key, which is the key returned by the last call to
next().
|
V |
getValue()
Gets the current value, which is the value associated with the last key returned by
next().
|
boolean |
hasNext()
Checks to see if there are more entries still to be iterated.
|
K |
next()
Gets the next
key from the
Map.
|
void |
remove()
Removes the last returned key from the underlying
Map (optional operation).
|
V |
setValue(V value)
Sets the value associated with the current key (optional operation).
|
forEachRemainingboolean hasNext()
K next()
Map.
next in interface
Iterator<K>
NoSuchElementException - if the iteration is finished
K getKey()
next().
IllegalStateException - if
next() has not yet been called
V getValue()
next().
IllegalStateException - if
next() has not yet been called
void remove()
Map (optional operation).
This method can be called once per call to next().
remove in interface
Iterator<K>
UnsupportedOperationException - if remove is not supported by the map
IllegalStateException - if
next() has not yet been called
IllegalStateException - if
remove() has already been called since the last call to
next()
V setValue(V value)
value - the new value
UnsupportedOperationException - if setValue is not supported by the map
IllegalStateException - if
next() has not yet been called
IllegalStateException - if
remove() has been called since the last call to
next()