MapIterator (Apache Commons Collections 3.2.2 API)

All Superinterfaces:

Iterator

All Known Subinterfaces:

OrderedMapIterator

All Known Implementing Classes:

AbstractDualBidiMap.BidiMapIterator, AbstractHashedMap.HashMapIterator, AbstractLinkedMap.LinkMapIterator, AbstractMapIteratorDecorator, AbstractOrderedMapIteratorDecorator, DualTreeBidiMap.BidiOrderedMapIterator, EmptyMapIterator, EmptyOrderedMapIterator, EntrySetMapIterator, UnmodifiableMapIterator, UnmodifiableOrderedMapIterator
```
public interface MapIterator
extends Iterator
```
Defines an iterator that operates over a 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()) {
   Object key = it.next();
   Object value = it.getValue();
   it.setValue(newValue);
 }
 
```
Since:

Commons Collections 3.0

Version:

$Revision: 972404 $ $Date: 2008-04-10 14:33:15 +0200 (Thu, 10 Apr 2008) $

Author:

Stephen Colebourne

Method Summary

Methods
Modifier and Type	Method and Description
`Object`	`getKey()` Gets the current key, which is the key returned by the last call to `next()`.
`Object`	`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.
`Object`	`next()` Gets the next key from the `Map`.
`void`	`remove()` Removes the last returned key from the underlying `Map` (optional operation).
`Object`	`setValue(Object value)` Sets the value associated with the current key (optional operation).

- Method Detail
  - hasNext
```
boolean hasNext()
```
    Checks to see if there are more entries still to be iterated.
    
    Specified by:
    
    hasNext in interface Iterator
    
    Returns:
    true if the iterator has more elements
  - next
```
Object next()
```
    Gets the next key from the Map.
    
    Specified by:
    
    next in interface Iterator
    
    Returns:
    the next key in the iteration
    
    Throws:
    
    NoSuchElementException - if the iteration is finished
  - getKey
```
Object getKey()
```
    Gets the current key, which is the key returned by the last call to next().
    
    Returns:
    the current key
    
    Throws:
    
    IllegalStateException - if next() has not yet been called
  - getValue
```
Object getValue()
```
    Gets the current value, which is the value associated with the last key returned by next().
    
    Returns:
    the current value
    
    Throws:
    
    IllegalStateException - if next() has not yet been called
  - remove
```
void remove()
```
    Removes the last returned key from the underlying Map (optional operation).
    This method can be called once per call to next().
    
    Specified by:
    
    remove in interface Iterator
    
    Throws:
    
    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()
  - setValue
```
Object setValue(Object value)
```
    Sets the value associated with the current key (optional operation).
    
    Parameters:
    value - the new value
    
    Returns:
    the previous value
    
    Throws:
    
    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()

Interface MapIterator

Method Summary

Method Detail

hasNext

next

getKey

getValue

remove

setValue