public class TFloatDoubleIterator
extends java.lang.Object
The iterator semantics for Trove's primitive maps is slightly different from those defined in java.util.Iterator, but still well within the scope of the pattern, as defined by Gamma, et al.
This iterator does not implicitly advance to the next entry when the value at the current position is retrieved. Rather, you must explicitly ask the iterator to advance() and then retrieve either the key(), the value() or both. This is done so that you have the option, but not the obligation, to retrieve keys and/or values as your application requires, and without introducing wrapper objects that would carry both. As the iteration is stateful, access to the key/value parts of the current map entry happens in constant time.
In practice, the iterator is akin to a "search finger" that you move from position to position. Read or write operations affect the current entry only and do not assume responsibility for moving the finger.
Here are some sample scenarios for this class of iterator:
// accessing keys/values through an iterator: for (TFloatDoubleIterator it = map.iterator(); it.hasNext();) { it.advance(); if (satisfiesCondition(it.key()) { doSomethingWithValue(it.value()); } }
// modifying values in-place through iteration: for (TFloatDoubleIterator it = map.iterator(); it.hasNext();) { it.advance(); if (satisfiesCondition(it.key()) { it.setValue(newValueForKey(it.key())); } }
// deleting entries during iteration: for (TFloatDoubleIterator it = map.iterator(); it.hasNext();) { it.advance(); if (satisfiesCondition(it.key()) { it.remove(); } }
// faster iteration by avoiding hasNext(): TFloatDoubleIterator iterator = map.iterator(); for (int i = map.size(); i-- > 0;) { iterator.advance(); doSomethingWithKeyAndValue(iterator.key(), iterator.value()); }
Modifier and Type | Field | Description |
---|---|---|
protected int |
_expectedSize |
the number of elements this iterator believes are in the
data structure it accesses.
|
protected TPrimitiveHash |
_hash |
the collection on which this iterator operates.
|
protected int |
_index |
the index used for iteration.
|
Constructor | Description |
---|---|
TFloatDoubleIterator(TFloatDoubleHashMap map) |
Creates an iterator over the specified map
|
Modifier and Type | Method | Description |
---|---|---|
void |
advance() |
Moves the iterator forward to the next entry in the underlying map.
|
boolean |
hasNext() |
Returns true if the iterator can be advanced past its current
location.
|
float |
key() |
Provides access to the key of the mapping at the iterator's position.
|
protected void |
moveToNextIndex() |
Sets the internal index so that the `next' object
can be returned.
|
protected int |
nextIndex() |
Returns the index of the next value in the data structure
or a negative value if the iterator is exhausted.
|
void |
remove() |
Removes the last entry returned by the iterator.
|
double |
setValue(double val) |
Replace the value of the mapping at the iterator's position with the
specified value.
|
double |
value() |
Provides access to the value of the mapping at the iterator's position.
|
protected final TPrimitiveHash _hash
protected int _expectedSize
protected int _index
public TFloatDoubleIterator(TFloatDoubleHashMap map)
public void advance()
java.util.NoSuchElementException
- if the iterator is already exhaustedpublic float key()
public double value()
public double setValue(double val)
val
- the value to set in the current entryprotected final int nextIndex()
int
valuejava.util.ConcurrentModificationException
- if the underlying collection's
size has been modified since the iterator was created.public boolean hasNext()
boolean
valuepublic void remove()
protected final void moveToNextIndex()
GNU Trove is copyright ? 2001-2009 Eric D. Friedman. All Rights Reserved.