gnu.trove.iterator

Interface TIntDoubleIterator

All Superinterfaces:

TAdvancingIterator, TIterator

public interface TIntDoubleIterator
extends TAdvancingIterator

Iterator for maps of type int and double.

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 ( TIntDoubleIterator it = map.iterator(); it.hasNext(); ) {
   it.advance();
   if ( satisfiesCondition( it.key() ) {
     doSomethingWithValue( it.value() );
   }
 }
 

 // modifying values in-place through iteration:
 for ( TIntDoubleIterator it = map.iterator(); it.hasNext(); ) {
   it.advance();
   if ( satisfiesCondition( it.key() ) {
     it.setValue( newValueForKey( it.key() ) );
   }
 }
 

 // deleting entries during iteration:
 for ( TIntDoubleIterator it = map.iterator(); it.hasNext(); ) {
   it.advance();
   if ( satisfiesCondition( it.key() ) {
     it.remove();
   }
 }
 

 // faster iteration by avoiding hasNext():
 TIntDoubleIterator iterator = map.iterator();
 for ( int i = map.size(); i-- > 0; ) {
   iterator.advance();
   doSomethingWithKeyAndValue( iterator.key(), iterator.value() );
 }
 

Method Summary

Modifier and Type	Method and Description
int	key() Provides access to the key of the mapping at the iterator's position.
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.

Methods inherited from interface gnu.trove.iterator.TAdvancingIterator

advance

Methods inherited from interface gnu.trove.iterator.TIterator

hasNext, remove

Method Detail

key

int key()

Provides access to the key of the mapping at the iterator's position. Note that you must advance() the iterator at least once before invoking this method.

Returns:

the key of the entry at the iterator's current position.

value

double value()

Provides access to the value of the mapping at the iterator's position. Note that you must advance() the iterator at least once before invoking this method.

Returns:

the value of the entry at the iterator's current position.

setValue

double setValue(double val)

Replace the value of the mapping at the iterator's position with the specified value. Note that you must advance() the iterator at least once before invoking this method.

Parameters:

val - the value to set in the current entry

Returns:

the old value of the entry.