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java.lang.Objectgnu.trove.TIterator
gnu.trove.TObjectDoubleIterator
public class TObjectDoubleIterator
Iterator for maps of type Object 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 (TObjectDoubleIterator it = map.iterator(); it.hasNext();) { it.forward(); if (satisfiesCondition(it.key()) { doSomethingWithValue(it.value()); } }
// modifying values in-place through iteration: for (TObjectDoubleIterator it = map.iterator(); it.hasNext();) { it.forward(); if (satisfiesCondition(it.key()) { it.setValue(newValueForKey(it.key())); } }
// deleting entries during iteration: for (TObjectDoubleIterator it = map.iterator(); it.hasNext();) { it.forward(); if (satisfiesCondition(it.key()) { it.remove(); } }
// faster iteration by avoiding hasNext(): TObjectDoubleIterator iterator = map.iterator(); for (int i = map.size(); i-- > 0;) { iterator.advance(); doSomethingWithKeyAndValue(iterator.key(), iterator.value()); }
Field Summary | |
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private TObjectDoubleHashMap |
_map
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Fields inherited from class gnu.trove.TIterator |
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_expectedSize, _hash, _index |
Constructor Summary | |
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TObjectDoubleIterator(TObjectDoubleHashMap map)
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Method Summary | |
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void |
advance()
Moves the iterator forward to the next entry in the underlying map. |
java.lang.Object |
key()
Provides access to the key of the mapping at the iterator's position. |
protected int |
nextIndex()
Returns the index of the next value in the data structure or a negative value if the iterator is exhausted. |
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 class gnu.trove.TIterator |
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hasNext, moveToNextIndex, remove |
Methods inherited from class java.lang.Object |
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clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
Field Detail |
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private final TObjectDoubleHashMap _map
Constructor Detail |
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public TObjectDoubleIterator(TObjectDoubleHashMap map)
Method Detail |
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protected final int nextIndex()
nextIndex
in class TIterator
int
valuepublic void advance()
NoSuchElementException
- if the iterator is already exhaustedpublic java.lang.Object key()
public double value()
public double setValue(double val)
val
- the value to set in the current entry
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