org.apache.flink.runtime.util

Class KeyGroupedMutableObjectIterator<E>

java.lang.Object

org.apache.flink.runtime.util.KeyGroupedMutableObjectIterator<E>

public final class KeyGroupedMutableObjectIterator<E>
extends Object

The KeyValueIterator returns a key and all values that belong to the key (share the same key). A sub-iterator over all values with the same key is provided.

Constructor Summary

Constructors

Constructor and Description
KeyGroupedMutableObjectIterator(MutableObjectIterator<E> iterator, TypeSerializer<E> serializer, TypeComparator<E> comparator) Initializes the KeyGroupedIterator.

Method Summary

Methods

Modifier and Type	Method and Description
MutableObjectIterator<E>	getValues() Returns an iterator over all values that belong to the current key.
boolean	nextKey() Moves the iterator to the next key.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

KeyGroupedMutableObjectIterator

public KeyGroupedMutableObjectIterator(MutableObjectIterator<E> iterator,
                               TypeSerializer<E> serializer,
                               TypeComparator<E> comparator)

Initializes the KeyGroupedIterator. It requires an iterator which returns its result sorted by the key fields.

Parameters:

iterator - An iterator over records, which are sorted by the key fields, in any order.

serializer - The serializer for the data type iterated over.

comparator - The comparator for the data type iterated over.

Method Detail

nextKey

public boolean nextKey()
                throws IOException

Moves the iterator to the next key. This method may skip any values that have not yet been returned by the iterator created by the getValues() method. Hence, if called multiple times it "removes" pairs.

Returns:

true if the input iterator has an other group of key-value pairs that share the same key.

Throws:

IOException

getValues

public MutableObjectIterator<E> getValues()

Returns an iterator over all values that belong to the current key. The iterator is initially null (before the first call to nextKey() and after all keys are consumed. In general, this method returns always a non-null value, if a previous call to nextKey() return true.

Returns:

Iterator over all values that belong to the current key.