com.bigdata.striterator

Class ChunkedFilter<I extends IChunkedIterator<E>,E,F>

java.lang.Object

com.bigdata.striterator.ChunkedFilter<I,E,F>

Type Parameters:

I - The parameterized generic type of the source iterator.

E - The generic type of the elements visited by the source iterator.

F - The generic type of the elements after applying this filter. This will differ from E iff the filter is transforming the element type.

All Implemented Interfaces:

IFilter<I,E,F>, Serializable

public abstract class ChunkedFilter<I extends IChunkedIterator<E>,E,F>
extends Object
implements IFilter<I,E,F>

Chunk-at-a-time filter.

Version:

$Id$

Author:

Bryan Thompson

See Also:

Serialized Form

Field Summary

Fields

Modifier and Type	Field and Description
protected IKeyOrder<F>	keyOrder The natural order of the filtered chunks.
protected Object	state Caller's object.

Constructor Summary

Constructors

Constructor and Description
ChunkedFilter()
ChunkedFilter(Object state)
ChunkedFilter(Object state, IKeyOrder<F> keyOrder)

Method Summary

Methods

Modifier and Type	Method and Description
IChunkedOrderedIterator<F>	filter(I src) Wrap the source iterator with an iterator that applies this filter.
protected abstract F[]	filterChunk(E[] chunk) Process a chunk of elements, returning another chunk of elements.

Methods inherited from class java.lang.Object

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

Field Detail

state

protected Object state

Caller's object.

keyOrder

protected final IKeyOrder<F> keyOrder

The natural order of the filtered chunks. This field is set iff specified explicitly to the ctor and is otherwise null. When null the filtered iterator is assumed to be unordered. This assumption is made since chunk-at-a-time transforms can change the natural order of the chunk in many, many different ways, e.g., by changing the type of the elements in the chunk.

Constructor Detail

ChunkedFilter

public ChunkedFilter()

ChunkedFilter

public ChunkedFilter(Object state)

ChunkedFilter

public ChunkedFilter(Object state,
             IKeyOrder<F> keyOrder)

Parameters:

state - Application state (optional).

keyOrder - The natural sort order for the filtered iterator (optional).

Method Detail

filter

public IChunkedOrderedIterator<F> filter(I src)

Wrap the source iterator with an iterator that applies this filter.

Note: There was a historical compiler problem with this method when generics were not specified.

Specified by:

filter in interface IFilter<I extends IChunkedIterator<E>,E,F>

Parameters:

src - The source iterator.

Returns:

The filtered iterator.

See Also:

Java 7 Compatibility

filterChunk

protected abstract F[] filterChunk(E[] chunk)

Process a chunk of elements, returning another chunk of elements.

Parameters:

chunk - A chunk of elements from the source iterator.

Returns:

The next chunk of elements to be visited by the filtered iterator. If all elements are filtered then this method should return either an empty chunk or null.