Package org.apache.solr.client.solrj.io.stream

Class HashJoinStream

java.lang.Object

org.apache.solr.client.solrj.io.stream.TupleStream

org.apache.solr.client.solrj.io.stream.HashJoinStream

All Implemented Interfaces:

Closeable, Serializable, AutoCloseable, Expressible, MapSerializable, MapWriter, NavigableObject

Direct Known Subclasses:

OuterHashJoinStream

public class HashJoinStream
extends TupleStream
implements Expressible

Takes two streams (fullStream and hashStream) and joins them similar to an InnerJoinStream. The difference in a HashJoinStream is that the tuples in the hashStream will all be read and hashed when this stream is opened. This provides a few optimizations iff the hashStream has a relatively small number of documents. You are expected to provide a set of fields for which the hash will be calculated from. If a tuple does not contain a value (ie, null) for one of the fields the hash is being computed on then that tuple will not be considered a match to anything. Ie, all fields which are part of the hash must have a non-null value.

Since:

6.0.0

See Also:

Serialized Form

Nested Class Summary

Nested classes/interfaces inherited from class org.apache.solr.client.solrj.io.stream.TupleStream

TupleStream.IgnoreException

Nested classes/interfaces inherited from interface org.apache.solr.common.MapWriter

MapWriter.EntryWriter

Field Summary

Fields

Modifier and Type	Field	Description
protected TupleStream	fullStream
protected HashMap<String,List<Tuple>>	hashedTuples
protected TupleStream	hashStream
protected List<String>	leftHashOn
protected List<String>	rightHashOn
protected String	workingFullHash
protected Tuple	workingFullTuple
protected int	workngHashSetIdx

Constructor Summary

Constructors

Constructor	Description
HashJoinStream(StreamExpression expression, StreamFactory factory)
HashJoinStream(TupleStream fullStream, TupleStream hashStream, List<String> hashOn)

Method Summary

Modifier and Type	Method	Description
List<TupleStream>	children()
void	close()
protected String	computeHash(Tuple tuple, List<String> hashOn)
int	getCost()
StreamComparator	getStreamSort()
void	open()
Tuple	read()
void	setStreamContext(StreamContext context)
Explanation	toExplanation(StreamFactory factory)	Returns an explanation about the stream object
StreamExpression	toExpression(StreamFactory factory)

Methods inherited from class org.apache.solr.client.solrj.io.stream.TupleStream

getShards, getStreamNodeId, writeMap

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.apache.solr.common.MapWriter

jsonStr, toMap

Methods inherited from interface org.apache.solr.common.NavigableObject

_forEachEntry, _forEachEntry, _forEachEntry, _get, _get, _getStr, _getStr

Field Detail

hashStream

protected TupleStream hashStream

fullStream

protected TupleStream fullStream

leftHashOn

protected List<String> leftHashOn

rightHashOn

protected List<String> rightHashOn

hashedTuples

protected HashMap<String,List<Tuple>> hashedTuples

workingFullTuple

protected Tuple workingFullTuple

workingFullHash

protected String workingFullHash

workngHashSetIdx

protected int workngHashSetIdx

Constructor Detail

HashJoinStream

public HashJoinStream(TupleStream fullStream,
                      TupleStream hashStream,
                      List<String> hashOn)
               throws IOException

Throws:

IOException

HashJoinStream

public HashJoinStream(StreamExpression expression,
                      StreamFactory factory)
               throws IOException

Throws:

IOException

Method Detail

toExpression

public StreamExpression toExpression(StreamFactory factory)
                              throws IOException

Specified by:

toExpression in interface Expressible

Throws:

IOException

toExplanation

public Explanation toExplanation(StreamFactory factory)
                          throws IOException

Description copied from interface: Expressible

Returns an explanation about the stream object

Specified by:

toExplanation in interface Expressible

Specified by:

toExplanation in class TupleStream

Parameters:

factory - Stream factory for this, contains information about the function name

Returns:

Explanation about this stream object containing explanations of any child stream objects

Throws:

IOException - throw on any error

setStreamContext

public void setStreamContext(StreamContext context)

Specified by:

setStreamContext in class TupleStream

children

public List<TupleStream> children()

Specified by:

children in class TupleStream

open

public void open()
          throws IOException

Specified by:

open in class TupleStream

Throws:

IOException

computeHash

protected String computeHash(Tuple tuple,
                             List<String> hashOn)

close

public void close()
           throws IOException

Specified by:

close in interface AutoCloseable

Specified by:

close in interface Closeable

Specified by:

close in class TupleStream

Throws:

IOException

read

public Tuple read()
           throws IOException

Specified by:

read in class TupleStream

Throws:

IOException

getStreamSort

public StreamComparator getStreamSort()

Specified by:

getStreamSort in class TupleStream

getCost

public int getCost()

Overrides:

getCost in class TupleStream