com.davisor.data.stream
Class TupleDataStream

java.lang.Object
  com.davisor.data.VoidData
      com.davisor.data.stream.TupleDataStream

All Implemented Interfaces:

Data, DataStream

public class TupleDataStream

extends VoidData

implements DataStream

A TupleDataStream allows tuple elements in a tuple data stream to be rearranged at will, or to make ordinary data streams tuple streams.

Since:

JDK1.1

See Also:

TupleData, TupleType

Field Summary

protected TupleData	M_data Next element, if any.
protected long	M_index Element id counter.
protected int[]	M_map Tuple element reorder indexes.
protected java.lang.Object	M_metaData Stream meta data (may be null).
protected DataStream	M_stream Source stream.
protected boolean	M_tuplify Tuple element arrangement method indicator.

Fields inherited from class com.davisor.data.VoidData

M_type

Fields inherited from interface com.davisor.data.stream.DataStream

INITIAL_INDEX

Constructor Summary

TupleDataStream(DataStream stream)
Creates a tuple data stream from any data stream.

TupleDataStream(DataStream stream, TupleType type)
Creates a tuple data stream from any data stream.

TupleDataStream(DataStream stream, TupleType type, int[] map)
Creates a tuple data stream from any data stream.

Method Summary

boolean	close() This method frees resources for cargabe collection.
long	getIndex() Retrieves the index number of the element returned by the latest next() call.
boolean	hasNext() Tests if the stream still contains data.
DataValue	next() Gets the next data from the stream.

Methods inherited from class com.davisor.data.VoidData

equals, getDataValue, getType, hashCode, setType, toString

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Methods inherited from interface com.davisor.data.Data

getType

Field Detail

M_data

protected TupleData M_data

Next element, if any.

M_index

protected long M_index

Element id counter.

M_map

protected int[] M_map

Tuple element reorder indexes.

M_metaData

protected java.lang.Object M_metaData

Stream meta data (may be null).

M_stream

protected DataStream M_stream

Source stream.

M_tuplify

protected boolean M_tuplify

Tuple element arrangement method indicator.

Constructor Detail

TupleDataStream

public TupleDataStream(DataStream stream)
                throws InvalidDataException

Creates a tuple data stream from any data stream. If the given data stream contains tuples, it is accepted unchanged. If the given stream does not contain tuples, then the stream elements will be arranged into one element tuples.

Parameters:

stream - source stream

Throws:

InvalidDataException - if the collection content does not satisfy the given type.

See Also:

TupleType.getTypeIndex(java.lang.String), TupleType.getTypeIndexMap(com.davisor.data.TupleType), TupleType.rearrange(com.davisor.data.TupleData, int[])

TupleDataStream

public TupleDataStream(DataStream stream,
                       TupleType type)
                throws InvalidDataException

Creates a tuple data stream from any data stream. If the given data stream contains tuples, their content will be rearranged as specified by the given tuple type. If the given stream does not contain tuples, then the stream elements will be arranged into a tuple of the given type.

Parameters:

stream - source stream

type - new type

Throws:

InvalidDataException - if the collection content does not satisfy the given type.

See Also:

TupleType.getTypeIndex(java.lang.String), TupleType.getTypeIndexMap(com.davisor.data.TupleType), TupleType.rearrange(com.davisor.data.TupleData, int[])

TupleDataStream

public TupleDataStream(DataStream stream,
                       TupleType type,
                       int[] map)
                throws InvalidDataException

Creates a tuple data stream from any data stream. If the given data stream contains tuples, their content will be rearranged as specified by the given tuple type. If the given stream does not contain tuples, then the stream elements will be arranged into a tuple of the given type.

Parameters:

stream - source stream

type - new type

map - precomputed tuple member index map

Throws:

InvalidDataException - if the collection content does not satisfy given type.

See Also:

TupleType.getTypeIndex(java.lang.String), TupleType.getTypeIndexMap(com.davisor.data.TupleType), TupleType.rearrange(com.davisor.data.TupleData, int[])

Method Detail

close

public boolean close()

This method frees resources for cargabe collection.

Specified by:

close in interface DataStream

Returns:

true

See Also:

DataStream.hasNext()

getIndex

public long getIndex()

Retrieves the index number of the element returned by the latest next() call. The index represents the position of the element within this stream. The stream index may or may not be equal to any other indexes the element itself thinks it posesses.

The index value is initially -1, indicating no element. After first next() call, index becomes 0, then 1, and so on. This functionality resembles java.sql.resultSet#getRow method functionality, but with the difference that the index counter starts from 0, not 1.

Specified by:

getIndex in interface DataStream

Returns:

element index

hasNext

public boolean hasNext()

Tests if the stream still contains data.

Specified by:

hasNext in interface DataStream

Returns:

true if it does.

next

public DataValue next()
               throws InvalidDataException

Gets the next data from the stream.

Specified by:

next in interface DataStream

Throws:

InvalidDataException - if the collection content does not satisfy the given type.