com.davisor.data.stream
Class ProxyDataBuffer.ProxyDataStream

java.lang.Object
  com.davisor.data.stream.ProxyDataBuffer.ProxyDataStream

All Implemented Interfaces:

Data, DataStream

Enclosing class:

ProxyDataBuffer

public class ProxyDataBuffer.ProxyDataStream

extends java.lang.Object

implements DataStream

ProxyDataStream implements a single column view to a multi column stream.

Field Summary

protected DataStream	M_dataStream The data stream this proxy refers to.
protected boolean	M_reversed Controls if stream reads buffer forwards or backwards.

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

INITIAL_INDEX

Constructor Summary

ProxyDataBuffer.ProxyDataStream(boolean reversed)
Creates a new proxy data stream.

ProxyDataBuffer.ProxyDataStream(boolean reversed, long index)
Creates a new proxy data stream that starts reading data from given stream position.

Method Summary

boolean	close() Dummy implementation for buffer case.
long	getIndex() Retrieves the index number of the element returned by the latest next() call.
java.lang.Object	getMetaData() Deprecated. replaced with Type.getMetaData()
Type	getType() Gets the type of this data object.
boolean	hasNext() Tests if the stream still contains data.
DataValue	next() Gets the next data from the stream.
void	setMetaData(java.lang.Object metaData) Deprecated. replaced with Type.setMetaData(Map)

Methods inherited from class java.lang.Object

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

Field Detail

M_dataStream

protected DataStream M_dataStream

The data stream this proxy refers to.

M_reversed

protected boolean M_reversed

Controls if stream reads buffer forwards or backwards.

Constructor Detail

ProxyDataBuffer.ProxyDataStream

public ProxyDataBuffer.ProxyDataStream(boolean reversed)
                                throws InvalidDataException

Creates a new proxy data stream.

Parameters:

reversed - controls if stream reads buffer forwards or backwards

Throws:

java.lang.NullPointerException - if the source buffer is null

InvalidDataException

ProxyDataBuffer.ProxyDataStream

public ProxyDataBuffer.ProxyDataStream(boolean reversed,
                                       long index)
                                throws InvalidDataException

Creates a new proxy data stream that starts reading data from given stream position.

Parameters:

reversed - controls if stream reads buffer forwards or backwards

index - number of elements to skip from the head of the stream

Throws:

java.lang.NullPointerException - if the source buffer is null

InvalidDataException

Method Detail

close

public boolean close()

Dummy implementation for buffer case.

Specified by:

close in interface DataStream

Returns:

if stream closing was successfull or not

See Also:

DataStream.hasNext()

getType

public Type getType()
             throws InvalidDataException

Gets the type of this data object.

Specified by:

getType in interface Data

Returns:

the type associated with this data object

Throws:

java.lang.ClassCastException - if a target type could not be resolved

InvalidDataException - if type retrieval fails

java.lang.NullPointerException - if the source buffer is null

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

Throws:

java.lang.NullPointerException - if the source buffer is null

getMetaData

public java.lang.Object getMetaData()

Deprecated. replaced with Type.getMetaData()

Gets the data stream meta data.

This method does nothing as it would be impossible to implement because the underlying and now deprecated meta data mechanism does not allow meta data to be assosiated to any particular stream column.

Returns:

always null

hasNext

public boolean hasNext()

Tests if the stream still contains data.

Specified by:

hasNext in interface DataStream

Returns:

true if it does.

Throws:

java.lang.NullPointerException - if the source buffer is null

next

public DataValue next()
               throws InvalidDataException

Gets the next data from the stream.

Specified by:

next in interface DataStream

Throws:

InvalidDataException - if no data element could be retrieved

java.lang.NullPointerException - if the source buffer is null

setMetaData

public void setMetaData(java.lang.Object metaData)

Deprecated. replaced with Type.setMetaData(Map)

Sets the data stream meta data.

This method does nothing as it would be impossible to implement because the underlying and now deprecated meta data mechanism does not allow meta data to be assosiated to any particular column.

Parameters:

metaData - an application spesific meta data object