io.github.privacystreams.core

Class Stream

java.lang.Object

io.github.privacystreams.core.Stream

Direct Known Subclasses:

PStream

public abstract class Stream
extends java.lang.Object

Stream is one of the essential classes used in PrivacyStreams. Most personal data access/process operation in PrivacyStreams use Stream as the intermediate. A Stream is consist of one or multiple items. The items are produced by PStreamProvider functions (like LocationUpdatesProvider, CallLogProvider, etc.), transformed by PStreamTransformation functions (like filter, reorder, map, etc.), and outputted by ItemsOperator functions (like print, toList, etc.). Stream producer functions (including PStreamProvider and PStreamTransformation) should make sure the stream is not closed before writing items to it, using: stream.isClosed() Stream consumer functions (including PStreamTransformation and ItemsOperator) should stop reading from Stream if the stream is ended. If stream.read() returns a null, it means the stream is ended.

Method Summary

Modifier and Type	Method and Description
abstract Function<java.lang.Void,? extends Stream>	getStreamProvider()
UQI	getUQI()
boolean	isClosed() Check whether the stream is closed, Stream generator functions should make sure the stream is not closed this writing items to it.
void	register(Function<? extends Stream,?> streamReceiver) Register a function to current stream.
Stream	reuse(int numOfReuses)
java.util.Map<java.lang.String,java.lang.Object>	toMap()
java.lang.String	toString()
void	unregister(Function<? extends Stream,?> streamReceiver) Unregister a function from current stream.
void	write(Item item, Function<?,? extends Stream> streamProvider) Write an item to the stream, or write a null to end the stream.

Methods inherited from class java.lang.Object

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

Method Detail

write

public void write(Item item,
                  Function<?,? extends Stream> streamProvider)

Write an item to the stream, or write a null to end the stream.

Parameters:

item - the item to write to the stream, null indicates the end of the stream

streamProvider - the function that provide current stream

register

public void register(Function<? extends Stream,?> streamReceiver)

Register a function to current stream.

Parameters:

streamReceiver - the function that receives stream items

unregister

public void unregister(Function<? extends Stream,?> streamReceiver)

Unregister a function from current stream.

Parameters:

streamReceiver - the function that receives stream items

isClosed

public boolean isClosed()

Check whether the stream is closed, Stream generator functions should make sure the stream is not closed this writing items to it.

Returns:

true if the stream is closed, meaning the stream does not accept new items

getStreamProvider

public abstract Function<java.lang.Void,? extends Stream> getStreamProvider()

toMap

public java.util.Map<java.lang.String,java.lang.Object> toMap()

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object

getUQI

public UQI getUQI()

reuse

public Stream reuse(int numOfReuses)