org.corfudb.runtime.view.stream

Interface IStreamView

All Superinterfaces:

Iterator<ILogData>

All Known Implementing Classes:

AbstractContextStreamView, AbstractQueuedStreamView, AddressMapStreamView, BackpointerStreamView, ThreadSafeStreamView

public interface IStreamView
extends Iterator<ILogData>

This interface represents a view on a stream. A stream is an ordered set of log entries which can only be appended to and read in sequential order.

Created by mwei on 1/5/17.

Nested Class Summary

Nested Classes

Modifier and Type	Interface and Description
static class	IStreamView.SearchDirection An enum representing search directions.

Method Summary

Modifier and Type	Method and Description
default long	append(Object object) Append an object to the stream, returning the global address it was written at.
long	append(Object object, Function<TokenResponse,Boolean> acquisitionCallback, Function<TokenResponse,Boolean> deacquisitionCallback) Append an object to the stream, returning the global address it was written at.
ILogData	current() Retrieve the current entry in the stream, which was the entry previously returned by a call to next() or previous().
long	find(long globalAddress, IStreamView.SearchDirection direction) Find the global address of the next entry in this stream, in the direction given.
void	gc(long trimMark) Garbage collect all the trimmed entries on this stream
long	getCurrentGlobalPosition() Get the current position of the pointer in this stream (global address).
UUID	getId() Return the ID of the stream this view is for.
long	getTotalUpdates() Get total number of updates registered to this stream.
boolean	hasNext() Returns whether or not there are potentially more entries in this stream - this function may return true even if there are no entries remaining, as addresses may have been acquired by other clients but not written yet, or the addresses were hole-filled, or just failed.
default ILogData	next() Retrieve the next entry from this stream, up to the tail of the stream If there are no entries present, this function will return NULL.
ILogData	nextUpTo(long maxGlobal) Retrieve the next entry from this stream, up to the address given or the tail of the stream.
ILogData	previous() Retrieve the previous entry in the stream.
default List<ILogData>	remaining() Retrieve all of the entries from this stream, up to the tail of this stream.
List<ILogData>	remainingUpTo(long maxGlobal) Retrieve all of the entries from this stream, up to the address given or the tail of the stream.
void	reset() Reset the state of this stream view, causing the next read to start from the beginning of this stream.
void	seek(long globalAddress) Seek to the requested maxGlobal address.
default Spliterator<ILogData>	spliterator() Get a spliterator for this stream view
default Spliterator<ILogData>	spliteratorUpTo(long maxGlobal) Get a spliterator for this stream view, limiting the return values to a specified global address.
default Stream<ILogData>	stream() Get a Java stream from this stream view.
default Stream<ILogData>	streamUpTo(long maxGlobal) Get a Java stream from this stream view, limiting reads to a specified global address.

Methods inherited from interface java.util.Iterator

forEachRemaining, remove

Method Detail

getId

UUID getId()

Return the ID of the stream this view is for.

Returns:

The ID of the stream.

reset

void reset()

Reset the state of this stream view, causing the next read to start from the beginning of this stream.

gc

void gc(long trimMark)

Garbage collect all the trimmed entries on this stream

Parameters:

trimMark - start of the active log

seek

void seek(long globalAddress)

Seek to the requested maxGlobal address. The next read will begin at the given global address, inclusive.

Parameters:

globalAddress - Address to seek to

find

long find(long globalAddress,
          IStreamView.SearchDirection direction)

Find the global address of the next entry in this stream, in the direction given.

Parameters:

globalAddress - The global address to start searching from.

direction - The direction to search.

Returns:

The global address of the next entry in the stream, or Address.NOT_FOUND if no entry was found.

append

long append(Object object,
            Function<TokenResponse,Boolean> acquisitionCallback,
            Function<TokenResponse,Boolean> deacquisitionCallback)

Append an object to the stream, returning the global address it was written at.

Optionally, provide a method to be called when an address is acquired, and also a method to be called when an address is released (due to an unsuccessful append).

Parameters:

object - The object to append.

acquisitionCallback - A function to call when an address is acquired. It should return true to continue with the append.

deacquisitionCallback - A function to call when an address is released. It should return true to retry writing.

Returns:

The (global) address the object was written at.

append

default long append(Object object)

Append an object to the stream, returning the global address it was written at.

Parameters:

object - Object to append/write

Returns:

The (global) address the object was written at.

next

@Nullable
default ILogData next()

Retrieve the next entry from this stream, up to the tail of the stream If there are no entries present, this function will return NULL. If there are holes present in the log, they will be filled.

Specified by:

next in interface Iterator<ILogData>

Returns:

The next entry in the stream, or NULL, if no entries are available.

previous

@Nullable
ILogData previous()

Retrieve the previous entry in the stream. If there are no previous entries, NULL will be returned.

Returns:

The previous entry in the stream, or NULL, if no entries are available.

current

@Nullable
ILogData current()

Retrieve the current entry in the stream, which was the entry previously returned by a call to next() or previous(). If the stream was never read from, NULL will be returned.

Returns:

The current entry in the stream.

nextUpTo

@Nullable
ILogData nextUpTo(long maxGlobal)

Retrieve the next entry from this stream, up to the address given or the tail of the stream. If there are no entries present, this function will return NULL. If there are holes present in the log, they will be filled.

Parameters:

maxGlobal - The maximum global address to read up to.

Returns:

The next entry in the stream, or NULL, if no entries are available.

remaining

@Nonnull
default List<ILogData> remaining()

Retrieve all of the entries from this stream, up to the tail of this stream. If there are no entries present, this function will return an empty list. If there are holes present in the log, they will be filled.

Note: the default implementation is thread-safe only if the implementation of read is synchronized.

Returns:

The next entries in the stream, or an empty list, if no entries are available.

remainingUpTo

List<ILogData> remainingUpTo(long maxGlobal)

Retrieve all of the entries from this stream, up to the address given or the tail of the stream. If there are no entries present, this function will return an empty list. If there are holes present in the log, they will be filled.

Parameters:

maxGlobal - The maximum global address to read up to.

Returns:

The next entries in the stream, or an empty list, if no entries are available.

hasNext

boolean hasNext()

Returns whether or not there are potentially more entries in this stream - this function may return true even if there are no entries remaining, as addresses may have been acquired by other clients but not written yet, or the addresses were hole-filled, or just failed.

Specified by:

hasNext in interface Iterator<ILogData>

Returns:

True, if there are potentially more entries in the stream.

getCurrentGlobalPosition

long getCurrentGlobalPosition()

Get the current position of the pointer in this stream (global address).

Returns:

The position of the pointer in this stream (global address), or Address.NON_ADDRESS.

spliterator

default Spliterator<ILogData> spliterator()

Get a spliterator for this stream view

Returns:

A spliterator for this stream view.

spliteratorUpTo

default Spliterator<ILogData> spliteratorUpTo(long maxGlobal)

Get a spliterator for this stream view, limiting the return values to a specified global address.

Parameters:

maxGlobal - The maximum global address to read to

Returns:

A spliterator for this stream view.

stream

default Stream<ILogData> stream()

Get a Java stream from this stream view.

Returns:

A Java stream for this stream view.

streamUpTo

default Stream<ILogData> streamUpTo(long maxGlobal)

Get a Java stream from this stream view, limiting reads to a specified global address.

Parameters:

maxGlobal - The maximum global address to read to.

Returns:

A spliterator for this stream view.

getTotalUpdates

long getTotalUpdates()

Get total number of updates registered to this stream.

Returns:

total number of updates belonging to this stream.