org.apache.bookkeeper.mledger

Interface ReadOnlyCursor

All Known Implementing Classes:

ReadOnlyCursorImpl

@InterfaceAudience.LimitedPrivate
 @InterfaceStability.Stable
public interface ReadOnlyCursor

Method Summary

Modifier and Type	Method and Description
void	asyncClose(AsyncCallbacks.CloseCallback callback, Object ctx) Close the cursor asynchronously and release the associated resources.
void	asyncReadEntries(int numberOfEntriesToRead, AsyncCallbacks.ReadEntriesCallback callback, Object ctx, PositionImpl maxPosition) Asynchronously read entries from the ManagedLedger.
void	asyncReadEntries(int numberOfEntriesToRead, long maxSizeBytes, AsyncCallbacks.ReadEntriesCallback callback, Object ctx, PositionImpl maxPosition) Asynchronously read entries from the ManagedLedger.
void	close() Close the cursor and releases the associated resources.
Position	findNewestMatching(ManagedCursor.FindPositionConstraint constraint, com.google.common.base.Predicate<Entry> condition) Find the newest entry that matches the given predicate.
long	getNumberOfEntries() Return the number of messages that this cursor still has to read.
long	getNumberOfEntries(com.google.common.collect.Range<PositionImpl> range) Return the number of messages that this cursor still has to read.
Position	getReadPosition() Get the read position.
boolean	hasMoreEntries() Tells whether this cursor has already consumed all the available entries.
List<Entry>	readEntries(int numberOfEntriesToRead) Read entries from the ManagedLedger, up to the specified number.
void	skipEntries(int numEntriesToSkip) Skip n entries from the read position of this cursor.

Method Detail

readEntries

List<Entry> readEntries(int numberOfEntriesToRead)
                 throws InterruptedException,
                        ManagedLedgerException

Read entries from the ManagedLedger, up to the specified number. The returned list can be smaller.

Parameters:

numberOfEntriesToRead - maximum number of entries to return

Returns:

the list of entries

Throws:

ManagedLedgerException

InterruptedException

asyncReadEntries

void asyncReadEntries(int numberOfEntriesToRead,
                      AsyncCallbacks.ReadEntriesCallback callback,
                      Object ctx,
                      PositionImpl maxPosition)

Asynchronously read entries from the ManagedLedger.

Parameters:

numberOfEntriesToRead - maximum number of entries to return

callback - callback object

ctx - opaque context

maxPosition - max position can read

See Also:

readEntries(int)

asyncReadEntries

void asyncReadEntries(int numberOfEntriesToRead,
                      long maxSizeBytes,
                      AsyncCallbacks.ReadEntriesCallback callback,
                      Object ctx,
                      PositionImpl maxPosition)

Asynchronously read entries from the ManagedLedger.

Parameters:

numberOfEntriesToRead - maximum number of entries to return

maxSizeBytes - max size in bytes of the entries to return

callback - callback object

ctx - opaque context

maxPosition - max position can read

getReadPosition

Position getReadPosition()

Get the read position. This points to the next message to be read from the cursor.

Returns:

the read position

hasMoreEntries

boolean hasMoreEntries()

Tells whether this cursor has already consumed all the available entries.

This method is not blocking.

Returns:

true if there are pending entries to read, false otherwise

getNumberOfEntries

long getNumberOfEntries()

Return the number of messages that this cursor still has to read.

This method has linear time complexity on the number of ledgers included in the managed ledger.

Returns:

the number of entries

skipEntries

void skipEntries(int numEntriesToSkip)

Skip n entries from the read position of this cursor.

Parameters:

numEntriesToSkip - number of entries to skip

findNewestMatching

Position findNewestMatching(ManagedCursor.FindPositionConstraint constraint,
                            com.google.common.base.Predicate<Entry> condition)
                     throws InterruptedException,
                            ManagedLedgerException

Find the newest entry that matches the given predicate.

Parameters:

constraint - search only active entries or all entries

condition - predicate that reads an entry an applies a condition

Returns:

Position of the newest entry that matches the given predicate

Throws:

InterruptedException

ManagedLedgerException

getNumberOfEntries

long getNumberOfEntries(com.google.common.collect.Range<PositionImpl> range)

Return the number of messages that this cursor still has to read.

This method has linear time complexity on the number of ledgers included in the managed ledger.

Parameters:

range - the range between two positions

Returns:

the number of entries in range

close

void close()
    throws InterruptedException,
           ManagedLedgerException

Close the cursor and releases the associated resources.

Throws:

InterruptedException

ManagedLedgerException

asyncClose

void asyncClose(AsyncCallbacks.CloseCallback callback,
                Object ctx)

Close the cursor asynchronously and release the associated resources.

Parameters:

callback - callback object

ctx - opaque context