Package com.apple.foundationdb.record.provider.foundationdb

Class SplitHelper.KeyValueUnsplitter

java.lang.Object

com.apple.foundationdb.record.provider.foundationdb.SplitHelper.KeyValueUnsplitter

All Implemented Interfaces:

BaseCursor<com.apple.foundationdb.record.provider.foundationdb.FDBRawRecord>, RecordCursor<com.apple.foundationdb.record.provider.foundationdb.FDBRawRecord>, AutoCloseable, Iterator<com.apple.foundationdb.record.provider.foundationdb.FDBRawRecord>

Enclosing class:

SplitHelper

public static class SplitHelper.KeyValueUnsplitter
extends Object
implements BaseCursor<com.apple.foundationdb.record.provider.foundationdb.FDBRawRecord>

This cursor may exceed out-of-band limits in order to ensure that it only ever stops in between (split) records. It is therefore unusual since it may exceed the record scan limit arbitrarily based on the size of the record and the maximum value size.

Nested Class Summary

Nested classes/interfaces inherited from interface com.apple.foundationdb.record.RecordCursor

RecordCursor.NoNextReason

Constructor Summary

Constructors

Constructor	Description
KeyValueUnsplitter(FDBRecordContext context, Subspace subspace, RecordCursor<KeyValue> inner, boolean oldVersionFormat, SplitHelper.SizeInfo sizeInfo, boolean reverse, CursorLimitManager limitManager)
KeyValueUnsplitter(FDBRecordContext context, Subspace subspace, RecordCursor<KeyValue> inner, boolean oldVersionFormat, SplitHelper.SizeInfo sizeInfo, ScanProperties scanProperties)

Method Summary

Modifier and Type	Method	Description
boolean	accept(RecordCursorVisitor visitor)	Accept a visit from hierarchical visitor, which implements RecordCursorVisitor.
protected boolean	append(RecordCursorResult<KeyValue> resultWithKv)
void	close()
byte[]	getContinuation()	Deprecated.
Executor	getExecutor()
RecordCursorResult<com.apple.foundationdb.record.provider.foundationdb.FDBRawRecord>	getNext()	Get the next result from this cursor.
RecordCursor.NoNextReason	getNoNextReason()	Deprecated.
boolean	hasNext()	Deprecated.
RecordCursor.NoNextReason	mergeNoNextReason()
com.apple.foundationdb.record.provider.foundationdb.FDBRawRecord	next()	Deprecated.
CompletableFuture<Boolean>	onHasNext()	Deprecated.
CompletableFuture<RecordCursorResult<com.apple.foundationdb.record.provider.foundationdb.FDBRawRecord>>	onNext()	Asynchronously return the next result from this cursor.

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.util.Iterator

forEachRemaining, remove

Methods inherited from interface com.apple.foundationdb.record.RecordCursor

asIterator, asList, filter, filterAsync, filterAsyncInstrumented, filterAsyncInstrumented, filterInstrumented, filterInstrumented, first, flatMapPipelined, forEach, forEachAsync, forEachResult, forEachResultAsync, getCount, limitRowsTo, limitTo, map, mapEffect, mapEffect, mapPipelined, orElse, reduce, skip, skipThenLimit

Constructor Detail

KeyValueUnsplitter

public KeyValueUnsplitter(@Nonnull
                          FDBRecordContext context,
                          @Nonnull
                          Subspace subspace,
                          @Nonnull
                          RecordCursor<KeyValue> inner,
                          boolean oldVersionFormat,
                          @Nullable
                          SplitHelper.SizeInfo sizeInfo,
                          @Nonnull
                          ScanProperties scanProperties)

KeyValueUnsplitter

public KeyValueUnsplitter(@Nonnull
                          FDBRecordContext context,
                          @Nonnull
                          Subspace subspace,
                          @Nonnull
                          RecordCursor<KeyValue> inner,
                          boolean oldVersionFormat,
                          @Nullable
                          SplitHelper.SizeInfo sizeInfo,
                          boolean reverse,
                          @Nonnull
                          CursorLimitManager limitManager)

Method Detail

onNext

@Nonnull
public CompletableFuture<RecordCursorResult<com.apple.foundationdb.record.provider.foundationdb.FDBRawRecord>> onNext()

Description copied from interface: RecordCursor

Asynchronously return the next result from this cursor. When complete, the future will contain a RecordCursorResult, which represents exactly one of the following:

1. The next object of type T produced by the cursor. In addition to the next record, this result includes a RecordCursorContinuation that can be used to continue the cursor after the last record returned. The returned continuation is guaranteed not to be an "end continuation" representing the end of the cursor: specifically, RecordCursorContinuation.isEnd() is always false on the returned continuation.
2. The fact that the cursor is stopped and cannot produce another record and a RecordCursor.NoNextReason that explains why no record could be produced. The result include a continuation that can be used to continue the cursor after the last record returned. If the result's NoNextReason is anything other than RecordCursor.NoNextReason.SOURCE_EXHAUSTED, the returned continuation must not be an end continuation. Conversely, if the result's NoNextReason is SOURCE_EXHAUSTED, then the returned continuation must be an an "end continuation".

In either case, the returned RecordCursorContinuation can be serialized to an opaque byte array using RecordCursorContinuation.toBytes(). This can be passed back into a new cursor of the same type, with all other parameters remaining the same.

Specified by:

onNext in interface RecordCursor<com.apple.foundationdb.record.provider.foundationdb.FDBRawRecord>

Returns:

a future for the next result from this cursor representing either the next record or an indication of why the cursor stopped

See Also:

RecordCursorResult, RecordCursorContinuation

getNext

@Nonnull
public RecordCursorResult<com.apple.foundationdb.record.provider.foundationdb.FDBRawRecord> getNext()

Description copied from interface: RecordCursor

Get the next result from this cursor. In many cases, this is a blocking operation and should not be called within asynchronous contexts. The non-blocking version of this function, RecordCursor.onNext(), should be preferred in such circumstances.

Specified by:

getNext in interface RecordCursor<com.apple.foundationdb.record.provider.foundationdb.FDBRawRecord>

Returns:

the next result from this cursor representing either the next record or an indication of why the cursor stopped

See Also:

RecordCursor.onNext(), RecordCursorResult, RecordCursorContinuation

onHasNext

@Nonnull
@Deprecated
public CompletableFuture<Boolean> onHasNext()

Deprecated.

Description copied from interface: RecordCursor

Asynchronously check whether there are more records available from the cursor.

Specified by:

onHasNext in interface RecordCursor<com.apple.foundationdb.record.provider.foundationdb.FDBRawRecord>

Returns:

a future that when complete will hold true if RecordCursor.next() would return a record.

See Also:

AsyncIterator.onHasNext()

hasNext

@Deprecated
public boolean hasNext()

Deprecated.

Description copied from interface: RecordCursor

Synchronously check whether there are more records available from the cursor.

Specified by:

hasNext in interface Iterator<com.apple.foundationdb.record.provider.foundationdb.FDBRawRecord>

Specified by:

hasNext in interface RecordCursor<com.apple.foundationdb.record.provider.foundationdb.FDBRawRecord>

Returns:

true if RecordCursor.next() would return a record and false otherwise

next

@Nullable
@Deprecated
public com.apple.foundationdb.record.provider.foundationdb.FDBRawRecord next()

Deprecated.

Description copied from interface: RecordCursor

Return the next value.

Specified by:

next in interface Iterator<com.apple.foundationdb.record.provider.foundationdb.FDBRawRecord>

Specified by:

next in interface RecordCursor<com.apple.foundationdb.record.provider.foundationdb.FDBRawRecord>

Returns:

the next value

getContinuation

@Nullable
@Deprecated
public byte[] getContinuation()

Deprecated.

Description copied from interface: RecordCursor

Get a byte string that can be used to continue a query after the last record returned.

Specified by:

getContinuation in interface RecordCursor<com.apple.foundationdb.record.provider.foundationdb.FDBRawRecord>

Returns:

opaque byte array denoting where the cursor should pick up. This can be passed back into a new cursor of the same type, with all other parameters remaining the same. Returns null if the underlying source is completely exhausted, independent of any limit passed to the cursor creator. Since such creators generally accept null to mean no continuation, that is, start from the beginning, one must check for null from getContinuation to keep from starting over. Result is not always defined if called before onHasNext or before next after onHasNext has returned true. That is, a continuation is only guaranteed when called "between" records from a while (hasNext) next loop or after its end.

getNoNextReason

@Nonnull
@Deprecated
public RecordCursor.NoNextReason getNoNextReason()

Deprecated.

Description copied from interface: RecordCursor

Get the reason that the cursor has reached the end and returned false for RecordCursor.hasNext(). If hasNext was not called or returned true last time, the result is undefined and may be an exception.

Specified by:

getNoNextReason in interface RecordCursor<com.apple.foundationdb.record.provider.foundationdb.FDBRawRecord>

Returns:

the reason that the cursor stopped

mergeNoNextReason

@Nonnull
public RecordCursor.NoNextReason mergeNoNextReason()

close

public void close()

Specified by:

close in interface AutoCloseable

Specified by:

close in interface RecordCursor<com.apple.foundationdb.record.provider.foundationdb.FDBRawRecord>

getExecutor

@Nonnull
public Executor getExecutor()

Specified by:

getExecutor in interface RecordCursor<com.apple.foundationdb.record.provider.foundationdb.FDBRawRecord>

accept

public boolean accept(@Nonnull
                      RecordCursorVisitor visitor)

Description copied from interface: RecordCursor

Accept a visit from hierarchical visitor, which implements RecordCursorVisitor. By contract, implementations of this method must return the value of visitor.visitLeave(this), which determines whether or not subsequent siblings of this cursor should be visited.

Specified by:

accept in interface RecordCursor<com.apple.foundationdb.record.provider.foundationdb.FDBRawRecord>

Parameters:

visitor - a hierarchical visitor

Returns:

true if the subsequent siblings of the cursor should be visited, and false otherwise

append

protected boolean append(@Nonnull
                         RecordCursorResult<KeyValue> resultWithKv)