org.apache.ignite.internal.processors.cache.persistence.wal

Class AbstractWalRecordsIterator

java.lang.Object

org.apache.ignite.internal.util.lang.GridIteratorAdapter<T>

org.apache.ignite.internal.util.GridCloseableIteratorAdapter<IgniteBiTuple<WALPointer,WALRecord>>

org.apache.ignite.internal.processors.cache.persistence.wal.AbstractWalRecordsIterator

All Implemented Interfaces:

Serializable, AutoCloseable, Iterable<IgniteBiTuple<WALPointer,WALRecord>>, Iterator<IgniteBiTuple<WALPointer,WALRecord>>, WALIterator, GridSerializableIterator<IgniteBiTuple<WALPointer,WALRecord>>, GridCloseableIterator<IgniteBiTuple<WALPointer,WALRecord>>, GridIterator<IgniteBiTuple<WALPointer,WALRecord>>, IgniteSpiCloseableIterator<IgniteBiTuple<WALPointer,WALRecord>>

Direct Known Subclasses:

SingleSegmentLogicalRecordsIterator

public abstract class AbstractWalRecordsIterator
extends GridCloseableIteratorAdapter<IgniteBiTuple<WALPointer,WALRecord>>
implements WALIterator

Iterator over WAL segments. This abstract class provides most functionality for reading records in log. Subclasses are to override segment switching functionality

See Also:

Serialized Form

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
protected static interface	AbstractWalRecordsIterator.AbstractFileDescriptor
protected static interface	AbstractWalRecordsIterator.AbstractReadFileHandle

Field Summary

Fields

Modifier and Type	Field and Description
protected IgniteBiTuple<WALPointer,WALRecord>	curRec Current record preloaded, to be returned on next() Normally this should be not null because advance() method should already prepare some value
protected long	curWalSegmIdx Current WAL segment absolute index.
protected @NotNull FileIOFactory	ioFactory Factory to provide I/O interfaces for read/write operations with files
protected @NotNull IgniteLogger	log Logger
protected @NotNull GridCacheSharedContext	sharedCtx Shared context for creating serializer of required version and grid name access.

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	AbstractWalRecordsIterator(@NotNull IgniteLogger log, @NotNull GridCacheSharedContext sharedCtx, @NotNull RecordSerializerFactory serializerFactory, @NotNull FileIOFactory ioFactory, int initialReadBufferSize, SegmentFileInputFactory segmentFileInputFactory)

Method Summary

Modifier and Type	Method and Description
protected void	advance() Switches records iterator to the next record.
protected IgniteBiTuple<WALPointer,WALRecord>	advanceRecord(@Nullable AbstractWalRecordsIterator.AbstractReadFileHandle hnd) Switches to new record.
protected abstract AbstractWalRecordsIterator.AbstractReadFileHandle	advanceSegment(@Nullable AbstractWalRecordsIterator.AbstractReadFileHandle curWalSegment) Switches records iterator to the next WAL segment as result of this method, new reference to segment should be returned.
protected @Nullable AbstractWalRecordsIterator.AbstractReadFileHandle	closeCurrentWalSegment() Closes and returns WAL segment (if any)
protected abstract AbstractWalRecordsIterator.AbstractReadFileHandle	createReadFileHandle(SegmentIO fileIO, RecordSerializer ser, FileInput in)
protected IgniteCheckedException	handleRecordException(@NotNull Exception e, @Nullable WALPointer ptr) Handler for record deserialization exception.
protected AbstractWalRecordsIterator.AbstractReadFileHandle	initReadHandle(@NotNull AbstractWalRecordsIterator.AbstractFileDescriptor desc, @Nullable WALPointer start) Assumes file descriptor will be opened in this method.
protected AbstractWalRecordsIterator.AbstractReadFileHandle	initReadHandle(@NotNull AbstractWalRecordsIterator.AbstractFileDescriptor desc, @Nullable WALPointer start, @NotNull SegmentIO fileIO, @NotNull SegmentHeader segmentHeader) Assumes fileIO will be closed in this method in case of error occurred.
Optional<WALPointer>	lastRead()
protected void	onClose() Invoked on iterator close.
protected boolean	onHasNext()
protected IgniteBiTuple<WALPointer,WALRecord>	onNext()
protected @NotNull WALRecord	postProcessRecord(@NotNull WALRecord rec) Performs final conversions with record loaded from WAL.
protected IgniteCheckedException	validateTailReachedException(WalSegmentTailReachedException tailReachedException, AbstractWalRecordsIterator.AbstractReadFileHandle currWalSegment)

Methods inherited from class org.apache.ignite.internal.util.GridCloseableIteratorAdapter

checkClosed, close, hasNextX, isClosed, nextX, onRemove, removeX

Methods inherited from class org.apache.ignite.internal.util.lang.GridIteratorAdapter

hasNext, iterator, next, remove

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.apache.ignite.internal.util.lang.GridCloseableIterator

close, isClosed

Methods inherited from interface org.apache.ignite.internal.util.lang.GridIterator

hasNextX, nextX, removeX

Methods inherited from interface java.lang.Iterable

forEach, iterator, spliterator

Methods inherited from interface java.util.Iterator

forEachRemaining, hasNext, next, remove

Field Detail

curRec

protected IgniteBiTuple<WALPointer,WALRecord> curRec

Current record preloaded, to be returned on next()
Normally this should be not null because advance() method should already prepare some value

curWalSegmIdx

protected long curWalSegmIdx

Current WAL segment absolute index.
Determined as lowest number of file at start, is changed during advance segment

log

@NotNull
protected final @NotNull IgniteLogger log

Logger

sharedCtx

@NotNull
protected final @NotNull GridCacheSharedContext sharedCtx

Shared context for creating serializer of required version and grid name access. Also cacheObjects processor from this context may be used to covert Data entry key and value from its binary representation into objects.

ioFactory

@NotNull
protected final @NotNull FileIOFactory ioFactory

Factory to provide I/O interfaces for read/write operations with files

Constructor Detail

AbstractWalRecordsIterator

protected AbstractWalRecordsIterator(@NotNull
                                     @NotNull IgniteLogger log,
                                     @NotNull
                                     @NotNull GridCacheSharedContext sharedCtx,
                                     @NotNull
                                     @NotNull RecordSerializerFactory serializerFactory,
                                     @NotNull
                                     @NotNull FileIOFactory ioFactory,
                                     int initialReadBufferSize,
                                     SegmentFileInputFactory segmentFileInputFactory)

Parameters:

log - Logger.

sharedCtx - Shared context.

serializerFactory - Serializer of current version to read headers.

ioFactory - ioFactory for file IO access.

initialReadBufferSize - buffer for reading records size.

segmentFileInputFactory - Factory to provide I/O interfaces for read primitives with files.

Method Detail

onNext

protected IgniteBiTuple<WALPointer,WALRecord> onNext()
                                              throws IgniteCheckedException

Specified by:

onNext in class GridCloseableIteratorAdapter<IgniteBiTuple<WALPointer,WALRecord>>

Returns:

Next element.

Throws:

IgniteCheckedException - If failed.

onHasNext

protected boolean onHasNext()
                     throws IgniteCheckedException

Specified by:

onHasNext in class GridCloseableIteratorAdapter<IgniteBiTuple<WALPointer,WALRecord>>

Returns:

True if iterator has next element.

Throws:

IgniteCheckedException - If failed.

onClose

protected void onClose()
                throws IgniteCheckedException

Invoked on iterator close.

Overrides:

onClose in class GridCloseableIteratorAdapter<IgniteBiTuple<WALPointer,WALRecord>>

Throws:

IgniteCheckedException - If closing failed.

advance

protected void advance()
                throws IgniteCheckedException

Switches records iterator to the next record.

• curRec will be updated.
• If end of segment reached, switch to new segment is called. currWalSegment will be updated.

advance() runs a step ahead GridIteratorAdapter.next()

Throws:

IgniteCheckedException - If failed.

lastRead

public Optional<WALPointer> lastRead()

Specified by:

lastRead in interface WALIterator

Returns:

Pointer of last read valid record. Empty if no records were read.

validateTailReachedException

protected IgniteCheckedException validateTailReachedException(WalSegmentTailReachedException tailReachedException,
                                                              AbstractWalRecordsIterator.AbstractReadFileHandle currWalSegment)

Parameters:

tailReachedException - Tail reached exception.

currWalSegment - Current WAL segment read handler.

Returns:

If need to throw exception after validation.

closeCurrentWalSegment

@Nullable
protected @Nullable AbstractWalRecordsIterator.AbstractReadFileHandle closeCurrentWalSegment()
                                                                                                throws IgniteCheckedException

Closes and returns WAL segment (if any)

Returns:

closed handle

Throws:

IgniteCheckedException - if IO failed

advanceSegment

protected abstract AbstractWalRecordsIterator.AbstractReadFileHandle advanceSegment(@Nullable
                                                                                    @Nullable AbstractWalRecordsIterator.AbstractReadFileHandle curWalSegment)
                                                                             throws IgniteCheckedException

Switches records iterator to the next WAL segment as result of this method, new reference to segment should be returned. Null for current handle means stop of iteration.

Parameters:

curWalSegment - current open WAL segment or null if there is no open segment yet

Returns:

new WAL segment to read or null for stop iteration

Throws:

IgniteCheckedException - if reading failed

advanceRecord

protected IgniteBiTuple<WALPointer,WALRecord> advanceRecord(@Nullable
                                                            @Nullable AbstractWalRecordsIterator.AbstractReadFileHandle hnd)
                                                     throws IgniteCheckedException

Switches to new record.

Parameters:

hnd - currently opened read handle.

Returns:

next advanced record.

Throws:

IgniteCheckedException

postProcessRecord

@NotNull
protected @NotNull WALRecord postProcessRecord(@NotNull
                                                        @NotNull WALRecord rec)

Performs final conversions with record loaded from WAL. To be overridden by subclasses if any processing required.

Parameters:

rec - record to post process.

Returns:

post processed record.

handleRecordException

protected IgniteCheckedException handleRecordException(@NotNull
                                                       @NotNull Exception e,
                                                       @Nullable
                                                       @Nullable WALPointer ptr)

Handler for record deserialization exception.

Parameters:

e - problem from records reading

ptr - file pointer was accessed

Returns:

null if the error was handled and we can go ahead, IgniteCheckedException if the error was not handled, and we should stop the iteration.

initReadHandle

protected AbstractWalRecordsIterator.AbstractReadFileHandle initReadHandle(@NotNull
                                                                           @NotNull AbstractWalRecordsIterator.AbstractFileDescriptor desc,
                                                                           @Nullable
                                                                           @Nullable WALPointer start,
                                                                           @NotNull
                                                                           @NotNull SegmentIO fileIO,
                                                                           @NotNull
                                                                           @NotNull SegmentHeader segmentHeader)
                                                                    throws IgniteCheckedException

Assumes fileIO will be closed in this method in case of error occurred.

Parameters:

desc - File descriptor.

start - Optional start pointer. Null means read from the beginning.

fileIO - fileIO associated with file descriptor

segmentHeader - read segment header from fileIO

Returns:

Initialized file read header.

Throws:

IgniteCheckedException - If initialized failed due to another unexpected error.

initReadHandle

protected AbstractWalRecordsIterator.AbstractReadFileHandle initReadHandle(@NotNull
                                                                           @NotNull AbstractWalRecordsIterator.AbstractFileDescriptor desc,
                                                                           @Nullable
                                                                           @Nullable WALPointer start)
                                                                    throws IgniteCheckedException,
                                                                           FileNotFoundException

Assumes file descriptor will be opened in this method. The caller of this method must be responsible for closing opened file descriptor File descriptor will be closed ONLY in case of error occurred.

Parameters:

desc - File descriptor.

start - Optional start pointer. Null means read from the beginning

Returns:

Initialized file read header.

Throws:

FileNotFoundException - If segment file is missing.

IgniteCheckedException - If initialized failed due to another unexpected error.

createReadFileHandle

protected abstract AbstractWalRecordsIterator.AbstractReadFileHandle createReadFileHandle(SegmentIO fileIO,
                                                                                          RecordSerializer ser,
                                                                                          FileInput in)