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>>

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

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 FileIOFactory	ioFactory Factory to provide I/O interfaces for read/write operations with files
protected IgniteLogger	log Logger

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	AbstractWalRecordsIterator(IgniteLogger log, GridCacheSharedContext sharedCtx, RecordSerializer serializer, FileIOFactory ioFactory, int bufSize)

Method Summary

Methods

Modifier and Type	Method and Description
protected void	advance() Switches records iterator to the next record.
protected abstract FileWriteAheadLogManager.ReadFileHandle	advanceSegment(FileWriteAheadLogManager.ReadFileHandle curWalSegment) Switches records iterator to the next WAL segment as result of this method, new reference to segment should be returned.
protected FileWriteAheadLogManager.ReadFileHandle	closeCurrentWalSegment() Closes and returns WAL segment (if any)
protected void	handleRecordException(Exception e, FileWALPointer ptr) Handler for record deserialization exception
protected FileWriteAheadLogManager.ReadFileHandle	initReadHandle(FileWriteAheadLogManager.FileDescriptor desc, FileWALPointer start)
protected static FileWriteAheadLogManager.FileDescriptor[]	loadFileDescriptors(File walFilesDir) Scans provided folder for a WAL segment files
protected boolean	onHasNext()
protected IgniteBiTuple<WALPointer,WALRecord>	onNext()

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

checkClosed, close, hasNextX, isClosed, nextX, onClose, 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

iterator

Methods inherited from interface java.util.Iterator

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 IgniteLogger log

Logger

ioFactory

@NotNull
protected final FileIOFactory ioFactory

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

Constructor Detail

AbstractWalRecordsIterator

protected AbstractWalRecordsIterator(@NotNull
                          IgniteLogger log,
                          @NotNull
                          GridCacheSharedContext sharedCtx,
                          @NotNull
                          RecordSerializer serializer,
                          @NotNull
                          FileIOFactory ioFactory,
                          int bufSize)

Parameters:

log - Logger

sharedCtx - Shared context

serializer - Serializer of current version to read headers.

bufSize - buffer for reading records size

Method Detail

loadFileDescriptors

protected static FileWriteAheadLogManager.FileDescriptor[] loadFileDescriptors(@NotNull
                                                            File walFilesDir)
                                                                        throws IgniteCheckedException

Scans provided folder for a WAL segment files

Parameters:

walFilesDir - directory to scan

Returns:

found WAL file descriptors

Throws:

IgniteCheckedException

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.

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.

closeCurrentWalSegment

@Nullable
protected FileWriteAheadLogManager.ReadFileHandle closeCurrentWalSegment()
                                                                  throws IgniteCheckedException

Closes and returns WAL segment (if any)

Returns:

closed handle

Throws:

IgniteCheckedException - if IO failed

advanceSegment

protected abstract FileWriteAheadLogManager.ReadFileHandle advanceSegment(@Nullable
                                                     FileWriteAheadLogManager.ReadFileHandle 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

handleRecordException

protected void handleRecordException(@NotNull
                         Exception e,
                         @Nullable
                         FileWALPointer ptr)

Handler for record deserialization exception

Parameters:

e - problem from records reading

ptr - file pointer was accessed

initReadHandle

protected FileWriteAheadLogManager.ReadFileHandle initReadHandle(@NotNull
                                                     FileWriteAheadLogManager.FileDescriptor desc,
                                                     @Nullable
                                                     FileWALPointer start)
                                                          throws IgniteCheckedException,
                                                                 FileNotFoundException

Parameters:

desc - File descriptor.

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

Returns:

Initialized file handle.

Throws:

FileNotFoundException - If segment file is missing.

IgniteCheckedException - If initialized failed due to another unexpected error.