Interface StreamLogScan
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- All Superinterfaces:
LogScan
- All Known Implementing Classes:
FlushedScan
,Scan
public interface StreamLogScan extends LogScan
LogScan provides methods to read a log record and get its LogInstant in an already defined scan. A logscan also needs to know how to advance to the next log record.
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Method Summary
All Methods Instance Methods Abstract Methods Modifier and Type Method Description void
close()
Close this log scan.long
getInstant()
Get the instant of the record just retrieved with getNextRecord().LogInstant
getLogInstant()
Get the LogInstant for the record just retrieved with getNextRecord().long
getLogRecordEnd()
Get the log instant that is right after the record just retrieved with getNextRecord().LogRecord
getNextRecord(ArrayInputStream input, TransactionId tranId, int groupmask)
Get the next record in the scan and place its data in the passed in array.boolean
isLogEndFuzzy()
void
resetPosition(LogInstant instant)
Reset the scan to the given LogInstant so that getNextRecord get the log record AFTER the given LogInstant.
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Method Detail
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getNextRecord
LogRecord getNextRecord(ArrayInputStream input, TransactionId tranId, int groupmask) throws StandardException, java.io.IOException
Get the next record in the scan and place its data in the passed in array. The scan is advanced to the next log record. If the input array is of insufficient size, getNextRecord must expand the array to accomodate the log record. User can optionally pass in a transaction Id and a group mask. If provided, only log record that matches the transaction Id and the group mask is returned.- Parameters:
input
- the ArrayInputStream to put the log recordtranId
- if non-null, only log record that equals tranId will be returned. If null, log records are not filtered on transaction Id.groupmask
- if non-zero, only log record whose Loggable's group value is included in the groupmask is returned. groupmask can be a bit wise OR of many Loggable groups. If zero, log records are not filtered on the Loggable's group.- Returns:
- an object that represents the log record, return null if the scan has completed.
- Throws:
StandardException
- Standard Clooudscape error policyjava.io.IOException
- Some I/O exception raised during reading the log record.
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getInstant
long getInstant()
Get the instant of the record just retrieved with getNextRecord().- Returns:
- INVALID_LOG_INSTANT if no records have been returned yet or the scan has completed.
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getLogRecordEnd
long getLogRecordEnd()
Get the log instant that is right after the record just retrieved with getNextRecord(). Only valid for a forward scan and on a successful retrieval.- Returns:
- INVALID_LOG_INSTANT if this is not a FORWARD scan or, no record have been returned yet or the scan has completed.
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isLogEndFuzzy
boolean isLogEndFuzzy()
- Returns:
- true if fuzzy log end found during forward scan, this happens if there was a partially written log records before the crash.
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getLogInstant
LogInstant getLogInstant()
Get the LogInstant for the record just retrieved with getNextRecord().- Returns:
- null if no records have been returned yet or the scan has completed.
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resetPosition
void resetPosition(LogInstant instant) throws java.io.IOException, StandardException
Reset the scan to the given LogInstant so that getNextRecord get the log record AFTER the given LogInstant.- Parameters:
instant
- the log instant to reset to- Throws:
java.io.IOException
- Some I/O exception raised when accessing the log fileStandardException
- reset to illegal position or beyond the limit of the scan.
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close
void close()
Close this log scan.
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