org.openmdx.kernel.log
Interface LogEntityReader

All Known Implementing Classes:

LogFileParser

public interface LogEntityReader

Defines the interface for log entity readers

Method Summary

int	readBinary(long startPos, byte[] buffer) Reads from a start position a given number of bytes from the log file.
long	readLogEvents(long startPos, int maxEvents, long maxProcessingTime, LogEventFilter filter, ArrayList eventList) Parses the log entity for log events.
long	readLogEvents(long startPos, int maxEvents, long maxProcessingTime, LogEventFilter filter, ObjectOutputStream target)
long	size() Returns the size of the log entity in bytes

Method Detail

readLogEvents

long readLogEvents(long startPos,
                   int maxEvents,
                   long maxProcessingTime,
                   LogEventFilter filter,
                   ArrayList eventList)
                   throws IOException,
                          UnsupportedOperationException

Parses the log entity for log events. Returns at most events log events. If the start position is >0 the parser seeks to next starting log event.

If the file position is a positive number the reading starts from the given file position. If the given file position is a negative number it is used as offset from the end of the file.

Be prepared that the requested number of events can be limited.

The parser returns if either the end of the file is reached, the max number of events is parsed or the max processing time is exceeded.

Parameters:

startPos - The start position where the parsing starts

maxEvents - The max number of events to be processed

maxProcessingTime - The max processing time in milliseconds. A value of 0 means no time limit.

filter - A log event filter

eventList - The event list to be filled with the parsed

Returns:

The file position after reading all the events

Throws:

IOException - Thrown if file does not exist or cannot be read

UnsupportedOperationException - if readig log events is not supported on the currently used log entity

readLogEvents

long readLogEvents(long startPos,
                   int maxEvents,
                   long maxProcessingTime,
                   LogEventFilter filter,
                   ObjectOutputStream target)
                   throws IOException,
                          UnsupportedOperationException

Throws:

IOException

UnsupportedOperationException

readBinary

int readBinary(long startPos,
               byte[] buffer)
               throws IOException,
                      UnsupportedOperationException

Reads from a start position a given number of bytes from the log file.

Note that not all log entities may support binary reading.

Parameters:

startPos - The start position where the parsing starts

buffer - The allocated buffer to receive the file data

Returns:

The number of bytes read. 0 indicates EOF

Throws:

IOException - Thrown if file does not exist or cannot be read

UnsupportedOperationException - if binary read is not supported on the currently used log entity

size

long size()
          throws IOException,
                 UnsupportedOperationException

Returns the size of the log entity in bytes

Returns:

The log entity size

Throws:

IOException - Thrown if file does not exist or cannot be read

UnsupportedOperationException - if the entity size is not supported on the currently used log entity