Class HistogramLogWriter
- java.lang.Object
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- org.HdrHistogram.HistogramLogWriter
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public class HistogramLogWriter extends java.lang.Object
A histogram log writer.A Histogram logs are used to capture full fidelity, per-time-interval histograms of a recorded value.
For example, a histogram log can be used to capture high fidelity reaction-time logs for some measured system or subsystem component. Such a log would capture a full reaction time histogram for each logged interval, and could be used to later reconstruct a full HdrHistogram of the measured reaction time behavior for any arbitrary time range within the log, by adding [only] the relevant interval histograms.
This log writer will produce histogram logs that adhere to the histogram log format (see {
HistogramLogReader
for log format details). Optional comments, start time, legend, and format version can be logged.The log writer will use the
By convention, it is typical for the logging application to use a comment to indicate the logging application at the head of the log, followed by the log format version, a start time, and a legend (in that order).
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Field Summary
Fields Modifier and Type Field Description private long
baseTime
private java.util.regex.Matcher
containsDelimeterMatcher
private static java.util.regex.Pattern
containsDelimeterPattern
private static java.lang.String
HISTOGRAM_LOG_FORMAT_VERSION
private java.io.PrintStream
log
private java.nio.ByteBuffer
targetBuffer
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Constructor Summary
Constructors Constructor Description HistogramLogWriter(java.io.File outputFile)
Constructs a new HistogramLogWriter that will write into the specified file.HistogramLogWriter(java.io.OutputStream outputStream)
Constructs a new HistogramLogWriter that will write into the specified output stream.HistogramLogWriter(java.io.PrintStream printStream)
Constructs a new HistogramLogWriter that will write into the specified print stream.HistogramLogWriter(java.lang.String outputFileName)
Constructs a new HistogramLogWriter around a newly created file with the specified file name.
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description void
close()
Closes the file or output stream for this log writer.long
getBaseTime()
return the current base time offset (seesetBaseTime(long)
).void
outputBaseTime(long baseTimeMsec)
Log a base time in the log.void
outputComment(java.lang.String comment)
Log a comment to the log.void
outputIntervalHistogram(double startTimeStampSec, double endTimeStampSec, EncodableHistogram histogram)
Output an interval histogram, with the given timestamp information, and the [optional] tag associated with the histogram.void
outputIntervalHistogram(double startTimeStampSec, double endTimeStampSec, EncodableHistogram histogram, double maxValueUnitRatio)
Output an interval histogram, with the given timestamp information and the [optional] tag associated with the histogram, using a configurable maxValueUnitRatio.void
outputIntervalHistogram(EncodableHistogram histogram)
Output an interval histogram, using the start/end timestamp indicated in the histogram, and the [optional] tag associated with the histogram.void
outputLegend()
Output a legend line to the log.void
outputLogFormatVersion()
Output a log format version to the log.void
outputStartTime(long startTimeMsec)
Log a start time in the log.void
setBaseTime(long baseTimeMsec)
Set a base time to subtract from supplied histogram start/end timestamps when logging based on histogram timestamps.
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Field Detail
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HISTOGRAM_LOG_FORMAT_VERSION
private static final java.lang.String HISTOGRAM_LOG_FORMAT_VERSION
- See Also:
- Constant Field Values
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containsDelimeterPattern
private static java.util.regex.Pattern containsDelimeterPattern
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containsDelimeterMatcher
private java.util.regex.Matcher containsDelimeterMatcher
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log
private final java.io.PrintStream log
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targetBuffer
private java.nio.ByteBuffer targetBuffer
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baseTime
private long baseTime
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Constructor Detail
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HistogramLogWriter
public HistogramLogWriter(java.lang.String outputFileName) throws java.io.FileNotFoundException
Constructs a new HistogramLogWriter around a newly created file with the specified file name.- Parameters:
outputFileName
- The name of the file to create- Throws:
java.io.FileNotFoundException
- when unable to open outputFileName
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HistogramLogWriter
public HistogramLogWriter(java.io.File outputFile) throws java.io.FileNotFoundException
Constructs a new HistogramLogWriter that will write into the specified file.- Parameters:
outputFile
- The File to write to- Throws:
java.io.FileNotFoundException
- when unable to open outputFile
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HistogramLogWriter
public HistogramLogWriter(java.io.OutputStream outputStream)
Constructs a new HistogramLogWriter that will write into the specified output stream.- Parameters:
outputStream
- The OutputStream to write to
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HistogramLogWriter
public HistogramLogWriter(java.io.PrintStream printStream)
Constructs a new HistogramLogWriter that will write into the specified print stream.- Parameters:
printStream
- The PrintStream to write to
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Method Detail
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close
public void close()
Closes the file or output stream for this log writer.
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outputIntervalHistogram
public void outputIntervalHistogram(double startTimeStampSec, double endTimeStampSec, EncodableHistogram histogram, double maxValueUnitRatio)
Output an interval histogram, with the given timestamp information and the [optional] tag associated with the histogram, using a configurable maxValueUnitRatio. (note that the specified timestamp information will be used, and the timestamp information in the actual histogram will be ignored). The max value reported with the interval line will be scaled by the given maxValueUnitRatio.- Parameters:
startTimeStampSec
- The start timestamp to log with the interval histogram, in seconds.endTimeStampSec
- The end timestamp to log with the interval histogram, in seconds.histogram
- The interval histogram to log.maxValueUnitRatio
- The ratio by which to divide the histogram's max value when reporting on it.
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outputIntervalHistogram
public void outputIntervalHistogram(double startTimeStampSec, double endTimeStampSec, EncodableHistogram histogram)
Output an interval histogram, with the given timestamp information, and the [optional] tag associated with the histogram. (note that the specified timestamp information will be used, and the timestamp information in the actual histogram will be ignored). The max value in the histogram will be reported scaled down by a default maxValueUnitRatio of 1,000,000 (which is the msec : nsec ratio). Caller should use the direct form specifying maxValueUnitRatio some other ratio is needed for the max value output.- Parameters:
startTimeStampSec
- The start timestamp to log with the interval histogram, in seconds.endTimeStampSec
- The end timestamp to log with the interval histogram, in seconds.histogram
- The interval histogram to log.
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outputIntervalHistogram
public void outputIntervalHistogram(EncodableHistogram histogram)
Output an interval histogram, using the start/end timestamp indicated in the histogram, and the [optional] tag associated with the histogram. The histogram start and end timestamps are assumed to be in msec units. Logging will be in seconds, realtive by a base time (if set viasetBaseTime(long)
). The default base time is 0.By covention, histogram start/end time are generally stamped with absolute times in msec since the epoch. For logging with absolute time stamps, the base time would remain zero. For logging with relative time stamps (time since a start point), the base time should be set with
setBaseTime(long)
.The max value in the histogram will be reported scaled down by a default maxValueUnitRatio of 1,000,000 (which is the msec : nsec ratio). Caller should use the direct form specifying maxValueUnitRatio if some other ratio is needed for the max value output.
- Parameters:
histogram
- The interval histogram to log.
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outputStartTime
public void outputStartTime(long startTimeMsec)
Log a start time in the log.- Parameters:
startTimeMsec
- time (in milliseconds) since the absolute start time (the epoch)
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outputBaseTime
public void outputBaseTime(long baseTimeMsec)
Log a base time in the log.- Parameters:
baseTimeMsec
- time (in milliseconds) since the absolute start time (the epoch)
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outputComment
public void outputComment(java.lang.String comment)
Log a comment to the log. Comments will be preceded with with the '#' character.- Parameters:
comment
- the comment string.
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outputLegend
public void outputLegend()
Output a legend line to the log.
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outputLogFormatVersion
public void outputLogFormatVersion()
Output a log format version to the log.
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setBaseTime
public void setBaseTime(long baseTimeMsec)
Set a base time to subtract from supplied histogram start/end timestamps when logging based on histogram timestamps. Base time is expected to be in msec since the epoch, as histogram start/end times are typically stamped with absolute times in msec since the epoch.- Parameters:
baseTimeMsec
- base time to calculate timestamp deltas from
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getBaseTime
public long getBaseTime()
return the current base time offset (seesetBaseTime(long)
).- Returns:
- the current base time
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