com.serotonin.mango.rt.dataImage

Class PointValueCache

java.lang.Object

com.serotonin.mango.rt.dataImage.PointValueCache

public class PointValueCache
extends java.lang.Object

This class maintains an ordered list of the most recent values for a data point. It will mirror values in the database, but provide a much faster lookup for a limited number of values. Because there is not a significant performance problem for time-based lookups, they are not handled here, but rather are still handled by the database.

Author:

Matthew Lohbihler

Field Summary

Fields

Modifier and Type	Field and Description
private java.util.List<PointValueTime>	cache IMPORTANT: The list object should never be written to!
private PointValueDao	dao
private int	dataPointId
private int	defaultSize
private static org.apache.commons.logging.Log	LOG
private int	maxSize

Constructor Summary

Constructors

Constructor and Description
PointValueCache(int dataPointId, int defaultSize)

Method Summary

Modifier and Type	Method and Description
java.util.List<PointValueTime>	getCacheContents() Never manipulate the contents of this list!
PointValueTime	getLatestPointValue()
java.util.List<PointValueTime>	getLatestPointValues(int limit)
(package private) void	logPointValueAsync(PointValueTime pointValue, SetPointSource source) Saves the given value to the database without adding it to the cache.
private void	refreshCache(int size)
void	reset()
void	savePointValue(PointValueTime pvt, SetPointSource source, boolean logValue, boolean async)

Methods inherited from class java.lang.Object

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

Field Detail

LOG

private static final org.apache.commons.logging.Log LOG

dataPointId

private final int dataPointId

defaultSize

private final int defaultSize

dao

private final PointValueDao dao

cache

private java.util.List<PointValueTime> cache

IMPORTANT: The list object should never be written to! The implementation here is for performance. Never call methods like add() or remove() on the cache object. Further, since the cache object can be replaced from time to time, always use a local copy of the variable for read purposes.

maxSize

private int maxSize

Constructor Detail

PointValueCache

public PointValueCache(int dataPointId,
                       int defaultSize)

Method Detail

savePointValue

public void savePointValue(PointValueTime pvt,
                           SetPointSource source,
                           boolean logValue,
                           boolean async)

logPointValueAsync

void logPointValueAsync(PointValueTime pointValue,
                        SetPointSource source)

Saves the given value to the database without adding it to the cache.

getLatestPointValue

public PointValueTime getLatestPointValue()

getLatestPointValues

public java.util.List<PointValueTime> getLatestPointValues(int limit)

refreshCache

private void refreshCache(int size)

getCacheContents

public java.util.List<PointValueTime> getCacheContents()

Never manipulate the contents of this list!

reset

public void reset()