org.yamcs.parameter

Class ParameterCacheImpl

java.lang.Object

org.yamcs.parameter.ParameterCacheImpl

All Implemented Interfaces:

ParameterCache

public class ParameterCacheImpl
extends Object
implements ParameterCache

Used by the ParameterRequestManager to cache last values of parameters. The cache will contain the parameters for a predefined time period but can exceed that period if space is available in the CacheEntry. A CacheEntry also has a maximum size to prevent it accumulating parameters ad infinitum (e.g. if there are bogus parameters with the timestamp never changing) We keep delivery consisting of lists of parameter values together such that if two parameters have been acquired in the same delivery, they will be given from the same delivery to the clients. if cacheAll is enabled, all parameters will be cached as they are received. if cacheAll is disabled: - a parameter will be put on the list to cache only if somebody has requested it. - obviously first time when the parameter is requested, no value will be returned. - however this will greatly reduce the cache size since only a few parameters are monitored in the displays

Author:

nm

Constructor Summary

Constructors

Constructor and Description
ParameterCacheImpl(ParameterCacheConfig cacheConfig)

Method Summary

Modifier and Type	Method and Description
void	clear() Remove all the parameters from the cache
List<ParameterValue>	getAllValues(Parameter p) Returns all values from the cache for the parameter or null if there is no value cached The parameter are returned in descending order (newest parameter is returned first)
List<ParameterValue>	getAllValues(Parameter p, long start, long stop) Same as above but return all values that have the generation time in the (start, stop] interval
ParameterValue	getLastValue(Parameter p) Returns last cached value for parameter or null if there is no value in the cache
List<ParameterValue>	getValues(List<Parameter> plist) Returns cached value for parameter or an empty list if there is no value in the cache
void	update(Collection<ParameterValue> pvs) update the parameters in the cache

Methods inherited from class java.lang.Object

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

Constructor Detail

ParameterCacheImpl

public ParameterCacheImpl(ParameterCacheConfig cacheConfig)

Method Detail

update

public void update(Collection<ParameterValue> pvs)

Description copied from interface: ParameterCache

update the parameters in the cache

Specified by:

update in interface ParameterCache

Parameters:

pvs - - parameter value list

getValues

public List<ParameterValue> getValues(List<Parameter> plist)

Description copied from interface: ParameterCache

Returns cached value for parameter or an empty list if there is no value in the cache

Specified by:

getValues in interface ParameterCache

Returns:

getLastValue

public ParameterValue getLastValue(Parameter p)

Description copied from interface: ParameterCache

Returns last cached value for parameter or null if there is no value in the cache

Specified by:

getLastValue in interface ParameterCache

Parameters:

p - - parameter for which the last value is returned

Returns:

getAllValues

public List<ParameterValue> getAllValues(Parameter p)

Description copied from interface: ParameterCache

Returns all values from the cache for the parameter or null if there is no value cached The parameter are returned in descending order (newest parameter is returned first)

Specified by:

getAllValues in interface ParameterCache

Parameters:

p - - parameter for which all values are returned

Returns:

all values from the cache for the parameter or null if there is no value cached

getAllValues

public List<ParameterValue> getAllValues(Parameter p,
                                         long start,
                                         long stop)

Description copied from interface: ParameterCache

Same as above but return all values that have the generation time in the (start, stop] interval

Specified by:

getAllValues in interface ParameterCache

Returns:

clear

public void clear()

Description copied from interface: ParameterCache

Remove all the parameters from the cache

Specified by:

clear in interface ParameterCache