org.yamcs.parameter

Class ParameterCache

java.lang.Object

org.yamcs.parameter.ParameterCache

public class ParameterCache
extends Object

Used by the ParameterRequestManagerImpl 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
ParameterCache(ParameterCacheConfig cacheConfig)

Method Summary

Modifier and Type	Method and Description
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)
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

ParameterCache

public ParameterCache(ParameterCacheConfig cacheConfig)

Method Detail

update

public void update(Collection<ParameterValue> pvs)

update the parameters in the cache

Parameters:

pvs - - parameter value list

getValues

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

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

Parameters:

plist -

Returns:

getLastValue

public ParameterValue getLastValue(Parameter p)

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

Parameters:

p - - parameter for which the last value is returned

Returns:

getAllValues

public 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)

Parameters:

p - - parameter for which all values are returned

Returns: