Module org.yamcs.core

Package org.yamcs.parameter

Class LastValueCache

java.lang.Object

org.yamcs.parameter.LastValueCache

public class LastValueCache
extends Object

Cache for the last known value of each parameter.

Can also stored a number of n values for certain parameters (required by algorithms and match criterias)

it uses a readwrite lock to synchronize access from multiple threads.

Constructor Summary

Constructors

Constructor	Description
LastValueCache()
LastValueCache(Collection<ParameterValue> constants)

Method Summary

Modifier and Type	Method	Description
void	add(ParameterValue pv)	Adds a new value.
void	addAll(Collection<ParameterValue> newValues)	Add all parameters to the cache
void	enableBuffering(Parameter param, int capacity)	Configure the parameter cache to remember at least capacity values for the parameter.
ParameterValue	getValue(Parameter param)	Returns the latest known value for p or null if there is none.
ParameterValue	getValue(Parameter param, int n)	return the n'th newest value or null if no such a value exist. n has to be smaller or equal with 0.
Collection<ParameterValue>	getValues()	returns all the values from the cache
int	size()

Methods inherited from class java.lang.Object

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

Constructor Details

LastValueCache

public LastValueCache()

LastValueCache

public LastValueCache(Collection<ParameterValue> constants)

Method Details

getValue

public ParameterValue getValue(Parameter param)

Returns the latest known value for p or null if there is none.

Parameters:

param -

Returns:

getValue

public ParameterValue getValue(Parameter param,
 int n)

return the n'th newest value or null if no such a value exist. n has to be smaller or equal with 0.

If n=0 it is equivalent with getValue(Parameter)

If n<0 but buffering is not enabled for the parameter or the buffer capacity is smaller than -n+1, an IllegalStateException will be thrown

Throws:

IllegalArgumentException - if n>0 or if n<0 and the parameter is constant

IllegalStateException - if buffering is not enabled or the buffer capacity is smaller than -n+1

enableBuffering

public void enableBuffering(Parameter param,
 int capacity)

Configure the parameter cache to remember at least capacity values for the parameter.

The size has to be at least 2 (because size 1 is by default)

Throws:

IllegalArgumentException - if the capacity is smaller than 2 or the parameter is a constant.

add

public void add(ParameterValue pv)

Adds a new value. If buffering is enabled, the value is added to the buffer, otherwise it replaces the old value (if any)

Parameters:

pv -

addAll

public void addAll(Collection<ParameterValue> newValues)

Add all parameters to the cache

Parameters:

newValues -

size

public int size()

getValues

public Collection<ParameterValue> getValues()

returns all the values from the cache

Returns: