Package org.orekit.utils

Class ImmutableFieldTimeStampedCache<T extends FieldTimeStamped<KK>,KK extends CalculusFieldElement<KK>>

java.lang.Object

org.orekit.utils.ImmutableFieldTimeStampedCache<T,KK>

Type Parameters:

T - the type of data

KK - the type the field element

All Implemented Interfaces:

FieldTimeStampedCache<T,KK>

public class ImmutableFieldTimeStampedCache<T extends FieldTimeStamped<KK>,KK extends CalculusFieldElement<KK>>
extends Object
implements FieldTimeStampedCache<T,KK>

A cache of TimeStamped data that provides concurrency through immutability. This strategy is suitable when all the cached data is stored in memory. (For example, UTCScale) This class then provides convenient methods for accessing the data.

Author:

Evan Ward, Vincent Cucchietti

Constructor Summary

Constructors

Constructor	Description
ImmutableFieldTimeStampedCache(int maxNeighborsSize, Collection<? extends T> data)	Create a new cache with the given neighbors size and data.

Method Summary

Modifier and Type	Method	Description
static <TS extends FieldTimeStamped<CFE>, CFE extends CalculusFieldElement<CFE>> ImmutableFieldTimeStampedCache<TS,CFE>	emptyCache()	Get an empty immutable cache.
List<T>	getAll()	Get all the data in this cache.
T	getEarliest()	Get the earliest entry in this cache.
T	getLatest()	Get the latest entry in this cache.
int	getMaxNeighborsSize()	Get the fixed size of the lists returned by FieldTimeStampedCache.getNeighbors(FieldAbsoluteDate).
Stream<T>	getNeighbors(FieldAbsoluteDate<KK> central, int n)	Get the entries surrounding a central date.
String	toString()

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.orekit.utils.FieldTimeStampedCache

getNeighbors

Constructor Details

ImmutableFieldTimeStampedCache

public ImmutableFieldTimeStampedCache(int maxNeighborsSize,
 Collection<? extends T> data)

Create a new cache with the given neighbors size and data.

Parameters:

maxNeighborsSize - the maximum size of the list returned from FieldTimeStampedCache.getNeighbors(FieldAbsoluteDate). Must be less than or equal to data.size().

data - the backing data for this cache. The list will be copied to ensure immutability. To guarantee immutability the entries in data must be immutable themselves. There must be more data than maxNeighborsSize.

Throws:

IllegalArgumentException - if maxNeighborsSize > data.size() or if maxNeighborsSize is negative

Method Details

emptyCache

public static <TS extends FieldTimeStamped<CFE>,
CFE extends CalculusFieldElement<CFE>>
ImmutableFieldTimeStampedCache<TS,CFE> emptyCache()

Get an empty immutable cache.

Type Parameters:

TS - the type of data

CFE - the type of the calculus field element

Returns:

an empty ImmutableTimeStampedCache.

Since:

12.1

getNeighbors

public Stream<T> getNeighbors(FieldAbsoluteDate<KK> central,
 int n)

Get the entries surrounding a central date.

If the central date is well within covered range, the returned array will be balanced with half the points before central date and half the points after it (depending on n parity, of course). If the central date is near the boundary, then the returned array will be unbalanced and will contain only the n earliest (or latest) entries. A typical example of the later case is leap seconds cache, since the number of leap seconds cannot be arbitrarily increased.

This method is safe for multiple threads to execute concurrently.

Specified by:

getNeighbors in interface FieldTimeStampedCache<T extends FieldTimeStamped<KK>,KK extends CalculusFieldElement<KK>>

Parameters:

central - central date

n - number of neighbors (cannot exceed FieldTimeStampedCache.getMaxNeighborsSize())

Returns:

list of cached entries surrounding the specified date. The size of the list is guaranteed to be FieldTimeStampedCache.getMaxNeighborsSize().

getMaxNeighborsSize

public int getMaxNeighborsSize()

Get the fixed size of the lists returned by FieldTimeStampedCache.getNeighbors(FieldAbsoluteDate).

Specified by:

getMaxNeighborsSize in interface FieldTimeStampedCache<T extends FieldTimeStamped<KK>,KK extends CalculusFieldElement<KK>>

Returns:

size of the list

getEarliest

public T getEarliest()

Get the earliest entry in this cache.

Specified by:

getEarliest in interface FieldTimeStampedCache<T extends FieldTimeStamped<KK>,KK extends CalculusFieldElement<KK>>

Returns:

earliest cached entry

getLatest

public T getLatest()

Get the latest entry in this cache.

Specified by:

getLatest in interface FieldTimeStampedCache<T extends FieldTimeStamped<KK>,KK extends CalculusFieldElement<KK>>

Returns:

latest cached entry

getAll

public List<T> getAll()

Get all the data in this cache.

Returns:

a sorted collection of all data passed in the constructor.

toString

public String toString()

Overrides:

toString in class Object