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 neighborsSize, 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(Field<CFE> field)	Get an empty immutable cache, cast to the correct type.
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.
Stream<T>	getNeighbors(FieldAbsoluteDate<KK> central)	Get the entries surrounding a central date.
int	getNeighborsSize()	Get the fixed size of the lists returned by FieldTimeStampedCache.getNeighbors(FieldAbsoluteDate).
String	toString()

Methods inherited from class java.lang.Object

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

Constructor Detail

ImmutableFieldTimeStampedCache

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

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

Parameters:

neighborsSize - the size of the list returned from 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 neighborsSize.

Throws:

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

Method Detail

emptyCache

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

Get an empty immutable cache, cast to the correct type.

Type Parameters:

TS - the type of data

CFE - the type of the calculus field element

Parameters:

field - field to which the elements belong

Returns:

an empty ImmutableTimeStampedCache.

getNeighbors

public Stream<T> getNeighbors(FieldAbsoluteDate<KK> central)

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

Returns:

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

getNeighborsSize

public int getNeighborsSize()

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

Specified by:

getNeighborsSize 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