org.orekit.utils

Class ImmutableTimeStampedCache<T extends TimeStamped>

java.lang.Object

org.orekit.utils.ImmutableTimeStampedCache<T>

Type Parameters:

T - the type of data

All Implemented Interfaces:

TimeStampedCache<T>

public class ImmutableTimeStampedCache<T extends TimeStamped>
extends Object
implements TimeStampedCache<T>

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

Author:

Evan Ward

Constructor Summary

Constructors

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

Method Summary

Methods

Modifier and Type	Method and Description
static <TS extends TimeStamped> ImmutableTimeStampedCache<TS>	emptyCache() Get an empty immutable cache, cast to the correct type.
List<T>	getAll() Get all of the data in this cache.
T	getEarliest() Get the earliest entry in this cache.
T	getLatest() Get the latest entry in this cache.
List<T>	getNeighbors(AbsoluteDate central) Get the entries surrounding a central date.
int	getNeighborsSize() Get the fixed size of the lists returned by TimeStampedCache.getNeighbors(AbsoluteDate).
String	toString()

Methods inherited from class java.lang.Object

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

Constructor Detail

ImmutableTimeStampedCache

public ImmutableTimeStampedCache(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(AbsoluteDate). 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 neightborsSize > data.size() or if neighborsSize is negative

Method Detail

getNeighbors

public List<T> getNeighbors(AbsoluteDate central)
                                         throws TimeStampedCacheException

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 TimeStampedCache<T extends TimeStamped>

Parameters:

central - central date

Returns:

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

Throws:

TimeStampedCacheException - if central is outside the range of data this cache is capable of providing.

getNeighborsSize

public int getNeighborsSize()

Description copied from interface: TimeStampedCache

Get the fixed size of the lists returned by TimeStampedCache.getNeighbors(AbsoluteDate).

Specified by:

getNeighborsSize in interface TimeStampedCache<T extends TimeStamped>

Returns:

size of the list

getEarliest

public T getEarliest()

Description copied from interface: TimeStampedCache

Get the earliest entry in this cache.

Specified by:

getEarliest in interface TimeStampedCache<T extends TimeStamped>

Returns:

earliest cached entry

getLatest

public T getLatest()

Description copied from interface: TimeStampedCache

Get the latest entry in this cache.

Specified by:

getLatest in interface TimeStampedCache<T extends TimeStamped>

Returns:

latest cached entry

getAll

public List<T> getAll()

Get all of 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

emptyCache

public static final <TS extends TimeStamped> ImmutableTimeStampedCache<TS> emptyCache()

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

Type Parameters:

TS - the type of data

Returns:

an empty ImmutableTimeStampedCache.