Package com.tuladb.currency

Class CurrencyScales

java.lang.Object

com.tuladb.currency.CurrencyScales

public final class CurrencyScales
extends Object

Per-currency scales from the engine's currency registry.

The first use of a numeric asks the engine (MSG_CURRENCY_GET); a found scale is cached forever, because the engine refuses to change a registered currency's scale. A miss is cached for NOT_REGISTERED_TTL_NANOS (2 s): a currency registered elsewhere is picked up within that window, and an unregistered one does not cost a round trip per call; until then it is a CurrencyNotRegisteredException, never a guessed scale. A currency created through createCurrency(com.tuladb.Models.CurrencyInstance) is cached at once. Safe to share between threads.

 CurrencyScales scales = new CurrencyScales(client::getCurrency, client::createCurrency);
 long minor = scales.toMinor(124, "800.00");   // 80000
 String text = scales.format(124, minor);      // "800.00"
 

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static interface	CurrencyScales.CurrencyCreator	The create half of the registry: LedgerClient::createCurrency, ...
static interface	CurrencyScales.CurrencyLookup	Where registry entries come from: LedgerClient::getCurrency, SmartLedgerClient::getCurrency, a pooled lookup, ...

Field Summary

Fields

Modifier and Type	Field	Description
static final long	NOT_REGISTERED_TTL_NANOS	How long a miss is remembered (the shared rule: 2 s).

Constructor Summary

Constructors

Constructor	Description
CurrencyScales(CurrencyScales.CurrencyLookup lookup)
CurrencyScales(CurrencyScales.CurrencyLookup lookup, CurrencyScales.CurrencyCreator creator)	With creator, createCurrency(com.tuladb.Models.CurrencyInstance) registers and caches at once.
CurrencyScales(CurrencyScales.CurrencyLookup lookup, CurrencyScales.CurrencyCreator creator, long missTtlNanos, LongSupplier clockNanos)	Explicit miss TTL and clock (nanoseconds), for tests.

Method Summary

Modifier and Type	Method	Description
Models.CurrencyInstance	createCurrency(Models.CurrencyInstance request)	Register through the creator given at construction and cache the registered scale at once.
void	forget(int numeric)	Drop one cached scale or miss.
String	format(int numeric, long minor)
int	remember(int numeric, int scale)	Record a scale learned elsewhere (e.g. a create reply); clears a remembered miss.
int	scale(int numeric)	The registered scale of numeric, asking the engine on first use.
long	toMinor(int numeric, String text)
long	toMinor(int numeric, BigDecimal value)

Methods inherited from class java.lang.Object

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

Field Details

NOT_REGISTERED_TTL_NANOS

public static final long NOT_REGISTERED_TTL_NANOS

How long a miss is remembered (the shared rule: 2 s).

See Also:

• Constant Field Values

Constructor Details

CurrencyScales

public CurrencyScales(CurrencyScales.CurrencyLookup lookup)

CurrencyScales

public CurrencyScales(CurrencyScales.CurrencyLookup lookup,
 CurrencyScales.CurrencyCreator creator)

With creator, createCurrency(com.tuladb.Models.CurrencyInstance) registers and caches at once.

CurrencyScales

public CurrencyScales(CurrencyScales.CurrencyLookup lookup,
 CurrencyScales.CurrencyCreator creator,
 long missTtlNanos,
 LongSupplier clockNanos)

Explicit miss TTL and clock (nanoseconds), for tests.

Method Details

scale

public int scale(int numeric)
          throws IOException

The registered scale of numeric, asking the engine on first use.

Throws:

CurrencyNotRegisteredException - the engine has no such currency

IOException - the registry could not be asked

remember

public int remember(int numeric,
 int scale)

Record a scale learned elsewhere (e.g. a create reply); clears a remembered miss.

createCurrency

public Models.CurrencyInstance createCurrency(Models.CurrencyInstance request)
                                       throws IOException

Register through the creator given at construction and cache the registered scale at once.

Throws:

IOException

toMinor

public long toMinor(int numeric,
 String text)
             throws IOException

Throws:

IOException

toMinor

public long toMinor(int numeric,
 BigDecimal value)
             throws IOException

Throws:

IOException

format

public String format(int numeric,
 long minor)
              throws IOException

Throws:

IOException

forget

public void forget(int numeric)

Drop one cached scale or miss. Only needed when the cache outlives the engine it was filled from.