org.apache.tamaya.inject.api

Class BaseDynamicValue<T>

java.lang.Object

org.apache.tamaya.inject.api.BaseDynamicValue<T>

Type Parameters:

T - The type of the value.

All Implemented Interfaces:

Serializable, DynamicValue<T>

public abstract class BaseDynamicValue<T>
extends Object
implements DynamicValue<T>, Serializable

A accessor for a single configured value. This can be used to support values that may change during runtime, reconfigured or final. Hereby external code (could be Tamaya configuration listners or client code), can set a new value. Depending on the UpdatePolicy the new value is immedeately active or it requires an active commit by client code. Similarly an instance also can ignore all later changes to the value.

Types of this interface can be used as injection targets in injected beans or as template resiult on configuration templates.

Implementation Specification

Implementation of this interface must be

• Serializable, when also the item stored is serializable
• Thread safe

See Also:

Serialized Form

Constructor Summary

Constructors

Constructor and Description
BaseDynamicValue()

Method Summary

Methods

Modifier and Type	Method and Description
T	commitAndGet() Performs a commit, if necessary, and returns the current value.
boolean	isPresent() Return true if there is a value present, otherwise false.
T	orElse(T other) Return the value if present, otherwise return other.
T	orElseGet(ConfiguredItemSupplier<? extends T> other) Return the value if present, otherwise invoke other and return the result of that invocation.
<X extends Throwable> T	orElseThrow(ConfiguredItemSupplier<? extends X> exceptionSupplier) Return the contained value, if present, otherwise throw an exception to be created by the provided supplier.

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.apache.tamaya.inject.api.DynamicValue

addListener, commit, evaluateValue, get, getNewValue, getUpdatePolicy, removeListener, setUpdatePolicy, updateValue

Constructor Detail

BaseDynamicValue

public BaseDynamicValue()

Method Detail

commitAndGet

public T commitAndGet()

Performs a commit, if necessary, and returns the current value.

Specified by:

commitAndGet in interface DynamicValue<T>

Returns:

the non-null value held by this DynamicValue

Throws:

org.apache.tamaya.ConfigException - if there is no value present

See Also:

DynamicValue.isPresent()

isPresent

public boolean isPresent()

Return true if there is a value present, otherwise false.

Specified by:

isPresent in interface DynamicValue<T>

Returns:

true if there is a value present, otherwise false

orElse

public T orElse(T other)

Return the value if present, otherwise return other.

Specified by:

orElse in interface DynamicValue<T>

Parameters:

other - the value to be returned if there is no value present, may be null

Returns:

the value, if present, otherwise other

orElseGet

public T orElseGet(ConfiguredItemSupplier<? extends T> other)

Return the value if present, otherwise invoke other and return the result of that invocation.

Specified by:

orElseGet in interface DynamicValue<T>

Parameters:

other - a ConfiguredItemSupplier whose result is returned if no value is present

Returns:

the value if present otherwise the result of other.get()

Throws:

NullPointerException - if value is not present and other is null

orElseThrow

public <X extends Throwable> T orElseThrow(ConfiguredItemSupplier<? extends X> exceptionSupplier)
              throws X extends Throwable

Return the contained value, if present, otherwise throw an exception to be created by the provided supplier.

NOTE A method reference to the exception constructor with an empty argument list can be used as the supplier. For example, IllegalStateException::new

Specified by:

orElseThrow in interface DynamicValue<T>

Type Parameters:

X - Type of the exception to be thrown

Parameters:

exceptionSupplier - The supplier which will return the exception to be thrown

Returns:

the present value

Throws:

X - if there is no value present

NullPointerException - if no value is present and exceptionSupplier is null

X extends Throwable