domino.java.capsule

Class DynamicVariable<T>

java.lang.Object

domino.java.capsule.DynamicVariable<T>

public class DynamicVariable<T>
extends java.lang.Object

`DynamicVariable` provides a binding mechanism where the current value is found through dynamic scope, but where access to the variable itself is resolved through static scope.

The current value can be retrieved with the value() method. New values should be pushed using the withValue(Object, F0) method. Values pushed via withValue(Object, F0) only stay valid while the withValue(Object, F0)'s second argument, a parameterless closure, executes. When the second argument finishes, the variable reverts to the previous value.

 someDynamicVariable.withValue(newValue, () -> {
 // ... code called in here that calls value ...
 // ... will be given back the newValue ...
 })

 

Each thread gets its own stack of bindings. When a new thread is created, the `DynamicVariable` gets a copy of the stack of bindings from the parent thread, and from then on the bindings for the new thread are independent of those for the original thread.

This class was ported from Scala 2.11 (`scala.util.DynamicVariable`), which as orginally written by Lex Spoon.

Constructor Summary

Constructors

Constructor and Description
DynamicVariable(T init)

Method Summary

Modifier and Type	Method and Description
void	setValue(T newVal) Change the currently bound value, discarding the old value.
java.lang.String	toString()
T	value() Retrieve the current value.
<S> S	withValue(T newVal, de.tototec.utils.functional.F0<S> thunk) Set the value of the variable while executing the specified thunk.

Methods inherited from class java.lang.Object

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

Constructor Detail

DynamicVariable

public DynamicVariable(T init)

Method Detail

value

public T value()

Retrieve the current value.

withValue

public <S> S withValue(T newVal,
                       de.tototec.utils.functional.F0<S> thunk)

Set the value of the variable while executing the specified thunk.

Parameters:

newval - The value to which to set the variable.

thunk - The code to evaluate under the new setting.

setValue

public void setValue(T newVal)

Change the currently bound value, discarding the old value. Usually withValue(Object, F0) gives better semantics.

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object