Package com.identityworksllc.iiq.common

Class VersionedThreadLocal<T>

java.lang.Object

com.identityworksllc.iiq.common.VersionedThreadLocal<T>

Type Parameters:

T - the type of the value held in this ThreadLocal

All Implemented Interfaces:

Supplier<T>

public class VersionedThreadLocal<T>
extends Object
implements Supplier<T>

A thread-local container that is associated with the plugin cache version.

If a new plugin is installed, the version increments, and the entire ThreadLocal will be replaced. This means that running processes relying on plugin-provided classes can retrieve new versions of those objects.

Your Supplier code should always assume that the plugin cache has been refreshed since the last invocation and never cache plugin objects.

The object type T, of course, cannot be the actual implementation in the plugin classloader, as that class will have become invalid when the plugin cache was reset. The type T should be either a JDK class or a custom interface implemented at the webapp layer.

Constructor Summary

Constructors

Constructor	Description
VersionedThreadLocal()	Creates a new VersionedThreadLocal with the default initial value of null.

Method Summary

Modifier and Type	Method	Description
T	compute(Supplier<? extends T> supplier)	Computes the value for this ThreadLocal using the given supplier.
T	get()	Returns the current value in this ThreadLocal.
void	set(T value)	Sets the value in this ThreadLocal.
static <U> VersionedThreadLocal<U>	withInitial(Supplier<? extends U> supplier)	Creates a new VersionedThreadLocal with the given initial value.

Methods inherited from class java.lang.Object

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

Constructor Detail

VersionedThreadLocal

public VersionedThreadLocal()

Creates a new VersionedThreadLocal with the default initial value of null.

Method Detail

withInitial

public static <U> VersionedThreadLocal<U> withInitial(Supplier<? extends U> supplier)

Creates a new VersionedThreadLocal with the given initial value.

Type Parameters:

U - the type of the value held in this ThreadLocal

Parameters:

supplier - the initial value supplier

Returns:

a new VersionedThreadLocal

See Also:

ThreadLocal.withInitial(Supplier)

compute

public T compute(Supplier<? extends T> supplier)

Computes the value for this ThreadLocal using the given supplier.

If the value is already set, it will be returned. Otherwise, the supplier will be called to compute the value and set it in this ThreadLocal.

Parameters:

supplier - the supplier to compute the value

Returns:

the current or computed value

get

public T get()

Returns the current value in this ThreadLocal.

If the version has changed, a new ThreadLocal will be created and the value returned from that.

Specified by:

get in interface Supplier<T>

Returns:

the current value in this ThreadLocal

See Also:

ThreadLocal.get()

set

public void set(T value)

Sets the value in this ThreadLocal.

If the version has changed, a new ThreadLocal will be created and the value set in that.

Parameters:

value - the new value to set

See Also:

ThreadLocal.set(Object)