Package dev.enola.common.context

Class Context

java.lang.Object

dev.enola.common.context.Context

All Implemented Interfaces:

AutoCloseable

public class Context
extends Object
implements AutoCloseable

Contexts 🧿 put things into perspective!

Contexts are "hierarchical", and child contexts "mask" keys in their parent.

This class is NOT thread safe. Might you want to use TLC instead?

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static interface	Context.Key<T>

Constructor Summary

Constructors

Constructor	Description
Context()
Context(Context parent)

Method Summary

Modifier and Type	Method	Description
void	close()	Close this context.
<T> T	get(Class<T> key)	Gets the instance of Class, from this or its parent context.
<K extends Enum<K> & Context.Key<T>, T> T	get(K key)	Get the value for the given key, from this or its parent context.
<T> Optional<T>	optional(Class<T> key)	Gets the instance of Class, from this or its parent context, if available.
<T, K extends Enum<K> & Context.Key<T>> Optional<T>	optional(K key)	Get the value for the given key, from this or its parent context, if available.
<T> void	push(Context.Key<T> key, T instance)
<T> Context	push(Class<T> key, T value)
<K extends Enum<K> & Context.Key<T>, T> Context	push(K key, T value)	Push, but not too hard…
String	toString()

Methods inherited from class java.lang.Object

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

Constructor Details

Context

public Context(Context parent)

Context

public Context()

Method Details

push

public <K extends Enum<K> & Context.Key<T>,
T>
Context push(K key,
 T value)

Push, but not too hard…

Parameters:

key - Key.

value - Value to associate with the key.

Returns:

this, for chaining.

Throws:

IllegalStateException - if this Context already has another value for the key.

push

public <T> void push(Context.Key<T> key,
 T instance)

push

public <T> Context push(Class<T> key,
 T value)

get

public <K extends Enum<K> & Context.Key<T>,
T> T get(K key)

Get the value for the given key, from this or its parent context.

Never null, but may throw IllegalStateException if not available.

Use optional(Enum) to check if key is available in Context.

get

public <T> T get(Class<T> key)

Gets the instance of Class, from this or its parent context.

Never null, but may throw IllegalStateException if not available.

Use optional(Class) to check if key is available in Context.

optional

public <T> Optional<T> optional(Class<T> key)

Gets the instance of Class, from this or its parent context, if available.

Use get(Class) if key must be available in Context.

optional

public <T,
K extends Enum<K> & Context.Key<T>>
Optional<T> optional(K key)

Get the value for the given key, from this or its parent context, if available.

Use get(Enum) if key must be available in Context.

toString

public String toString()

Overrides:

toString in class Object

close

public void close()

Close this context. Don't use it anymore!

Specified by:

close in interface AutoCloseable