Package org.occurrent.application.composition.command

Class ListCommandComposition

java.lang.Object

org.occurrent.application.composition.command.ListCommandComposition

public class ListCommandComposition
extends Object

Compose several "list commands" (Function<List<T>, List<T>>) into one by leveraging function composition. Commands will be executed in left-to-right order, for example:

 Function<List<T>, List<T>> domainFunction1 = ..
 Function<List<T>, List<T>> domainFunction2 = ..

 applicationService.execute("streamid", composeCommands(domainFunction1, domainFunction2));
 

In this example, domainFunction1 will execute before domainFunction2 and the events returned from domainFunction2 will be appended as input to domainFunction2. All events will then be written atomically to an event store.

Note that in most cases the domain function will not have the form Function<List<T>, List<T>>. You can then use PartialFunctionApplication to create partially applied functions that you can then compose.

Constructor Summary

Constructors

Constructor	Description
ListCommandComposition()

Method Summary

Modifier and Type	Method	Description
static <T> Function<List<T>,List<T>>	composeCommands(Function<List<T>,List<T>> firstCommand, Function<List<T>,List<T>> secondCommand, Function<List<T>,List<T>>... additionalCommands)	Compose the supplied commands into a single function.
static <T> Function<List<T>,List<T>>	composeCommands(List<Function<List<T>,List<T>>> commands)	Compose the supplied list of commands into a single function.
static <T> Function<List<T>,List<T>>	composeCommands(Stream<Function<List<T>,List<T>>> commands)	Compose the supplied stream of commands into a single function.

Methods inherited from class java.lang.Object

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

Constructor Details

ListCommandComposition

public ListCommandComposition()

Method Details

composeCommands

@SafeVarargs
public static <T> Function<List<T>,List<T>> composeCommands(Function<List<T>,List<T>> firstCommand,
 Function<List<T>,List<T>> secondCommand,
 Function<List<T>,List<T>>... additionalCommands)

Compose the supplied commands into a single function.

Type Parameters:

T - The domain event type

Parameters:

firstCommand - The first command to compose

secondCommand - The second command to compose

additionalCommands - Additional commands to compose

Returns:

A single function that is a composition of all supplied commands

composeCommands

public static <T> Function<List<T>,List<T>> composeCommands(List<Function<List<T>,List<T>>> commands)

Compose the supplied list of commands into a single function.

Type Parameters:

T - The domain event type

Parameters:

commands - The commands to compose

Returns:

A single function that is a composition of all supplied commands

composeCommands

public static <T> Function<List<T>,List<T>> composeCommands(Stream<Function<List<T>,List<T>>> commands)

Compose the supplied stream of commands into a single function.

Type Parameters:

T - The domain event type

Parameters:

commands - The commands to compose

Returns:

A single function that is a composition of all supplied commands