io.simplesource.saga.client.dsl

Class SagaDSL

java.lang.Object

io.simplesource.saga.client.dsl.SagaDSL

public final class SagaDSL
extends Object

The saga DSL is used be the client to build a saga.

To build a saga:

1. Create a SagaBuilder with createBuilder()
2. Use the SagaBuilder to add saga actions. Each addAction() creates a SubSaga.
3. Define the dependencies between the saga actions with andThen(). Defining dependencies between actions creates subsagas consisting of multiple actions. Dependencies can be defined between these subsagas.
4. Create the saga with build(). Any SubSagas that are not dependent on each other can be executed in parallel.

For example:

     import io.simplesource.saga.client.dsl.SagaDSL;
     import static io.simplesource.saga.client.dsl.SagaDSL;

     SagaBuilder<A> sagaBuilder = SagaDSL.createBuilder();

     SubSaga<A> actionA = sagaBuilder.addAction(actionIdA, actionCommandA, undoCommandA);
     SubSaga<A> actionB = sagaBuilder.addAction(actionIdB, actionB, undoActionB);
     SubSaga<A> actionC = sagaBuilder.addAction(actionIdC, actionC, undoActionC);

     inParallel(actionA, actionB).andThen(actionC);

     Result<SagaError, Saga<A>> sagaBuildResult = sagaBuilder.build();
 

The andThen operator is associative. This means that the following are equivalent:

     a.andThen(b.andThen(c))

and

     a.andThen(b).andThen(c)

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	SagaDSL.SagaBuilder<A> A SagaBuilder is used to add actions by creating a subsaga consisting of a single action, and to build the saga once the definition steps are complete.
static class	SagaDSL.SubSaga<A> A Subsaga is a subset of a saga consisting of one or more action, with dependencies defined between them.

Constructor Summary

Constructors

Constructor and Description
SagaDSL()

Method Summary

Modifier and Type	Method and Description
static <A> SagaDSL.SagaBuilder<A>	createBuilder() Creates a SagaBuilder
static <A> SagaDSL.SubSaga<A>	inParallel(Collection<SagaDSL.SubSaga<A>> subSagas) Creates a subsagas consisting of a collection of subsagas executing in parallel.
static <A> SagaDSL.SubSaga<A>	inParallel(SagaDSL.SubSaga<A> subSaga, SagaDSL.SubSaga<A>... subSagas) Creates a subsagas consisting of one or more subsagas executing in parallel.
static <A> SagaDSL.SubSaga<A>	inSeries(Iterable<SagaDSL.SubSaga<A>> subSagas) Creates a subsagas consisting of an ordered collection of subsagas executing in series.
static <A> SagaDSL.SubSaga<A>	inSeries(SagaDSL.SubSaga<A> subSaga, SagaDSL.SubSaga<A>... subSagas) Creates a subsagas consisting of one or more subsagas executing in series.

Methods inherited from class java.lang.Object

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

Constructor Detail

SagaDSL

public SagaDSL()

Method Detail

createBuilder

public static <A> SagaDSL.SagaBuilder<A> createBuilder()

Creates a SagaBuilder

Type Parameters:

A - a representation of an action command that is shared across all actions in the saga. This is typically a generic type, such as Json, or if using Avro serialization, SpecificRecord or GenericRecord

Returns:

the saga builder

inParallel

public static <A> SagaDSL.SubSaga<A> inParallel(SagaDSL.SubSaga<A> subSaga,
                                                SagaDSL.SubSaga<A>... subSagas)

Creates a subsagas consisting of one or more subsagas executing in parallel. In parallel means they have the same dependencies, the same subsagas depend on them, but they are not dependent on each other.

Type Parameters:

A - a representation of an action command that is shared across all actions in the saga. This is typically a generic type, such as Json, or if using Avro serialization, SpecificRecord or GenericRecord

Parameters:

subSagas - a sub saga

subSagas - the sub sagas

Returns:

a sub saga consisting of all the input subsagas executed in parallel

inSeries

public static <A> SagaDSL.SubSaga<A> inSeries(SagaDSL.SubSaga<A> subSaga,
                                              SagaDSL.SubSaga<A>... subSagas)

Creates a subsagas consisting of one or more subsagas executing in series.

Type Parameters:

A - a representation of an action command that is shared across all actions in the saga. This is typically a generic type, such as Json, or if using Avro serialization, SpecificRecord or GenericRecord

Parameters:

subSagas - the sub sagas

Returns:

a sub saga consisting of all the input subsagas executed in series

inParallel

public static <A> SagaDSL.SubSaga<A> inParallel(Collection<SagaDSL.SubSaga<A>> subSagas)

Creates a subsagas consisting of a collection of subsagas executing in parallel. In parallel means they have the same dependencies, the same subsagas depend on them, but they are not dependent on each other.

Type Parameters:

A - a representation of an action command that is shared across all actions in the saga. This is typically a generic type, such as Json, or if using Avro serialization, SpecificRecord or GenericRecord

Parameters:

subSagas - A collection of subsagas

Returns:

a sub saga consisting of all the input subsagas executed in parallel

inSeries

public static <A> SagaDSL.SubSaga<A> inSeries(Iterable<SagaDSL.SubSaga<A>> subSagas)

Creates a subsagas consisting of an ordered collection of subsagas executing in series.

Type Parameters:

A - a representation of an action command that is shared across all actions in the saga. This is typically a generic type, such as Json, or if using Avro serialization, SpecificRecord or GenericRecord

Parameters:

subSagas - A collection of subsagas

Returns:

a sub saga consisting of all the input subsagas executed in series