Module org.fuin.cqrs4j

Package org.fuin.cqrs4j

Class Cqrs4JUtils

java.lang.Object

org.fuin.cqrs4j.Cqrs4JUtils

public final class Cqrs4JUtils
extends Object

Provides some helper methods.

Field Summary

Fields

Modifier and Type	Field	Description
static final List<Class<?>>	JAXB_CLASSES	Classes used for JAX-B serialization.
static final String	PARAM_ENTITY_PATH_NOT_EQUAL_CMD_ENTITY_PATH	Result code for verifyParamEntityIdPathEqualsCmdEntityIdPath(AggregateCommand, EntityId...) failures.
static final String	PRECONDITION_VIOLATED	Some constraints were violated.
static final String	SHORT_ID_PREFIX	Prefix for unique short identifiers.

Method Summary

Modifier and Type	Method	Description
static void	runLocked(@NotNull Semaphore lock, @NotNull Runnable code)	Waits until a lock is available and executes the code after it was acquired.
static void	tryLocked(@NotNull Semaphore lock, @NotNull Runnable code)	Tries to acquire a lock and runs the code.
static <ID extends org.fuin.ddd4j.ddd.EntityId> Result<?>	verifyParamEntityIdPathEqualsCmdEntityIdPath(@NotNull AggregateCommand<?,?> cmd, @NotNull ID... entityIds)	Verifies that an aggregate identifier from a parameter is equal to the aggregate identifier from the command.
static Result<?>	verifyPrecondition(@NotNull jakarta.validation.Validator validator, @NotNull Object obj)	Verifies a precondition.

Methods inherited from class java.lang.Object

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

Field Details

JAXB_CLASSES

public static final List<Class<?>> JAXB_CLASSES

Classes used for JAX-B serialization.

PRECONDITION_VIOLATED

public static final String PRECONDITION_VIOLATED

Some constraints were violated.

See Also:

• Constant Field Values

PARAM_ENTITY_PATH_NOT_EQUAL_CMD_ENTITY_PATH

public static final String PARAM_ENTITY_PATH_NOT_EQUAL_CMD_ENTITY_PATH

Result code for verifyParamEntityIdPathEqualsCmdEntityIdPath(AggregateCommand, EntityId...) failures.

See Also:

• Constant Field Values

SHORT_ID_PREFIX

public static final String SHORT_ID_PREFIX

Prefix for unique short identifiers.

See Also:

• Constant Field Values

Method Details

tryLocked

public static void tryLocked(@NotNull
 @NotNull Semaphore lock,
 @NotNull
 @NotNull Runnable code)

Tries to acquire a lock and runs the code. If no lock can be acquired, the method terminates immediately without executing anything.

Parameters:

lock - Semaphore to use.

code - Code to run.

runLocked

public static void runLocked(@NotNull
 @NotNull Semaphore lock,
 @NotNull
 @NotNull Runnable code)

Waits until a lock is available and executes the code after it was acquired.

Parameters:

lock - Semaphore to use.

code - Code to run.

verifyPrecondition

public static Result<?> verifyPrecondition(@NotNull
 @NotNull jakarta.validation.Validator validator,
 @NotNull
 @NotNull Object obj)

Verifies a precondition. In case of constraint violations, the error is logged and an error result is returned.

Parameters:

validator - Validator to use.

obj - Object to validate. A null value is considered to be an error.

Returns:

Error result or null if validation was successful.

verifyParamEntityIdPathEqualsCmdEntityIdPath

@SafeVarargs
public static <ID extends org.fuin.ddd4j.ddd.EntityId>
Result<?> verifyParamEntityIdPathEqualsCmdEntityIdPath(@NotNull
 @NotNull AggregateCommand<?,?> cmd,
 @NotNull
 @NotNull ID... entityIds)

Verifies that an aggregate identifier from a parameter is equal to the aggregate identifier from the command. This is helpful, if for example the URL contains the name of the aggregate, followed by an aggregate identifier.
Example: POST /customer/f832a5a4-dd80-49df-856a-7274de82cd6b/create
The ID from the URL must match the aggregate ID that is passed via the command in the body.

Type Parameters:

ID - Type of the aggregate root identifier.

Parameters:

cmd - Command that has the entity identifier path to compare with.

entityIds - Identifiers to compare with.

Returns:

Error result or null if validation was successful.