io.flamingock.internal.common.core.template

Class ChangeTemplateManager

java.lang.Object

io.flamingock.internal.common.core.template.ChangeTemplateManager

public final class ChangeTemplateManager
extends java.lang.Object

Manages the discovery, registration, and retrieval of ChangeTemplate implementations.

This class serves two primary purposes in different contexts:

1. GraalVM Build-time Context - The getTemplates() method is called by the GraalVM RegistrationFeature to discover all available templates. For each template, the feature registers both the template class itself and all classes returned by ReflectionMetadataProvider.getReflectiveClasses() for reflection in native images.
2. Runtime Context - The loadTemplates() method is called during Flamingock initialization to populate the internal registry with all available templates for use during execution.

Templates are discovered through Java's ServiceLoader mechanism from two sources:

• Direct implementations of ChangeTemplate registered via SPI
• Templates provided by ChangeTemplateFactory implementations registered via SPI

Thread Safety Note: This class is not thread-safe during initialization. The loadTemplates() method modifies static state and is intended to be called only once during application startup from a single thread. After initialization, the template registry is effectively read-only and can be safely accessed concurrently.

Method Summary

Modifier and Type	Method and Description
static void	addTemplate(java.lang.String templateName, java.lang.Class<? extends io.flamingock.api.template.ChangeTemplate<?,?,?>> templateClass) Adds a template to the internal registry for testing purposes.
static java.util.Optional<java.lang.Class<? extends io.flamingock.api.template.ChangeTemplate<?,?,?>>>	getTemplate(java.lang.String templateName) Retrieves a template class by name from the internal registry.
static java.util.Collection<io.flamingock.api.template.ChangeTemplate<?,?,?>>	getTemplates() Discovers and returns all available templates from the classpath.
static void	loadTemplates() Loads and registers all available templates from the classpath into the internal registry.

Methods inherited from class java.lang.Object

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

Method Detail

loadTemplates

public static void loadTemplates()

Loads and registers all available templates from the classpath into the internal registry.

This method is intended to be called once during Flamingock runtime initialization. It discovers all templates via getTemplates() and registers them in the internal registry, indexed by their simple class name.

This method is not thread-safe and should be called from a single thread during application startup before any template lookups are performed.

getTemplates

public static java.util.Collection<io.flamingock.api.template.ChangeTemplate<?,?,?>> getTemplates()

Discovers and returns all available templates from the classpath.

This method is used in two contexts:

• By the GraalVM RegistrationFeature during build time to discover templates that need reflection registration for native image generation
• By the loadTemplates() method during runtime initialization to populate the internal template registry

Templates are discovered from two sources:

1. Direct implementations of ChangeTemplate registered via SPI
2. Templates provided by ChangeTemplateFactory implementations registered via SPI

This method creates new instances of templates each time it's called and does not modify any internal state.

Returns:

A collection of all discovered template instances

addTemplate

@TestOnly
public static void addTemplate(java.lang.String templateName,
                                         java.lang.Class<? extends io.flamingock.api.template.ChangeTemplate<?,?,?>> templateClass)

Adds a template to the internal registry for testing purposes.

This method is intended for use in test environments only to register mock or test templates. It directly modifies the internal template registry and is not thread-safe.

Parameters:

templateName - The name to register the template under (typically the simple class name)

templateClass - The template class to register

getTemplate

public static java.util.Optional<java.lang.Class<? extends io.flamingock.api.template.ChangeTemplate<?,?,?>>> getTemplate(java.lang.String templateName)

Retrieves a template class by name from the internal registry.

This method is used during runtime to look up template classes by their simple name. It returns an Optional that will be empty if no template with the specified name has been registered.

This method is thread-safe after initialization (after loadTemplates() has been called).

Parameters:

templateName - The simple class name of the template to retrieve

Returns:

An Optional containing the template class if found, or empty if not found