Package com.vaadin.flow.di

Class LookupInitializer

java.lang.Object

com.vaadin.flow.di.LookupInitializer

All Implemented Interfaces:

AbstractLookupInitializer

public class LookupInitializer
extends Object
implements AbstractLookupInitializer

Default implementation of AbstractLookupInitializer.

Author:

Vaadin Ltd

See Also:

• AbstractLookupInitializer

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
protected static class	LookupInitializer.AppShellPredicateImpl	Default implementation of AppShellPredicate.
protected static class	LookupInitializer.LookupImpl	Default implementation of Lookup.
protected static class	LookupInitializer.ResourceProviderImpl	Default implementation of ResourceProvider.

Field Summary

Fields

Modifier and Type	Field	Description
protected static final String	ONE_IMPL_REQUIRED
protected static final String	SEVERAL_IMPLS
protected static final String	SPI

Constructor Summary

Constructors

Constructor	Description
LookupInitializer()

Method Summary

Modifier and Type	Method	Description
protected Lookup	createLookup(VaadinContext context, Map<Class<?>,Collection<Class<?>>> services)	Creates a lookup based on provided services.
protected <T> void	ensureService(Map<Class<?>,Collection<Class<?>>> services, Class<T> serviceType, Class<? extends T> serviceImpl)	Ensures that provided services contain implementation for serviceType SPI.
static Set<Class<?>>	getDefaultImplementations()	Returns the default implementation classes included.
void	initialize(VaadinContext context, Map<Class<?>,Collection<Class<?>>> services, VaadinApplicationInitializationBootstrap bootstrap)	Creates a new Lookup instance, initializes it and passes it to the provided bootstrap.
protected <T> T	instantiate(Class<T> serviceClass, Class<?> implementation)	Instantiates service implementation type with the given serviceClass .

Methods inherited from class java.lang.Object

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

Field Details

SPI

protected static final String SPI

See Also:

• Constant Field Values

ONE_IMPL_REQUIRED

protected static final String ONE_IMPL_REQUIRED

See Also:

• Constant Field Values

SEVERAL_IMPLS

protected static final String SEVERAL_IMPLS

See Also:

• Constant Field Values

Constructor Details

LookupInitializer

public LookupInitializer()

Method Details

initialize

public void initialize(VaadinContext context,
 Map<Class<?>,Collection<Class<?>>> services,
 VaadinApplicationInitializationBootstrap bootstrap)
                throws jakarta.servlet.ServletException

Description copied from interface: AbstractLookupInitializer

Creates a new Lookup instance, initializes it and passes it to the provided bootstrap.

The method should creates a new initialized Lookup instance. In some cases it's not possible to create the instance right away when the method is called. To be able to support this usecase the method contract doesn't require to return the Lookup instance. Instead the created instance should be passed to the provided bootstrap consumer once the instance is created and completely initialized. The bootstrap will start the application initialization which otherwise is postponed until a Lookup becomes available.

The implementation must use the provided bootstrap to pass the Lookup instance otherwise the web application based on this LookupInitializer will never be bootstrapped.

The provided services map contains service implementations found in application classpath using @HandlesTypes annotation declared for LookupServletContainerInitializer.

Specified by:

initialize in interface AbstractLookupInitializer

Parameters:

context - a Vaadin context to run initialization for

services - the map of internal services with their implementations found in the application classpath

bootstrap - the web application bootstrap

Throws:

jakarta.servlet.ServletException - if initialization failed

createLookup

protected Lookup createLookup(VaadinContext context,
 Map<Class<?>,Collection<Class<?>>> services)

Creates a lookup based on provided services.

Parameters:

context - a Vaadin context to create a lookup for

services - the service objects mapped to the service type to create a lookup

Returns:

the lookup instance created with provided services

ensureService

protected <T> void ensureService(Map<Class<?>,Collection<Class<?>>> services,
 Class<T> serviceType,
 Class<? extends T> serviceImpl)

Ensures that provided services contain implementation for serviceType SPI.

The default serviceImpl implementation will be set as the service into services if there is no other services available.

Type Parameters:

T - the service type

Parameters:

services - map of internal services

serviceType - SPI type

serviceImpl - the default SPI implementation

instantiate

protected <T> T instantiate(Class<T> serviceClass,
 Class<?> implementation)

Instantiates service implementation type with the given serviceClass .

Type Parameters:

T - service type

Parameters:

serviceClass - service class

implementation - service implementation class

Returns:

an instantiated service implementation object

getDefaultImplementations

public static Set<Class<?>> getDefaultImplementations()

Returns the default implementation classes included.

This method is public only for internal purposes.

Returns:

a set of classes