Package org.eclipse.e4.core.di

Interface IInjector

public interface IInjector

An injector is used to inject data from the object supplier into a domain object. The injection will try to find fields and methods in the user objects that correspond to the names of the services present in the context. Subsequent changes to the context after injection will cause the affected items to be re-injected into the object. Thus the object will remain synchronized with the context once it has been injected.

Matching of methods and fields to be injected is performed using the annotations defined in packages jakarta.inject and org.eclipse.e4.core.services.annotations.

The injection of values is generally done as a number of calls. User objects that want to finalize the injected data (for instance, to perform calculations based on multiple injected values) can place such calculations in a method with the PostConstruct annotation.

When injecting values, all fields are injected prior to injection of methods. When values are removed from the context or the context is disposed, injection of null values occurs in the reverse order: methods and then fields. As a result, injection methods can safely make use of injected field values. The order in which methods are injected is undefined, so injection methods should not rely on other injection methods having been run already. Methods and field on superclasses are injected before methods in fields on the subclasses.

When supplier is disposed, the injector will attempt to notify all injected objects by calling methods with the PreDestroy annotation.

Since:

1.7

Restriction:

This interface is not intended to be implemented by clients.

Restriction:

This interface is not intended to be extended by clients.

Field Summary

Fields

Modifier and Type	Field	Description
static final Object	NOT_A_VALUE	Methods may return this to indicate that the requested object was not found wherever null can be a valid return value.

Method Summary

Modifier and Type	Method	Description
IBinding	addBinding(Class<?> clazz)	Creates a binding for the specified class and adds it to the injector.
IBinding	addBinding(IBinding binding)	Adds binding to the injector.
void	inject(Object object, PrimaryObjectSupplier objectSupplier)	Injects data from the supplier into a domain object.
void	inject(Object object, PrimaryObjectSupplier objectSupplier, PrimaryObjectSupplier staticSupplier)	Injects data from the supplier into a domain object.
Object	invoke(Object object, Class<? extends Annotation> qualifier, Object defaultValue, PrimaryObjectSupplier objectSupplier)	Call the annotated method on an object, injecting the parameters from the supplier.
Object	invoke(Object object, Class<? extends Annotation> qualifier, Object defaultValue, PrimaryObjectSupplier objectSupplier, PrimaryObjectSupplier localSupplier)	Call the annotated method on an object, injecting the parameters from the suppliers.
Object	invoke(Object object, Class<? extends Annotation> qualifier, PrimaryObjectSupplier objectSupplier)	Call the annotated method on an object, injecting the parameters from the supplier.
<T> T	make(Class<T> clazz, PrimaryObjectSupplier objectSupplier)	Obtain an instance of the specified class and inject it with the data from the supplier.
<T> T	make(Class<T> clazz, PrimaryObjectSupplier objectSupplier, PrimaryObjectSupplier staticSupplier)	Obtain an instance of the specified class and inject it with the data from the supplier.
void	setDefaultSupplier(PrimaryObjectSupplier objectSupplier)	Specifies object supplier to inject internally created objects, such as extended object suppliers.
void	uninject(Object object, PrimaryObjectSupplier objectSupplier)	Un-injects the supplier from the object.

Field Details

NOT_A_VALUE

static final Object NOT_A_VALUE

Methods may return this to indicate that the requested object was not found wherever null can be a valid return value.

Method Details

inject

void inject(Object object,
 PrimaryObjectSupplier objectSupplier)
     throws InjectionException

Injects data from the supplier into a domain object. See the class comment for details on the injection algorithm that is used.

Parameters:

object - the object to perform injection on

objectSupplier - primary object supplier for the injection

Throws:

InjectionException - if an exception occurred while performing this operation

inject

void inject(Object object,
 PrimaryObjectSupplier objectSupplier,
 PrimaryObjectSupplier staticSupplier)
     throws InjectionException

Injects data from the supplier into a domain object. See the class comment for details on the injection algorithm that is used.

If values for the same key present in both the object supplier and the static supplier, the values from the static supplier are injected. Injected values from the static supplier are not tracked and no links between the static supplier and the object are established.

Parameters:

object - the object to perform injection on

objectSupplier - primary object supplier for the injection

staticSupplier - additional object supplier for the injection, changes in injected values are not tracked

Throws:

InjectionException - if an exception occurred while performing this operation

Since:

1.7

uninject

void uninject(Object object,
 PrimaryObjectSupplier objectSupplier)
       throws InjectionException

Un-injects the supplier from the object.

Parameters:

object - the domain object previously injected with the supplier's data

objectSupplier - primary object supplier for the injection

Throws:

InjectionException - if an exception occurred while performing this operation

invoke

Object invoke(Object object,
 Class<? extends Annotation> qualifier,
 PrimaryObjectSupplier objectSupplier)
       throws InjectionException

Call the annotated method on an object, injecting the parameters from the supplier.

If no matching method is found on the class, an InjectionException will be thrown.

Parameters:

object - the object on which the method should be called

qualifier - the annotation tagging method to be called

objectSupplier - primary object supplier

Returns:

the return value of the method call, might be null

Throws:

InjectionException - if an exception occurred while performing this operation

invoke

Object invoke(Object object,
 Class<? extends Annotation> qualifier,
 Object defaultValue,
 PrimaryObjectSupplier objectSupplier)
       throws InjectionException

Call the annotated method on an object, injecting the parameters from the supplier.

If no matching method is found on the class, the defaultValue will be returned.

Parameters:

object - the object on which the method should be called

qualifier - the annotation tagging method to be called

defaultValue - a value to be returned if the method cannot be called, might be null

objectSupplier - primary object supplier

Returns:

the return value of the method call, might be null

Throws:

InjectionException - if an exception occurred while performing this operation

invoke

Object invoke(Object object,
 Class<? extends Annotation> qualifier,
 Object defaultValue,
 PrimaryObjectSupplier objectSupplier,
 PrimaryObjectSupplier localSupplier)
       throws InjectionException

Call the annotated method on an object, injecting the parameters from the suppliers.

If no matching method is found on the class, the defaultValue will be returned.

Parameters:

object - the object on which the method should be called

qualifier - the annotation tagging method to be called

defaultValue - a value to be returned if the method cannot be called, might be null

objectSupplier - primary object supplier

localSupplier - primary object supplier, values override objectSupplier

Returns:

the return value of the method call, might be null

Throws:

InjectionException - if an exception occurred while performing this operation

make

<T> T make(Class<T> clazz,
 PrimaryObjectSupplier objectSupplier)
    throws InjectionException

Obtain an instance of the specified class and inject it with the data from the supplier.

Type Parameters:

T - the type of the object to be created

Parameters:

clazz - the class to be instantiated

objectSupplier - primary object supplier for the injection

Returns:

an instance of the specified class

Throws:

InjectionException - if an exception occurred while performing this operation

See Also:

• Scope
• Singleton

make

<T> T make(Class<T> clazz,
 PrimaryObjectSupplier objectSupplier,
 PrimaryObjectSupplier staticSupplier)
    throws InjectionException

Obtain an instance of the specified class and inject it with the data from the supplier.

If values for the same key present in both the object supplier and the static supplier, the values from the static supplier are injected. Injected values from the static supplier are not tracked and no links between the static supplier and the object are established.

Type Parameters:

T - the type of the object to be created

Parameters:

clazz - the class to be instantiated

objectSupplier - primary object supplier for the injection

staticSupplier - additional object supplier for the injection, changes in injected values are not tracked

Returns:

an instance of the specified class

Throws:

InjectionException - if an exception occurred while performing this operation

See Also:

• Scope
• Singleton

addBinding

IBinding addBinding(Class<?> clazz)

Creates a binding for the specified class and adds it to the injector.

Parameters:

clazz - the class that the injector should be aware of

Returns:

binding for the specified class

addBinding

IBinding addBinding(IBinding binding)

Adds binding to the injector.

Parameters:

binding - the binding to add to the injector

Returns:

the binding added to the injector

setDefaultSupplier

void setDefaultSupplier(PrimaryObjectSupplier objectSupplier)

Specifies object supplier to inject internally created objects, such as extended object suppliers.

Parameters:

objectSupplier - the object supplier used to inject objects implicitly created by this injector

Since:

1.2