org.osgi.service.component.annotations

Annotation Type Component

@Retention(value=CLASS)
 @Target(value=TYPE)
 @RequireServiceComponentRuntime
public @interface Component

Identify the annotated class as a Service Component.

The annotated class is the implementation class of the Component.

This annotation is not processed at runtime by Service Component Runtime. It must be processed by tools and used to add a Component Description to the bundle.

See Also:

"The component element of a Component Description."

Field Summary

Fields

Modifier and Type	Fields and Description
static java.lang.String	NAME Special string representing the name of this Component.

Optional Element Summary

Optional Elements

Modifier and Type	Optional Element and Description
java.lang.String[]	configurationPid The configuration PIDs for the configuration of this Component.
ConfigurationPolicy	configurationPolicy The configuration policy of this Component.
boolean	enabled Declares whether this Component is enabled when the bundle declaring it is started.
java.lang.String	factory The factory identifier of this Component.
java.lang.String[]	factoryProperties Factory property entries for this Factory Component.
java.lang.String[]	factoryProperty Factory properties for this Factory Component.
boolean	immediate Declares whether this Component must be immediately activated upon becoming satisfied or whether activation should be delayed.
java.lang.String	name The name of this Component.
java.lang.String[]	properties Property entries for this Component.
java.lang.String[]	property Properties for this Component.
Reference[]	reference The lookup strategy references of this Component.
ServiceScope	scope The service scope for the service of this Component.
java.lang.Class<?>[]	service The types under which to register this Component as a service.
boolean	servicefactory Deprecated. Since 1.3. Replaced by scope().
java.lang.String	xmlns The XML name space of the Component Description for this Component.

Field Detail

NAME

public static final java.lang.String NAME

Special string representing the name of this Component.

This string can be used in configurationPid() to specify the name of the component as a configuration PID. For example:

 @Component(configurationPid={"com.acme.system", Component.NAME})
 

Tools creating a Component Description from this annotation must replace the special string with the actual name of this Component.

Since:

1.3

Element Detail

name

public abstract java.lang.String name

The name of this Component.

If not specified, the name of this Component is the fully qualified type name of the class being annotated.

See Also:

"The name attribute of the component element of a Component Description."

Default:

""

service

public abstract java.lang.Class<?>[] service

The types under which to register this Component as a service.

If no service should be registered, the empty value {} must be specified.

If not specified, the service types for this Component are all the directly implemented interfaces of the class being annotated.

See Also:

"The service element of a Component Description."

Default:

{}

factory

public abstract java.lang.String factory

The factory identifier of this Component. Specifying a factory identifier makes this Component a Factory Component.

If not specified, the default is that this Component is not a Factory Component.

See Also:

"The factory attribute of the component element of a Component Description."

Default:

""

servicefactory

public abstract boolean servicefactory

Deprecated. Since 1.3. Replaced by scope().

Declares whether this Component uses the OSGi ServiceFactory concept and each bundle using this Component's service will receive a different component instance.

This element is ignored when the scope() element does not have the default value. If true, this Component uses bundle service scope. If false or not specified, this Component uses singleton service scope. If the factory() element is specified or the immediate() element is specified with true, this element can only be specified with false.

See Also:

"The scope attribute of the service element of a Component Description."

Default:

false

enabled

public abstract boolean enabled

Declares whether this Component is enabled when the bundle declaring it is started.

If true or not specified, this Component is enabled. If false, this Component is disabled.

See Also:

"The enabled attribute of the component element of a Component Description."

Default:

true

immediate

public abstract boolean immediate

Declares whether this Component must be immediately activated upon becoming satisfied or whether activation should be delayed.

If true, this Component must be immediately activated upon becoming satisfied. If false, activation of this Component is delayed. If this property is specified, its value must be false if the factory() property is also specified or must be true if the service() property is specified with an empty value.

If not specified, the default is false if the factory() property is specified or the service() property is not specified or specified with a non-empty value and true otherwise.

See Also:

"The immediate attribute of the component element of a Component Description."

Default:

false

property

public abstract java.lang.String[] property

Properties for this Component.

Each property string is specified as "name=value". The type of the property value can be specified in the name as name:type=value. The type must be one of the property types supported by the type attribute of the property element of a Component Description.

To specify a property with multiple values, use multiple name, value pairs. For example, {"foo=bar", "foo=baz"}.

See Also:

"The property element of a Component Description."

Default:

{}

properties

public abstract java.lang.String[] properties

Property entries for this Component.

Specifies the name of an entry in the bundle whose contents conform to a standard Java Properties File. The entry is read and processed to obtain the properties and their values.

See Also:

"The properties element of a Component Description."

Default:

{}

xmlns

public abstract java.lang.String xmlns

The XML name space of the Component Description for this Component.

If not specified, the XML name space of the Component Description for this Component should be the lowest Declarative Services XML name space which supports all the specification features used by this Component.

See Also:

"The XML name space specified for a Component Description."

Default:

""

configurationPolicy

public abstract ConfigurationPolicy configurationPolicy

The configuration policy of this Component.

Controls whether component configurations must be satisfied depending on the presence of a corresponding Configuration object in the OSGi Configuration Admin service. A corresponding configuration is a Configuration object where the PID equals the name of the component.

If not specified, the configuration policy is based upon whether the component is also annotated with the Meta Type Designate annotation.

• Not annotated with Designate - The configuration policy is OPTIONAL.
• Annotated with Designate(factory=false) - The configuration policy is OPTIONAL.
• Annotated with Designate(factory=true) - The configuration policy is REQUIRE.

Since:

1.1

See Also:

"The configuration-policy attribute of the component element of a Component Description."

Default:

org.osgi.service.component.annotations.ConfigurationPolicy.OPTIONAL

configurationPid

public abstract java.lang.String[] configurationPid

The configuration PIDs for the configuration of this Component.

Each value specifies a configuration PID for this Component.

If no value is specified, the name of this Component is used as the configuration PID of this Component.

A special string ("$") can be used to specify the name of the component as a configuration PID. The NAME constant holds this special string. For example:

 @Component(configurationPid={"com.acme.system", Component.NAME})
 

Tools creating a Component Description from this annotation must replace the special string with the actual name of this Component.

Since:

1.2

See Also:

"The configuration-pid attribute of the component element of a Component Description."

Default:

"$"

scope

public abstract ServiceScope scope

The service scope for the service of this Component.

If not specified (and the deprecated servicefactory() element is not specified), the singleton service scope is used. If the factory() element is specified or the immediate() element is specified with true, this element can only be specified with the singleton service scope.

Since:

1.3

See Also:

"The scope attribute of the service element of a Component Description."

Default:

org.osgi.service.component.annotations.ServiceScope.DEFAULT

reference

public abstract Reference[] reference

The lookup strategy references of this Component.

To access references using the lookup strategy, Reference annotations are specified naming the reference and declaring the type of the referenced service. The referenced service can be accessed using one of the locateService methods of ComponentContext.

To access references using method injection, bind methods are annotated with Reference. To access references using field injection, fields are annotated with Reference. To access references using constructor injection, constructor parameters are annotated with Reference.

Since:

1.3

See Also:

"The reference element of a Component Description."

Default:

{}

factoryProperty

public abstract java.lang.String[] factoryProperty

Factory properties for this Factory Component.

Each factory property string is specified as "name=value". The type of the factory property value can be specified in the name as name:type=value. The type must be one of the factory property types supported by the type attribute of the factory-property element of a Component Description.

To specify a factory property with multiple values, use multiple name, value pairs. For example, {"foo=bar", "foo=baz"}.

If specified, the factory() element must also be specified to indicate the component is a Factory Component.

Since:

1.4

See Also:

"The factory-property element of a Component Description."

Default:

{}

factoryProperties

public abstract java.lang.String[] factoryProperties

Factory property entries for this Factory Component.

Specifies the name of an entry in the bundle whose contents conform to a standard Java Properties File. The entry is read and processed to obtain the factory properties and their values.

If specified, the factory() element must also be specified to indicate the component is a Factory Component.

Since:

1.4

See Also:

"The factory-properties element of a Component Description."

Default:

{}