org.osgi.service.component.annotations.Component Maven / Gradle / Ivy
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/*
* Copyright (c) OSGi Alliance (2011, 2015). All Rights Reserved.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.osgi.service.component.annotations;
import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;
/**
* 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 "The component element of a Component Description."
* @author $Id: d44af93dcb1a5e97ef594074d075c86f68f3b3b7 $
*/
@Retention(RetentionPolicy.CLASS)
@Target(ElementType.TYPE)
public @interface Component {
/**
* 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 "The name attribute of the component element of a Component Description."
*/
String name() default "";
/**
* 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 "The service element of a Component Description."
*/
Class[] service() default {};
/**
* 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 "The factory attribute of the component element of a Component Description."
*/
String factory() default "";
/**
* 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 {@link #scope()} element does not have
* the default value. If {@code true}, this Component uses
* {@link ServiceScope#BUNDLE bundle} service scope. If {@code false} or not
* specified, this Component uses {@link ServiceScope#SINGLETON singleton}
* service scope. If the {@link #factory()} element is specified or the
* {@link #immediate()} element is specified with {@code true}, this element
* can only be specified with {@code false}.
*
* @see "The scope attribute of the service element of a Component Description."
* @deprecated Since 1.3. Replaced by {@link #scope()}.
*/
boolean servicefactory() default false;
/**
* Declares whether this Component is enabled when the bundle containing it
* is started.
*
*
* If {@code true} or not specified, this Component is enabled. If
* {@code false}, this Component is disabled.
*
* @see "The enabled attribute of the component element of a Component Description."
*/
boolean enabled() default true;
/**
* Declares whether this Component must be immediately activated upon
* becoming satisfied or whether activation should be delayed.
*
*
* If {@code true}, this Component must be immediately activated upon
* becoming satisfied. If {@code false}, activation of this Component is
* delayed. If this property is specified, its value must be {@code false}
* if the {@link #factory()} property is also specified or must be
* {@code true} if the {@link #service()} property is specified with an
* empty value.
*
*
* If not specified, the default is {@code false} if the {@link #factory()}
* property is specified or the {@link #service()} property is not specified
* or specified with a non-empty value and {@code true} otherwise.
*
* @see "The immediate attribute of the component element of a Component Description."
*/
boolean immediate() default false;
/**
* Properties for this Component.
*
*
* Each property string is specified as {@code "name=value"}. The type of
* the property value can be specified in the name as
* {@code 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, {@code "foo=bar", "foo=baz"}.
*
* @see "The property element of a Component Description."
*/
String[] property() default {};
/**
* 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 "The properties element of a Component Description."
*/
String[] properties() default {};
/**
* 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 "The XML name space specified for a Component Description."
*/
String xmlns() default "";
/**
* 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
* {@link org.osgi.service.metatype.annotations.Designate Designate}
* annotation.
*
* - Not annotated with {@code Designate} - The configuration policy is
* {@link ConfigurationPolicy#OPTIONAL OPTIONAL}.
* - Annotated with {@code Designate(factory=false)} - The configuration
* policy is {@link ConfigurationPolicy#OPTIONAL OPTIONAL}.
* - Annotated with {@code Designate(factory=true)} - The configuration
* policy is {@link ConfigurationPolicy#REQUIRE REQUIRE}.
*
*
* @see "The configuration-policy attribute of the component element of a Component Description."
* @since 1.1
*/
ConfigurationPolicy configurationPolicy() default ConfigurationPolicy.OPTIONAL;
/**
* 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 ({@value #NAME}) can be used to specify the
* name of the component as a configuration PID. The {@code 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.
*
* @see "The configuration-pid attribute of the component element of a Component Description."
* @since 1.2
*/
String[] configurationPid() default NAME;
/**
* Special string representing the name of this Component.
*
*
* This string can be used in {@link #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
*/
String NAME = "$";
/**
* The service scope for the service of this Component.
*
*
* If not specified (and the deprecated {@link #servicefactory()} element is
* not specified), the {@link ServiceScope#SINGLETON singleton} service
* scope is used. If the {@link #factory()} element is specified or the
* {@link #immediate()} element is specified with {@code true}, this element
* can only be specified with the {@link ServiceScope#SINGLETON singleton}
* service scope.
*
* @see "The scope attribute of the service element of a Component Description."
* @since 1.3
*/
ServiceScope scope() default ServiceScope.DEFAULT;
/**
* The lookup strategy references of this Component.
*
*
* To access references using the lookup strategy, {@link 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 {@code locateService} methods of {@code ComponentContext}.
*
*
* To access references using the event strategy, bind methods are annotated
* with {@link Reference}. To access references using the field strategy,
* fields are annotated with {@link Reference}.
*
* @see "The reference element of a Component Description."
* @since 1.3
*/
Reference[] reference() default {};
}