org.osgi.service.component.ComponentContext Maven / Gradle / Ivy
/*
* Copyright (c) OSGi Alliance (2004, 2017). 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;
import java.util.Dictionary;
import org.osgi.annotation.versioning.ProviderType;
import org.osgi.framework.Bundle;
import org.osgi.framework.BundleContext;
import org.osgi.framework.ServiceReference;
/**
* A Component Context object is used by a component instance to interact with
* its execution context including locating services by reference name. Each
* component instance has a unique Component Context.
*
*
* A component instance may obtain its Component Context object through its
* activate, modified, and deactivate methods.
*
* @ThreadSafe
* @author $Id: cdae000a14c3f455a96ec9028c5d437c93a32368 $
*/
@ProviderType
public interface ComponentContext {
/**
* Returns the component properties for this Component Context.
*
* @return The properties for this Component Context. The Dictionary is read
* only and cannot be modified.
*/
public Dictionary getProperties();
/**
* Returns the service object for the specified reference name.
*
*
* If the cardinality of the reference is {@code 0..n} or {@code 1..n} and
* multiple services are bound to the reference, the service with the
* highest ranking (as specified in its {@code Constants.SERVICE_RANKING}
* property) is returned. If there is a tie in ranking, the service with the
* lowest service id (as specified in its {@code Constants.SERVICE_ID}
* property); that is, the service that was registered first is returned.
*
* @param name The name of a reference as specified in a {@code reference}
* element in this component's description.
* @return A service object for the referenced service or {@code null} if
* the reference cardinality is {@code 0..1} or {@code 0..n} and no
* bound service is available.
* @throws ComponentException If Service Component Runtime catches an
* exception while activating the bound service.
*/
public S locateService(String name);
/**
* Returns the service object for the specified reference name and
* {@code ServiceReference}.
*
* @param Type of Service.
* @param name The name of a reference as specified in a {@code reference}
* element in this component's description.
* @param reference The {@code ServiceReference} to a bound service. This
* must be a {@code ServiceReference} provided to the component via
* the bind or unbind method for the specified reference name.
* @return A service object for the referenced service or {@code null} if
* the specified {@code ServiceReference} is not a bound service for
* the specified reference name.
* @throws ComponentException If Service Component Runtime catches an
* exception while activating the bound service.
*/
public S locateService(String name, ServiceReference reference);
/**
* Returns the service objects for the specified reference name.
*
* @param name The name of a reference as specified in a {@code reference}
* element in this component's description.
* @return An array of service objects for the referenced service or
* {@code null} if the reference cardinality is {@code 0..1} or
* {@code 0..n} and no bound service is available. If the reference
* cardinality is {@code 0..1} or {@code 1..1} and a bound service
* is available, the array will have exactly one element.
* @throws ComponentException If Service Component Runtime catches an
* exception while activating a bound service.
*/
public Object[] locateServices(String name);
/**
* Returns the {@code BundleContext} of the bundle which declares this
* component.
*
* @return The {@code BundleContext} of the bundle declares this component.
*/
public BundleContext getBundleContext();
/**
* If the component instance is registered as a service using the
* {@code servicescope="bundle"} or {@code servicescope="prototype"}
* attribute, then this method returns the bundle using the service provided
* by the component instance.
*
* This method will return {@code null} if:
*
* - The component instance is not a service, then no bundle can be using
* it as a service.
* - The component instance is a service but did not specify the
* {@code servicescope="bundle"} or {@code servicescope="prototype"}
* attribute, then all bundles using the service provided by the component
* instance will share the same component instance.
* - The service provided by the component instance is not currently being
* used by any bundle.
*
*
* @return The bundle using the component instance as a service or
* {@code null}.
*/
public Bundle getUsingBundle();
/**
* Returns the Component Instance object for the component instance
* associated with this Component Context.
*
* @return The Component Instance object for the component instance.
*/
public ComponentInstance getComponentInstance();
/**
* Enables the specified component name. The specified component name must
* be in the same bundle as this component.
*
*
* This method must return after changing the enabled state of the specified
* component name. Any actions that result from this, such as activating or
* deactivating a component configuration, must occur asynchronously to this
* method call.
*
* @param name The name of a component or {@code null} to indicate all
* components in the bundle.
*/
public void enableComponent(String name);
/**
* Disables the specified component name. The specified component name must
* be in the same bundle as this component.
*
*
* This method must return after changing the enabled state of the specified
* component name. Any actions that result from this, such as activating or
* deactivating a component configuration, must occur asynchronously to this
* method call.
*
* @param name The name of a component.
*/
public void disableComponent(String name);
/**
* If the component instance is registered as a service using the
* {@code service} element, then this method returns the service reference
* of the service provided by this component instance.
*
* This method will return {@code null} if the component instance is not
* registered as a service.
*
* @return The {@code ServiceReference} object for the component instance or
* {@code null} if the component instance is not registered as a
* service.
*/
public ServiceReference getServiceReference();
}