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/*
* Copyright (c) OSGi Alliance (2007, 2008). 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.util.tracker;
import org.osgi.framework.Bundle;
import org.osgi.framework.BundleEvent;
/**
* The BundleTrackerCustomizer interface allows a
* BundleTracker to customize the Bundles that are
* tracked. A BundleTrackerCustomizer is called when a bundle is
* being added to a BundleTracker. The
* BundleTrackerCustomizer can then return an object for the
* tracked bundle. A BundleTrackerCustomizer is also called when a
* tracked bundle is modified or has been removed from a
* BundleTracker.
*
*
* The methods in this interface may be called as the result of a
* BundleEvent being received by a BundleTracker.
* Since BundleEvents are received synchronously by the
* BundleTracker, it is highly recommended that implementations of
* these methods do not alter bundle states while being synchronized on any
* object.
*
*
* The BundleTracker class is thread-safe. It does not call a
* BundleTrackerCustomizer while holding any locks.
* BundleTrackerCustomizer implementations must also be
* thread-safe.
*
* @ThreadSafe
* @version $Revision: 5874 $
* @since 1.4
*/
public interface BundleTrackerCustomizer {
/**
* A bundle is being added to the BundleTracker.
*
*
* This method is called before a bundle which matched the search parameters
* of the BundleTracker is added to the
* BundleTracker. This method should return the object to be
* tracked for the specified Bundle. The returned object is
* stored in the BundleTracker and is available from the
* {@link BundleTracker#getObject(Bundle) getObject} method.
*
* @param bundle The Bundle being added to the
* BundleTracker.
* @param event The bundle event which caused this customizer method to be
* called or null if there is no bundle event associated
* with the call to this method.
* @return The object to be tracked for the specified Bundle
* object or null if the specified Bundle
* object should not be tracked.
*/
public Object addingBundle(Bundle bundle, BundleEvent event);
/**
* A bundle tracked by the BundleTracker has been modified.
*
*
* This method is called when a bundle being tracked by the
* BundleTracker has had its state modified.
*
* @param bundle The Bundle whose state has been modified.
* @param event The bundle event which caused this customizer method to be
* called or null if there is no bundle event associated
* with the call to this method.
* @param object The tracked object for the specified bundle.
*/
public void modifiedBundle(Bundle bundle, BundleEvent event,
Object object);
/**
* A bundle tracked by the BundleTracker has been removed.
*
*
* This method is called after a bundle is no longer being tracked by the
* BundleTracker.
*
* @param bundle The Bundle that has been removed.
* @param event The bundle event which caused this customizer method to be
* called or null if there is no bundle event associated
* with the call to this method.
* @param object The tracked object for the specified bundle.
*/
public void removedBundle(Bundle bundle, BundleEvent event,
Object object);
}