org.apache.sling.commons.osgi.SortingServiceTracker Maven / Gradle / Ivy
/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you 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.apache.sling.commons.osgi;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.List;
import org.osgi.framework.BundleContext;
import org.osgi.framework.ServiceReference;
import org.osgi.util.tracker.ServiceTracker;
/**
* Implementation providing a sorted list of services
* by service ranking.
*/
public class SortingServiceTracker
extends ServiceTracker {
private int lastCount = -1;
private int lastRefCount = -1;
private List sortedServiceCache;
private List sortedReferences;
/**
* Constructor
* @param context Bundle context
* @param clazz Class
*/
public SortingServiceTracker(final BundleContext context,
final String clazz) {
super(context, clazz, null);
}
/**
* @see org.osgi.util.tracker.ServiceTracker#removedService(org.osgi.framework.ServiceReference, java.lang.Object)
*/
@Override
public void removedService(ServiceReference reference, Object service) {
this.sortedServiceCache = null;
this.sortedReferences = null;
this.context.ungetService(reference);
}
/**
* @see org.osgi.util.tracker.ServiceTrackerCustomizer#modifiedService(org.osgi.framework.ServiceReference, java.lang.Object)
*/
@Override
public void modifiedService(ServiceReference reference, Object service) {
this.sortedServiceCache = null;
this.sortedReferences = null;
}
/**
* @see org.osgi.util.tracker.ServiceTrackerCustomizer#addingService(org.osgi.framework.ServiceReference)
*/
@Override
public Object addingService(ServiceReference reference) {
this.sortedServiceCache = null;
this.sortedReferences = null;
return context.getService(reference);
}
/**
* Return a sorted list of the services.
* @return Service list
*/
public List getSortedServices() {
List result = this.sortedServiceCache;
if ( result == null || this.lastCount < this.getTrackingCount() ) {
this.lastCount = this.getTrackingCount();
final ServiceReference[] references = this.getServiceReferences();
if ( references == null || references.length == 0 ) {
result = Collections.emptyList();
} else {
Arrays.sort(references);
result = new ArrayList();
for(int i=0;i getSortedServiceReferences() {
List result = this.sortedReferences;
if ( result == null || this.lastRefCount < this.getTrackingCount() ) {
this.lastRefCount = this.getTrackingCount();
final ServiceReference[] references = this.getServiceReferences();
if ( references == null || references.length == 0 ) {
result = Collections.emptyList();
} else {
Arrays.sort(references);
result = new ArrayList();
for(int i=0;i