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/*
* 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 calculator.dosgi.impl;
import static org.osgi.framework.Constants.OBJECTCLASS;
import org.osgi.framework.BundleContext;
import org.osgi.framework.Filter;
import org.osgi.framework.InvalidSyntaxException;
import org.osgi.util.tracker.ServiceTracker;
import calculator.dosgi.CalculatorService;
import calculator.dosgi.operations.AddService;
import calculator.dosgi.operations.DivideService;
import calculator.dosgi.operations.MultiplyService;
import calculator.dosgi.operations.SubtractService;
/**
* An implementation of the Calculator service.
*/
public class CalculatorServiceImpl implements CalculatorService {
private ServiceTracker remoteServices;
private ServiceTracker localServices;
public CalculatorServiceImpl() {
super();
}
public CalculatorServiceImpl(BundleContext context) {
super();
Filter remoteFilter = null, localFilter = null;
try {
remoteFilter =
context.createFilter("(&(" + OBJECTCLASS + "=calculator.dosgi.operations.*) (service.imported=*))");
localFilter =
context.createFilter("(&(" + OBJECTCLASS + "=calculator.dosgi.operations.*) (!(service.imported=*)))");
} catch (InvalidSyntaxException e) {
e.printStackTrace();
}
this.remoteServices = new ServiceTracker(context, remoteFilter, null);
remoteServices.open();
this.localServices = new ServiceTracker(context, localFilter, null);
localServices.open();
}
private <T> T getService(Class<T> cls) {
try {
// Wait for 10 seconds until the remote services are imported
remoteServices.waitForService(10000);
} catch (InterruptedException e) {
throw new IllegalStateException(cls.getSimpleName() + " is not available");
}
Object[] remoteObjects = remoteServices.getServices();
if (remoteObjects != null) {
for (Object s : remoteObjects) {
if (cls.isInstance(s)) {
System.out.println("Remote service: " + s);
return cls.cast(s);
}
}
}
Object[] localObjects = localServices.getServices();
if (localObjects != null) {
for (Object s : localObjects) {
if (cls.isInstance(s)) {
System.out.println("Local service: " + s);
return cls.cast(s);
}
}
}
throw new IllegalStateException(cls.getSimpleName() + " is not available");
}
public double add(double n1, double n2) {
return getService(AddService.class).add(n1, n2);
}
public double subtract(double n1, double n2) {
return getService(SubtractService.class).subtract(n1, n2);
}
public double multiply(double n1, double n2) {
return getService(MultiplyService.class).multiply(n1, n2);
}
public double divide(double n1, double n2) {
return getService(DivideService.class).divide(n1, n2);
}
}
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