rsa/src/main/java/org/apache/aries/rsa/core/PackageUtil.java

/*
 * 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.aries.rsa.core;

import org.osgi.framework.Bundle;
import org.osgi.framework.BundleContext;
import org.osgi.framework.ServiceReference;
import org.osgi.service.packageadmin.ExportedPackage;
import org.osgi.service.packageadmin.PackageAdmin;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

@SuppressWarnings("deprecation")
public class PackageUtil {

    public static final Logger LOG = LoggerFactory.getLogger(PackageUtil.class);
    private BundleContext bc;

    public PackageUtil(BundleContext bc) {
        this.bc = bc;
    }
    
    /**
     * Tries to retrieve the version of iClass via the PackageAdmin.
     *
     * @param iClass tThe interface for which the version should be found
     * @return the version of the interface or "0.0.0" if no version information could be found or an error
     *         occurred during the retrieval
     */
    public String getVersion(Class<?> iClass) {
        ServiceReference<PackageAdmin> paRef = bc.getServiceReference(PackageAdmin.class);
        if (paRef != null) {
            PackageAdmin pa = bc.getService(paRef);
            try {
                Bundle b = pa.getBundle(iClass);
                if (b == null) {
                    LOG.info("Unable to find interface version for interface " + iClass.getName()
                            + ". Falling back to 0.0.0");
                    return "0.0.0";
                }
                LOG.debug("Interface source bundle: {}", b.getSymbolicName());

                ExportedPackage[] ep = pa.getExportedPackages(b);
                LOG.debug("Exported Packages of the source bundle: {}", (Object)ep);

                String pack = iClass.getPackage().getName();
                LOG.debug("Looking for Package: {}", pack);
                if (ep != null) {
                    for (ExportedPackage p : ep) {
                        if (p != null
                            && pack.equals(p.getName())) {
                            LOG.debug("found package -> Version: {}", p.getVersion());
                            return p.getVersion().toString();
                        }
                    }
                }
            } finally {
                if (pa != null) {
                    bc.ungetService(paRef);
                }
            }
        } else {
            LOG.error("Was unable to obtain the package admin service -> can't resolve interface versions");
        }

        LOG.info("Unable to find interface version for interface " + iClass.getName()
                 + ". Falling back to 0.0.0");
        return "0.0.0";
    }
}