util/org.eclipse.virgo.util.osgi/src/main/java/org/eclipse/virgo/util/osgi/BundleUtils.java

/*******************************************************************************
 * Copyright (c) 2008, 2010 VMware Inc.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *   VMware Inc. - initial contribution
 *******************************************************************************/

package org.eclipse.virgo.util.osgi;

import org.osgi.framework.Bundle;
import org.osgi.framework.wiring.BundleCapability;
import org.osgi.framework.wiring.BundleRevision;
import org.osgi.framework.wiring.BundleWiring;

import java.util.HashSet;
import java.util.List;
import java.util.Set;

import static org.osgi.framework.namespace.PackageNamespace.PACKAGE_NAMESPACE;
import static org.osgi.framework.wiring.BundleRevision.TYPE_FRAGMENT;

/**
 * <code>BundleUtils</code> provides utility methods for interacting with {@link Bundle Bundles}.
 * <p />
 *
 * <strong>Concurrent Semantics</strong><br />
 * Thread-safe
 *
 */
public final class BundleUtils {

    /**
     * Queries whether the supplied {@link Bundle} is a fragment
     *
     * @param bundle the <code>Bundle</code>.
     * @return <code>true</code> if the <code>Bundle</code> is fragment, otherwise <code>false</code>.
     */
    public static boolean isFragmentBundle(Bundle bundle) {
        BundleRevision rev = bundle.adapt(BundleRevision.class);
        return rev != null && (rev.getTypes() & TYPE_FRAGMENT)!= 0;
    }

    /**
     * Queries whether the supplied {@link Bundle} is the system bundle.
     *
     * @param bundle the <code>Bundle</code>.
     * @return <code>true</code> if <code>bundle</code> is the system bundle, otherwise <code>false</code>.
     */
    public static boolean isSystemBundle(Bundle bundle) {
        return bundle != null && bundle.getBundleId() == 0;
    }

    /**
     * Get exported packages of the supplied {@link Bundle}.
     *
     * @param bundle the <code>Bundle</code>.
     * @return <code>Set</code> of exported packages as plain strings.
     */
    public static Set<String> getExportedPackages(Bundle bundle) {
        Set<String> packagesExportedBySystemBundle = new HashSet<>(30);
        BundleWiring systemBundleWiring = bundle.adapt(BundleWiring.class);
        List<BundleCapability> packageWires = systemBundleWiring.getCapabilities(PACKAGE_NAMESPACE);
        for (BundleCapability packageWire : packageWires) {
            packagesExportedBySystemBundle.add((String) packageWire.getAttributes()
                    .get(PACKAGE_NAMESPACE));
        }
        return packagesExportedBySystemBundle;
    }

    /**
     * Get the packages exported by the given system {@link Bundle}.
     *
     * @param bundle the <code>Bundle</code>.
     * @return <code>Set<String></code> of exported packages if <code>bundle</code> is the system bundle.
     * @throws IllegalArgumentException if given bundle is not the system bundle or <code>null</code>.
     */
    public static Set<String> getPackagesExportedBySystemBundle(Bundle bundle) {
        if (!isSystemBundle(bundle)) {
            throw new IllegalArgumentException("Given bundle is not the system bundle");
        }
        return getExportedPackages(bundle);
    }
}