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AspectJ tools most notably contains the AspectJ compiler (AJC). AJC applies aspects to Java classes during compilation, fully replacing Javac for plain Java classes and also compiling native AspectJ or annotation-based @AspectJ syntax. Furthermore, AJC can weave aspects into existing class files in a post-compile binary weaving step. This library is a superset of AspectJ weaver and hence also of AspectJ runtime.

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/*******************************************************************************
 * Copyright (c) 2005, 2021 IBM Corporation and others.
 *
 * This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License 2.0
 * which accompanies this distribution, and is available at
 * https://www.eclipse.org/legal/epl-2.0/
 *
 * SPDX-License-Identifier: EPL-2.0
 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package org.eclipse.osgi.internal.loader.buddy;

import java.io.IOException;
import java.net.URL;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.Enumeration;
import java.util.Map;
import org.eclipse.osgi.container.ModuleContainer;
import org.eclipse.osgi.container.ModuleWire;
import org.eclipse.osgi.container.ModuleWiring;
import org.eclipse.osgi.internal.container.Capabilities;
import org.eclipse.osgi.internal.loader.BundleLoader;
import org.osgi.framework.namespace.HostNamespace;
import org.osgi.framework.namespace.PackageNamespace;
import org.osgi.framework.wiring.BundleCapability;
import org.osgi.framework.wiring.BundleRevision;
import org.osgi.framework.wiring.FrameworkWiring;
import org.osgi.resource.Namespace;

/**
 * Global policy is an implementation of a buddy policy. It is responsible
 * for looking up a class within the global set of exported classes. If multiple
 * version of the same package are exported in the system, the exported package
 * with the highest version will be returned.
 */
public class GlobalPolicy implements IBuddyPolicy {
	private FrameworkWiring frameworkWiring;

	public GlobalPolicy(FrameworkWiring frameworkWiring) {
		this.frameworkWiring = frameworkWiring;
	}

	@Override
	public Class loadClass(String name) {
		return getExportingBundles(BundleLoader.getPackageName(name)) //
				.stream().findFirst().map(b -> b.findClassNoParentNoException(name)).orElse(null);
	}

	@Override
	public URL loadResource(String name) {
		return getExportingBundles(BundleLoader.getResourcePackageName(name)) //
				.stream().findFirst().map(b -> b.findResource(name)).orElse(null);
	}

	@Override
	public Enumeration loadResources(String name) {
		Enumeration results = null;
		Collection exporters = getExportingBundles(name);
		for (BundleLoader exporter : exporters) {
			try {
				results = BundleLoader.compoundEnumerations(results, exporter.findResources(name));
			}catch (IOException e) {
				//ignore IO problems and try next package
			}
		}
		return results;
	}

	private Collection getExportingBundles(String pkgName) {
		Collection result = new ArrayList<>();
		String filter = "(" + PackageNamespace.PACKAGE_NAMESPACE + "=" + pkgName + ")"; //$NON-NLS-1$ //$NON-NLS-2$ //$NON-NLS-3$
		Map directives = Collections.singletonMap(Namespace.REQUIREMENT_FILTER_DIRECTIVE, filter);
		Map attributes = Collections.singletonMap(Capabilities.SYNTHETIC_REQUIREMENT, Boolean.TRUE);
		Collection packages = frameworkWiring.findProviders(
				ModuleContainer.createRequirement(PackageNamespace.PACKAGE_NAMESPACE, directives, attributes));
		for (BundleCapability pkg : packages) {
			ModuleWiring wiring = (ModuleWiring) pkg.getRevision().getWiring();
			if (wiring != null) {
				if ((pkg.getRevision().getTypes() & BundleRevision.TYPE_FRAGMENT) != 0) {
					// use the hosts
					if (wiring != null) {
						for (ModuleWire hostWire : wiring.getRequiredModuleWires(HostNamespace.HOST_NAMESPACE)) {
							result.add((BundleLoader) hostWire.getProviderWiring().getModuleLoader());
						}
					}
				} else {
					result.add((BundleLoader) wiring.getModuleLoader());
				}
			}
		}
		return result;
	}
}