org.eclipse.osbp.runtime.systemextension/src/org/eclipse/osbp/runtime/systemextension/ResolverHook.java

/**
 * Copyright (c) 2011, 2015 - Lunifera GmbH (Gross Enzersdorf, Austria), Loetz GmbH&Co.KG (69115 Heidelberg, Germany)
 * All rights reserved. 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:
 *         Florian Pirchner - Initial implementation
 */
package org.eclipse.osbp.runtime.systemextension;

import java.util.Collection;
import java.util.Iterator;

import org.osgi.framework.hooks.resolver.ResolverHookFactory;
import org.osgi.framework.wiring.BundleCapability;
import org.osgi.framework.wiring.BundleRequirement;
import org.osgi.framework.wiring.BundleRevision;

public class ResolverHook implements ResolverHookFactory {

	@Override
	public org.osgi.framework.hooks.resolver.ResolverHook begin(
			final Collection<BundleRevision> triggers) {
		return new org.osgi.framework.hooks.resolver.ResolverHook() {

			@Override
			public void filterSingletonCollisions(BundleCapability singleton,
					Collection<BundleCapability> collisionCandidates) {
			}

			@Override
			public void filterResolvable(Collection<BundleRevision> candidates) {

			}

			@Override
			public void filterMatches(BundleRequirement requirement,
					Collection<BundleCapability> candidates) {
				if (requirement.getNamespace().equals("osgi.wiring.bundle")) {

					if (candidates.size() > 1 && containsGuava(candidates)) {
						filterHighestGuava(candidates);
					}
				}
//				if (requirement.getNamespace().equals("osgi.wiring.package")) {
//
//					if (candidates.size() > 1
//							&& containsJavaxAnnotation(candidates)) {
//						removeJavaxAnnotation120(candidates);
//					}
//				}
			}

			@Override
			public void end() {

			}
		};
	}

	/**
	 * Returns true, if the candiates contain guava.
	 * 
	 * @param candidates
	 * @return
	 */
	protected boolean containsGuava(Collection<BundleCapability> candidates) {
		for (BundleCapability cap : candidates) {
			if (cap.getResource().getSymbolicName().equals("com.google.guava")) {
				return true;

			}
		}
		return false;
	}

//	/**
//	 * Returns true if the candiates contain javax.annotation.
//	 * 
//	 * @param candidates
//	 * @return
//	 */
//	protected boolean containsJavaxAnnotation(
//			Collection<BundleCapability> candidates) {
//		for (BundleCapability cap : candidates) {
//			if (cap.getResource().getSymbolicName().equals("javax.annotation")) {
//				return true;
//
//			}
//		}
//		return false;
//	}

//	/**
//	 * Handle javax.annotation bundle. Do not use version 1.2.0.
//	 * 
//	 * @param candidates
//	 */
//	private void removeJavaxAnnotation120(
//			Collection<BundleCapability> candidates) {
//		for (Iterator<BundleCapability> iterator = candidates.iterator(); iterator
//				.hasNext();) {
//			BundleCapability cap = iterator.next();
//			if (cap.getResource().getVersion().toString().startsWith("1.2.0")) {
//				iterator.remove();
//			}
//		}
//	}

	/**
	 * Handle guava bundle. Only use the highest supported version.
	 * 
	 * @param candidates
	 */
	private void filterHighestGuava(Collection<BundleCapability> candidates) {
		BundleCapability highest = getHighestGuava(candidates);
		if (highest != null) {
			for (Iterator<BundleCapability> iterator = candidates.iterator(); iterator
					.hasNext();) {
				BundleCapability cap = iterator.next();
				if (cap != highest) {
					iterator.remove();
				}
			}
		}
	}

	/**
	 * Filters the highest available guava from candidates.
	 * 
	 * @param candidates
	 * @return
	 */
	private BundleCapability getHighestGuava(
			Collection<BundleCapability> candidates) {
		BundleCapability highest = null;
		for (BundleCapability cap : candidates) {
			if (cap.getResource().getSymbolicName().equals("com.google.guava")) {
				if (highest != null) {
					if (highest.getResource().getVersion()
							.compareTo(cap.getResource().getVersion()) < 1) {
						highest = cap;
					}
				} else {
					highest = cap;
				}

			}
		}
		return highest;
	}

}