MavenVersionFinder.java

/*******************************************************************************
 * Copyright (c) 2004, 2006
 * Thomas Hallgren, Kenneth Olwing, Mitch Sonies
 * Pontus Rydin, Nils Unden, Peer Torngren
 * The code, documentation and other materials contained herein have been
 * licensed under the Eclipse Public License - v 1.0 by the individual
 * copyright holders listed above, as Initial Contributors under such license.
 * The text of such license is available at www.eclipse.org.
 *******************************************************************************/
package org.eclipse.buckminster.maven.internal;

import java.net.URI;
import java.net.URL;
import java.util.ArrayList;
import java.util.List;

import org.eclipse.buckminster.core.ctype.IComponentType;
import org.eclipse.buckminster.core.reader.URLCatalogReaderType;
import org.eclipse.buckminster.core.resolver.NodeQuery;
import org.eclipse.buckminster.core.resolver.ResolverDecisionType;
import org.eclipse.buckminster.core.rmap.model.Provider;
import org.eclipse.buckminster.core.version.AbstractVersionFinder;
import org.eclipse.buckminster.core.version.VersionHelper;
import org.eclipse.buckminster.core.version.VersionMatch;
import org.eclipse.buckminster.maven.Messages;
import org.eclipse.buckminster.runtime.MonitorUtils;
import org.eclipse.core.runtime.CoreException;
import org.eclipse.core.runtime.IPath;
import org.eclipse.core.runtime.IProgressMonitor;
import org.eclipse.core.runtime.Path;
import org.eclipse.equinox.p2.metadata.Version;
import org.eclipse.equinox.p2.metadata.VersionRange;
import org.eclipse.osgi.util.NLS;

/**
 * The URL used by the MavenReader denotes the group directory within one
 * specific repository. The format must be <br/>
 * <code>[<schema>][//<authority>]<path to group>#<artifact></code>
 * <br/>
 * The ability to search trhough multiple repositories is obtained by using the
 * <code>SearchPath</code> or the <code>ResourceMap</code>. The
 * 
 * @author Thomas Hallgren
 */
public class MavenVersionFinder extends AbstractVersionFinder implements ILocationResolver {
	private static final String[] allowedExtensions = new String[] { ".jar", ".mar" }; //$NON-NLS-1$ //$NON-NLS-2$

	private final MavenReaderType readerType;

	private final IMapEntry mapEntry;

	private final URI uri;

	private URL[] fileList;

	public MavenVersionFinder(MavenReaderType readerType, Provider provider, IComponentType ctype, NodeQuery query) throws CoreException {
		super(provider, ctype, query);
		this.readerType = readerType;
		this.uri = readerType.getURI(provider, query.getProperties());
		this.mapEntry = MavenReaderType.getGroupAndArtifact(provider, query.getComponentRequest());
	}

	@Override
	public void close() {
		fileList = null;
	}

	@Override
	public VersionMatch getBestVersion(IProgressMonitor monitor) throws CoreException {
		VersionMatch best = null;
		for (VersionMatch candidate : getComponentVersions(monitor))
			best = getBestVersion(candidate, best);
		return best;
	}

	@Override
	public URI getURI() {
		return uri;
	}

	VersionMatch getBestVersion(VersionMatch a, VersionMatch b) {
		if (a == null)
			return b;

		if (b == null)
			return a;

		Version av = a.getVersion();
		Version bv = b.getVersion();
		VersionMatch selected;
		VersionMatch rejected;

		String msgFormat = Messages._0_has_no_version;
		if (av == null) {
			if (bv == null)
				return a;

			rejected = a;
			selected = b;
		} else if (bv == null) {
			rejected = b;
			selected = a;
		} else {
			msgFormat = Messages._0_is_a_better_match;
			if (getQuery().compare(a, b) > 0) {
				rejected = b;
				selected = a;
			} else {
				rejected = a;
				selected = b;
			}
		}
		logDecision(ResolverDecisionType.MATCH_REJECTED, rejected, NLS.bind(msgFormat, selected));
		return selected;
	}

	/**
	 * Returns an array of versions known to this repository.
	 * 
	 * @return known versions or <code>null</code> if not applicable.
	 * @throws CoreException
	 */
	List<VersionMatch> getComponentVersions(IProgressMonitor monitor) throws CoreException {
		NodeQuery query = getQuery();
		VersionRange range = query.getVersionRange();
		if (range == null)
			range = VersionRange.emptyRange;
		else {
			if (range.getFormat().equals(VersionHelper.getOSGiFormat()))
				//
				// Convert the OSGi version to a Triplet version instead.
				//
				range = VersionHelper.createRange(MavenComponentType.getTripletFormat(), range.toString());
		}

		List<VersionMatch> versions = new ArrayList<VersionMatch>();
		String artifact = mapEntry.getArtifactId() + '-';
		int artifactLen = artifact.length();
		for (URL url : getFileList(range, monitor)) {
			IPath path = Path.fromPortableString(url.getPath());
			int segCnt = path.segmentCount();
			if (segCnt < 1)
				continue;

			String fileName = path.segment(segCnt - 1);
			if (!fileName.startsWith(artifact))
				continue;

			String extension = null;
			for (String allowedExtension : allowedExtensions) {
				if (fileName.endsWith(allowedExtension)) {
					extension = allowedExtension;
					break;
				}
			}
			if (extension == null)
				continue;

			String versionStr = fileName.substring(artifactLen, fileName.length() - extension.length());
			VersionMatch versionMatch = MavenComponentType.createVersionMatch(versionStr, fileName + '/' + versionStr);
			if (versionMatch != null && query.isMatch(versionMatch))
				versions.add(versionMatch);
		}
		return versions;
	}

	IMapEntry getMapEntry() {
		return mapEntry;
	}

	MavenReaderType getReaderType() {
		return readerType;
	}

	private URL[] createFileList(VersionRange designator, IProgressMonitor monitor) throws CoreException {
		StringBuilder pbld = new StringBuilder();
		readerType.appendFolder(pbld, uri.getPath());
		readerType.appendFolder(pbld, mapEntry.getGroupId());
		readerType.appendFolder(pbld, "jars"); //$NON-NLS-1$
		URL jarsURL = MavenReaderType.createURL(uri, pbld.toString());
		return URLCatalogReaderType.list(jarsURL, getConnectContext(), monitor);
	}

	private URL[] getFileList(VersionRange designator, IProgressMonitor monitor) throws CoreException {
		if (fileList == null)
			fileList = createFileList(designator, monitor);
		else
			MonitorUtils.complete(monitor);
		return fileList;
	}
}