MavenUtils.java

/*
 * Copyright 2009 Alin Dreghiciu.
 *
 * Licensed 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.ops4j.pax.exam;

import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;
import java.net.URL;
import java.util.Properties;

import org.ops4j.pax.exam.options.MavenArtifactUrlReference;

/**
 * Utility methods related to Apache Maven.
 *
 * @author Alin Dreghiciu (adreghiciu@gmail.com)
 * @since 0.3.1, March 09, 2009
 */
public class MavenUtils {

    /**
     * Utility class. Ment to be used via the static factory methods.
     */
    private MavenUtils() {
        // utility class
    }

    /**
     * Gets the artifact version out of dependencies file. The dependencies file had to be generated
     * by using the maven plugin.
     *
     * @param groupId
     *            artifact group id
     * @param artifactId
     *            artifact id
     *
     * @return found version
     *
     * @throws RuntimeException
     *             - If artifact version cannot be found
     */
    public static String getArtifactVersion(final String groupId, final String artifactId) {
        final Properties dependencies = new Properties();
        InputStream depInputStream = null;
        try {
            String depFilePath = "META-INF/maven/dependencies.properties";
            URL fileURL = MavenUtils.class.getClassLoader().getResource(depFilePath);
            if (fileURL == null) {
                // try the TCCL for getResource
                fileURL = Thread.currentThread().getContextClassLoader().getResource(depFilePath);
            }
            if (fileURL == null) {
                throw new FileNotFoundException("File [" + depFilePath + "] could not be found in classpath");
            }
            depInputStream = fileURL.openStream();
            dependencies.load(depInputStream);
            final String version = dependencies
                .getProperty(groupId + "/" + artifactId + "/version");
            if (version == null) {
                throw new IllegalArgumentException(
                    "Could not resolve version. Do you have a dependency for " + groupId + "/"
                        + artifactId + " in your maven project?");
            }
            return version;
        }
        catch (IOException e) {
            throw new IllegalArgumentException("Could not resolve version for groupId:" + groupId
                + " artifactId:" + artifactId
                + " by reading the dependency information generated by maven.", e);
        }
        finally {
            if (depInputStream != null) {
                try {
                    depInputStream.close();
                }
                catch (IOException e) {
                    // ignore exceptions on close.
                }
            }
        }
    }

    /**
     * Utility method for creating an artifact version resolver that will get the version out of
     * maven project.
     *
     * @return version resolver
     */
    public static MavenArtifactUrlReference.VersionResolver asInProject() {
        return new MavenArtifactUrlReference.VersionResolver() {

            @Override
            public String getVersion(final String groupId, final String artifactId) {
                return getArtifactVersion(groupId, artifactId);
            }

        };
    }
}