core-it-support/core-it-plugins/maven-it-plugin-uses-wagon/src/main/java/org/apache/maven/plugin/coreit/LookupWagonMojo.java

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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.apache.maven.plugin.coreit;

import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.util.Properties;

import org.apache.maven.artifact.manager.WagonManager;
import org.apache.maven.plugin.AbstractMojo;
import org.apache.maven.plugin.MojoExecutionException;
import org.apache.maven.plugin.MojoFailureException;
import org.apache.maven.plugins.annotations.Component;
import org.apache.maven.plugins.annotations.LifecyclePhase;
import org.apache.maven.plugins.annotations.Mojo;
import org.apache.maven.plugins.annotations.Parameter;
import org.apache.maven.wagon.Wagon;
import org.apache.maven.wagon.repository.Repository;

/**
 * Loads resources from a class loader used to load a wagon provider. The wagon is merely used to access the extension
 * class loader it came from which is otherwise not accessible to a plugin.
 *
 * @author Benjamin Bentmann
 *
 */
@Mojo(name = "lookup-wagon", defaultPhase = LifecyclePhase.VALIDATE)
public class LookupWagonMojo extends AbstractMojo {

    /**
     * The Wagon manager used to retrieve wagon providers.
     */
    @Component
    private WagonManager wagonManager;

    /**
     * The path to the properties file used to track the results of the wagon lookups.
     */
    @Parameter(property = "wagon.outputFile")
    private File outputFile;

    /**
     * The URLs for which to look up wagons.
     */
    @Parameter
    private String[] urls;

    /**
     * Runs this mojo.
     *
     * @throws MojoFailureException If the attached file has not been set.
     */
    public void execute() throws MojoExecutionException, MojoFailureException {
        Properties loaderProperties = new Properties();

        if (urls != null) {
            for (int i = 0; i < urls.length; i++) {
                String url = urls[i];
                getLog().info("[MAVEN-CORE-IT-LOG] Looking up wagon for URL " + url);

                try {
                    Repository repo = new Repository("repo-" + i, url);
                    Wagon wagon = wagonManager.getWagon(repo);
                    getLog().info("[MAVEN-CORE-IT-LOG]   " + wagon);

                    loaderProperties.setProperty(url + ".hash", Integer.toString(System.identityHashCode(wagon)));
                    loaderProperties.setProperty(
                            url + ".class", wagon.getClass().getName());
                } catch (Exception e) {
                    getLog().warn("[MAVEN-CORE-IT-LOG] Failed to look up wagon for URL " + url, e);
                }
            }
        }

        getLog().info("[MAVEN-CORE-IT-LOG] Creating output file " + outputFile);

        OutputStream out = null;
        try {
            outputFile.getParentFile().mkdirs();
            out = new FileOutputStream(outputFile);
            loaderProperties.store(out, "MAVEN-CORE-IT-LOG");
        } catch (IOException e) {
            throw new MojoExecutionException("Output file could not be created: " + outputFile, e);
        } finally {
            if (out != null) {
                try {
                    out.close();
                } catch (IOException e) {
                    // just ignore
                }
            }
        }

        getLog().info("[MAVEN-CORE-IT-LOG] Created output file " + outputFile);
    }
}