A maven mojo that utilizes allows the use of the bnd generate function

This Mojo triggers the generate mechanism and can make use of the
external plugins of bnd if provided as configuration.

Signed-off-by: Juergen Albert <j.albert@data-in-motion.biz>

biz.aQute.bnd.maven/src/aQute/bnd/maven/lib/configuration/Configurations.java

@@ -0,0 +1,134 @@
+package aQute.bnd.maven.lib.configuration;
+
+import java.io.File;
+import java.util.List;
+import java.util.Objects;
+import java.util.Optional;
+
+import org.apache.maven.model.Plugin;
+import org.apache.maven.model.PluginExecution;
+import org.apache.maven.model.PluginManagement;
+import org.apache.maven.plugin.MojoExecution;
+import org.apache.maven.project.MavenProject;
+import org.codehaus.plexus.util.xml.Xpp3Dom;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import aQute.bnd.build.Project;
+import aQute.bnd.osgi.Processor;
+import aQute.lib.io.IO;
+import aQute.lib.utf8properties.UTF8Properties;
+
+/**
+ * A helper to read configurations for maven plugins consistently over the
+ * various Mojos.
+ *
+ * @author Juergen Albert
+ */
+public class Configurations {
+
+	protected final static Logger logger = LoggerFactory.getLogger(Configurations.class);
+
+	public static File loadProperties(Processor processor, MavenProject project, MojoExecution mojoExecution)
+		throws Exception {
+		// Load parent project properties first
+		loadParentProjectProperties(processor, project, mojoExecution);
+
+		// Load current project properties
+		Xpp3Dom configuration = Optional.ofNullable(project.getBuildPlugins())
+			.flatMap(new FlatMapHelper(mojoExecution)::getConfiguration)
+			.orElseGet(Configurations::defaultConfiguration);
+		return loadProjectProperties(processor, project, project, configuration);
+	}
+
+	private static void loadParentProjectProperties(Processor builder, MavenProject currentProject,
+		MojoExecution mojoExecution) throws Exception {
+		MavenProject parentProject = currentProject.getParent();
+		if (parentProject == null) {
+			return;
+		}
+		loadParentProjectProperties(builder, parentProject, mojoExecution);
+
+		// Get configuration from parent project
+		Xpp3Dom configuration = Optional.ofNullable(parentProject.getBuildPlugins())
+			.flatMap(new FlatMapHelper(mojoExecution)::getConfiguration)
+			.orElse(null);
+		if (configuration != null) {
+			// Load parent project's properties
+			loadProjectProperties(builder, parentProject, parentProject, configuration);
+			return;
+		}
+
+		// Get configuration in project's pluginManagement
+		configuration = Optional.ofNullable(currentProject.getPluginManagement())
+			.map(PluginManagement::getPlugins)
+			.flatMap(new FlatMapHelper(mojoExecution)::getConfiguration)
+			.orElseGet(Configurations::defaultConfiguration);
+		// Load properties from parent project's bnd file or configuration in
+		// project's pluginManagement
+		loadProjectProperties(builder, parentProject, currentProject, configuration);
+	}
+
+	private static File loadProjectProperties(Processor processor, MavenProject bndProject, MavenProject pomProject,
+		Xpp3Dom configuration) throws Exception {
+		// check for bnd file configuration
+		File baseDir = bndProject.getBasedir();
+		if (baseDir != null) { // file system based pom
+			File pomFile = bndProject.getFile();
+			processor.updateModified(pomFile.lastModified(), "POM: " + pomFile);
+			// check for bnd file
+			Xpp3Dom bndfileElement = configuration.getChild("bndfile");
+			String bndFileName = (bndfileElement != null) ? bndfileElement.getValue() : Project.BNDFILE;
+			File bndFile = IO.getFile(baseDir, bndFileName);
+			if (bndFile.isFile()) {
+				logger.debug("loading bnd properties from file: {}", bndFile);
+				// we use setProperties to handle -include
+				processor.setProperties(bndFile.getParentFile(), processor.loadProperties(bndFile));
+				return bndFile;
+			}
+			// no bnd file found, so we fall through
+		}
+
+		// check for bnd-in-pom configuration
+		baseDir = pomProject.getBasedir();
+		File pomFile = pomProject.getFile();
+		if (baseDir != null) {
+			processor.updateModified(pomFile.lastModified(), "POM: " + pomFile);
+		}
+		Xpp3Dom bndElement = configuration.getChild("bnd");
+		if (bndElement != null) {
+			logger.debug("loading bnd properties from bnd element in pom: {}", pomProject);
+			UTF8Properties properties = new UTF8Properties();
+			properties.load(bndElement.getValue(), pomFile, processor);
+			// we use setProperties to handle -include
+			processor.setProperties(baseDir, properties.replaceHere(baseDir));
+		}
+		return pomFile;
+	}
+
+	private static class FlatMapHelper {
+
+		private MojoExecution mojoExecution;
+
+		public FlatMapHelper(MojoExecution mojoExecution) {
+			this.mojoExecution = mojoExecution;
+		}
+
+		public Optional<Xpp3Dom> getConfiguration(List<Plugin> plugins) {
+			return plugins.stream()
+				.filter(p -> Objects.equals(p, mojoExecution.getPlugin()))
+				.map(Plugin::getExecutions)
+				.flatMap(List::stream)
+				.filter(e -> Objects.equals(e.getId(), mojoExecution.getExecutionId()))
+				.findFirst()
+				.map(PluginExecution::getConfiguration)
+				.map(Xpp3Dom.class::cast)
+				.map(Xpp3Dom::new);
+		}
+	}
+
+	private static Xpp3Dom defaultConfiguration() {
+		return new Xpp3Dom("configuration");
+	}
+
+}

biz.aQute.bnd.maven/src/aQute/bnd/maven/lib/configuration/package-info.java

@@ -1,4 +1,4 @@
-@Version("1.1.0")
+@Version("1.2.0")
 @Export
 package aQute.bnd.maven.lib.configuration;