feat: added mvn2jbang command

Author: quintesse

jbang-catalog.json

@@ -44,6 +44,10 @@
     },
     "mdns": {
       "script-ref": "mdns.java"
+    },
+    "mvn2jbang": {
+      "script-ref": "mvn2jbang.java",
+      "description": "Adds a Maven project's dependencies to a JBang script"
     }
   },
   "description": "Quintesse's list of useful JBang scripts!"

mvn2jbang.java

@@ -0,0 +1,75 @@
+//DEPS org.apache.maven:maven-model:3.9.9
+
+import org.apache.maven.model.Model;
+import org.apache.maven.model.io.xpp3.MavenXpp3Reader;
+import org.codehaus.plexus.util.xml.pull.XmlPullParserException;
+
+import java.io.*;
+import java.nio.file.*;
+import java.util.stream.Collectors;
+import java.util.stream.Stream;
+
+public class mvn2jbang {
+
+    static Model readModel(Path pom) throws IOException, XmlPullParserException {
+        try (BufferedReader br = Files.newBufferedReader(pom)) {
+            Model model = readModel(br);
+            model.setPomFile(pom.toFile());
+            return model;
+        }
+    }
+
+    static Model readModel(Reader rdr) throws IOException, XmlPullParserException {
+        try (Reader reader = rdr) {
+            MavenXpp3Reader mavenXpp3Reader = new MavenXpp3Reader();
+            return mavenXpp3Reader.read(reader);
+        }
+    }
+
+    static void writeTags(PrintWriter writer, Model model, boolean usePrefix) {
+        String prefix = usePrefix ? "//" : "";
+        writer.println(prefix + "DEPS " + model.getDependencies().stream()
+                .map(d -> d.getGroupId() + ":" + d.getArtifactId() + ":" + d.getVersion())
+                .collect(Collectors.joining("\n//DEPS ")));
+        if (model.getGroupId() != null && model.getArtifactId() != null && model.getVersion() != null) {
+            writer.println(prefix + "GAV " + model.getGroupId() + ":" + model.getArtifactId() + ":" + model.getVersion());
+        }
+    }
+
+    public static void main(String... args) {
+        if (args.length == 1 && ("--help".equals(args[0])) || args.length > 2) {
+            System.err.println("Usage: mvn2jbang [<pom_file_or_folder>] [<output_file>]");
+            System.exit(1);
+        }
+        try {
+            Path pom = Paths.get(args.length > 0 ? args[0] : "pom.xml");
+            Path output = Paths.get(args.length > 1 ? args[1] : "build.jbang");
+            if (!Files.exists(pom)) {
+                System.err.println("Pom file not found: " + pom);
+                System.exit(2);
+            }
+            Model model = readModel(pom);
+            boolean isJavaFile = output.toString().endsWith(".java");
+            boolean append = isJavaFile && Files.exists(output);
+            Path output2 = append ? Paths.get(output.toString() + ".tmp") : output;
+            try (PrintWriter writer = new PrintWriter(Files.newBufferedWriter(output2))) {
+                writeTags(writer, model, isJavaFile);
+                if (append) {
+                    try (Stream<String> lines = Files.lines(output)) {
+                        lines.forEach(writer::println);
+                    }
+                }
+            } catch (IOException e) {
+                System.err.println("Error writing output: " + e.getMessage());
+                System.exit(4);
+            }
+            if (append) {
+                Files.move(output, Paths.get(output.toString() + ".bak"), StandardCopyOption.REPLACE_EXISTING);
+                Files.move(output2, output);
+            }
+        } catch (IOException | XmlPullParserException e) {
+            System.err.println("Error reading pom: " + e.getMessage());
+            System.exit(3);
+        }
+    }
+}