Support addition of license header to generated files

modello-core/src/main/java/org/codehaus/modello/ModelloParameterConstants.java

@@ -80,5 +80,12 @@ public class ModelloParameterConstants {
      */
     public static final String XSD_ENFORCE_MANDATORY_ELEMENTS = "modello.xsd.enforce.mandatory.element";
 
+    /**
+     * The license text as string, to be added to generated files, if needed.
+     *
+     * @since 2.3.1
+     */
+    public static final String LICENSE_TEXT = "modello.license.text";
+
     private ModelloParameterConstants() {}
 }

modello-core/src/main/java/org/codehaus/modello/plugin/AbstractModelloGenerator.java

@@ -66,6 +66,8 @@ public abstract class AbstractModelloGenerator implements ModelloGenerator {
 
     private String encoding;
 
+    private String licenseText;
+
     @Inject
     private BuildContext buildContext;
 
@@ -82,9 +84,12 @@ protected void initialize(Model model, Properties parameters) throws ModelloExce
 
         generatedVersion = new Version(version);
 
-        packageWithVersion = Boolean.valueOf(getParameter(parameters, ModelloParameterConstants.PACKAGE_WITH_VERSION));
+        packageWithVersion =
+                Boolean.parseBoolean(getParameter(parameters, ModelloParameterConstants.PACKAGE_WITH_VERSION));
 
         encoding = parameters.getProperty(ModelloParameterConstants.ENCODING);
+
+        licenseText = parameters.getProperty(ModelloParameterConstants.LICENSE_TEXT);
     }
 
     protected Model getModel() {
@@ -108,13 +113,27 @@ protected String getEncoding() {
     }
 
     protected String getHeader() {
+        String header = getLicenseHeader();
+        if (header == null) {
+            return getGeneratedHeader();
+        }
+        header += System.lineSeparator();
+        header += getGeneratedHeader();
+        return header;
+    }
+
+    protected String getGeneratedHeader() {
         String version = getClass().getPackage().getImplementationVersion();
-        return "=================== DO NOT EDIT THIS FILE ====================\n"
-                + "Generated by Modello" + ((version == null) ? "" : (' ' + version)) + ",\n"
-                + "any modifications will be overwritten.\n"
+        return "=================== DO NOT EDIT THIS FILE ====================" + System.lineSeparator()
+                + "Generated by Modello" + ((version == null) ? "" : (' ' + version)) + "," + System.lineSeparator()
+                + "any modifications will be overwritten." + System.lineSeparator()
                 + "==============================================================";
     }
 
+    protected String getLicenseHeader() {
+        return licenseText;
+    }
+
     protected boolean isClassInModel(String fieldType, Model model) {
         try {
             return model.getClass(fieldType, generatedVersion) != null;

modello-maven-plugin/src/it/maven-model/pom.xml

@@ -28,12 +28,14 @@
           <models>
             <model>src/main/mdo/maven.mdo</model>
           </models>
+          <licenseText>The license of this file</licenseText>
         </configuration>
         <executions>
           <execution>
             <goals>
               <goal>java</goal>
               <goal>xpp3-reader</goal>
+              <goal>xsd</goal>
             </goals>
           </execution>
         </executions>

modello-maven-plugin/src/it/maven-model/src/main/mdo/maven.mdo

@@ -23,7 +23,10 @@
  |   definition of these types
  |
  -->
-<model>
+<model xmlns="http://codehaus-plexus.github.io/MODELLO/2.3.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+        xsi:schemaLocation="http://codehaus-plexus.github.io/MODELLO/2.3.0 https://codehaus-plexus.github.io/modello/xsd/modello-2.3.0.xsd"
+        xml.namespace="http://maven.apache.org/POM/${version}"
+        xml.schemaLocation="https://maven.apache.org/xsd/maven-${version}.xsd">
   <id>maven</id>
   <name>Maven</name>
   <description><![CDATA[

modello-maven-plugin/src/it/maven-model/verify.groovy

@@ -0,0 +1,32 @@
+/*
+ * 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.
+ */
+
+File generatedSources = new File(basedir, "target/generated-sources/modello")
+File generatedSite = new File(basedir, "target/generated-site/resources/xsd")
+assert generatedSources.exists()
+assert generatedSources.isDirectory()
+assert generatedSite.exists()
+assert generatedSite.isDirectory()
+
+String javaSource = new File(generatedSources, "org/apache/maven/model/Model.java").text
+String xsdSource = new File(generatedSite, "maven-4.0.0.xsd").text
+
+// due formatting issues (empty lines lost) let's stick with trivial license and assertion for now
+assert javaSource.contains("The license of this file")
+assert xsdSource.contains("The license of this file")

modello-maven-plugin/src/main/java/org/codehaus/modello/maven/AbstractModelloGeneratorMojo.java

@@ -25,6 +25,7 @@
 import java.io.File;
 import java.io.FileNotFoundException;
 import java.io.IOException;
+import java.nio.file.Files;
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.List;
@@ -95,6 +96,22 @@ public abstract class AbstractModelloGeneratorMojo extends AbstractMojo {
     @Parameter
     private List<String> packagedVersions = new ArrayList<String>();
 
+    /**
+     * The contents of license header text, verbatim.
+     *
+     * @since 2.3.1
+     */
+    @Parameter
+    private String licenseText;
+
+    /**
+     * The file that contains license header text. If both configured, the {@link #licenseText} prevails.
+     *
+     * @since 2.3.1
+     */
+    @Parameter
+    private File licenseFile;
+
     /**
      * @since 1.0.1
      */
@@ -160,11 +177,27 @@ public void execute() throws MojoExecutionException {
 
         parameters.setProperty(ModelloParameterConstants.PACKAGE_WITH_VERSION, Boolean.toString(packageWithVersion));
 
-        if (packagedVersions.size() > 0) {
+        if (!packagedVersions.isEmpty()) {
             parameters.setProperty(
                     ModelloParameterConstants.ALL_VERSIONS, StringUtils.join(packagedVersions.iterator(), ","));
         }
 
+        if (licenseText != null || licenseFile != null) {
+            String license = "";
+            if (licenseText != null) {
+                // licenseText prevails
+                license = licenseText;
+            } else {
+                try {
+                    // load it up and hard fail if cannot, as it is user misconfiguration
+                    license = String.join(System.lineSeparator(), Files.readAllLines(licenseFile.toPath()));
+                } catch (IOException e) {
+                    throw new MojoExecutionException("Could not load up license text from " + licenseFile, e);
+                }
+            }
+            parameters.setProperty(ModelloParameterConstants.LICENSE_TEXT, license);
+        }
+
         customizeParameters(parameters);
 
         // ----------------------------------------------------------------------