[MPH-168] effective-pom should support multi-module project

src/main/java/org/apache/maven/plugins/help/EffectivePomMojo.java

@@ -19,6 +19,7 @@
  * under the License.
  */
 
+import java.io.File;
 import java.io.IOException;
 import java.io.StringWriter;
 import java.io.Writer;
@@ -29,8 +30,8 @@
 import java.util.Properties;
 
 import org.apache.maven.model.InputLocation;
-import org.apache.maven.model.Model;
 import org.apache.maven.model.InputSource;
+import org.apache.maven.model.Model;
 import org.apache.maven.model.io.xpp3.MavenXpp3Writer;
 import org.apache.maven.model.io.xpp3.MavenXpp3WriterExOldSupport;
 import org.apache.maven.plugin.MojoExecution;
@@ -55,7 +56,7 @@
  */
 @Mojo( name = "effective-pom", aggregator = true )
 public class EffectivePomMojo
-    extends AbstractEffectiveMojo
+        extends AbstractEffectiveMojo
 {
     // ----------------------------------------------------------------------
     // Mojo parameters
@@ -95,35 +96,55 @@ public class EffectivePomMojo
 
     /**
      * Output POM input location as comments.
-     * 
+     *
      * @since 3.2.0
      */
     @Parameter( property = "verbose", defaultValue = "false" )
     private boolean verbose = false;
 
+    /**
+     * Generate an effective pom for each module individually and
+     * save it in ${project.build.outputDirectory}/effective.pom.xml.
+     *
+     * @since 3.3.0
+     */
+    @Parameter( property = "individual", defaultValue = "false" )
+    private boolean individual = false;
+
     // ----------------------------------------------------------------------
     // Public methods
     // ----------------------------------------------------------------------
 
-    /** {@inheritDoc} */
+    /**
+     * {@inheritDoc}
+     */
     public void execute()
-        throws MojoExecutionException
+            throws MojoExecutionException
     {
         if ( StringUtils.isNotEmpty( artifact ) )
         {
             project = getMavenProject( artifact );
             projects = Collections.singletonList( project );
         }
+        if ( individual )
+        {
+            generateIndividualEffectivePom();
+        }
+        else
+        {
+            generateSingleEffectivePom();
+        }
+    }
 
+    private void generateSingleEffectivePom() throws MojoExecutionException
+    {
         StringWriter w = new StringWriter();
         String encoding = output != null ? project.getModel().getModelEncoding()
-                                : System.getProperty( "file.encoding" );
+                : System.getProperty( "file.encoding" );
         XMLWriter writer =
-            new PrettyPrintXMLWriter( w, StringUtils.repeat( " ", XmlWriterUtil.DEFAULT_INDENTATION_SIZE ),
-                                      encoding, null );
+                getPrettyPrintXMLWriterForEffectivePom( w, encoding );
 
         writeHeader( writer );
-
         if ( shouldWriteAllEffectivePOMsInReactor() )
         {
             // outer root element
@@ -140,24 +161,73 @@ public void execute()
         }
 
         String effectivePom = prettyFormat( w.toString(), encoding, false );
+        effectivePom = prettyFormatVerbose( effectivePom );
+        reportEffectivePom( effectivePom, output );
+    }
+
+    private void generateIndividualEffectivePom() throws MojoExecutionException
+    {
+        String encoding = project.getModel().getModelEncoding();
+        if ( shouldWriteAllEffectivePOMsInReactor() )
+        {
+            // outer root element
+            for ( MavenProject subProject : projects )
+            {
+                StringWriter w = new StringWriter();
+                XMLWriter writer =
+                        getPrettyPrintXMLWriterForEffectivePom( w, encoding );
+                writeHeader( writer );
+                writeEffectivePom( subProject, writer );
+                String effectivePom = prettyFormat( w.toString(), encoding, false );
+                effectivePom = prettyFormatVerbose( effectivePom );
+                File effectiveOutput = new File( subProject.getBuild().getDirectory() + "/effective.pom.xml" );
+                reportEffectivePom( effectivePom, effectiveOutput );
+            }
+        }
+        else
+        {
+            StringWriter w = new StringWriter();
+            XMLWriter writer =
+                    getPrettyPrintXMLWriterForEffectivePom( w, encoding );
+            writeHeader( writer );
+            writeEffectivePom( project, writer );
+            String effectivePom = prettyFormat( w.toString(), encoding, false );
+            effectivePom = prettyFormatVerbose( effectivePom );
+            File effectiveOutput = new File( project.getBuild().getDirectory() + "/effective.pom.xml" );
+            reportEffectivePom( effectivePom, effectiveOutput );
+        }
+    }
+
+    private String prettyFormatVerbose( String effectivePom )
+    {
         if ( verbose )
         {
             // tweak location tracking comment, that are put on a separate line by pretty print
             effectivePom = effectivePom.replaceAll( "(?m)>\\s+<!--}", ">  <!-- " );
         }
+        return effectivePom;
+    }
+
+    private PrettyPrintXMLWriter getPrettyPrintXMLWriterForEffectivePom( StringWriter w, String encoding )
+    {
+        return new PrettyPrintXMLWriter( w, StringUtils.repeat( " ", XmlWriterUtil.DEFAULT_INDENTATION_SIZE ),
+                encoding, null );
+    }
 
-        if ( output != null )
+    private void reportEffectivePom( String effectivePom, File effectiveOutput ) throws MojoExecutionException
+    {
+        if ( effectiveOutput != null )
         {
             try
             {
-                writeXmlFile( output, effectivePom );
+                writeXmlFile( effectiveOutput, effectivePom );
             }
             catch ( IOException e )
             {
-                throw new MojoExecutionException( "Cannot write effective-POM to output: " + output, e );
+                throw new MojoExecutionException( "Cannot write effective-POM to output: " + effectiveOutput, e );
             }
 
-            getLog().info( "Effective-POM written to: " + output );
+            getLog().info( "Effective-POM written to: " + effectiveOutput );
         }
         else
         {
@@ -198,11 +268,11 @@ private boolean shouldWriteAllEffectivePOMsInReactor()
      * Method for writing the effective pom informations of the current build.
      *
      * @param project the project of the current build, not null.
-     * @param writer the XML writer , not null, not null.
+     * @param writer  the XML writer , not null, not null.
      * @throws MojoExecutionException if any
      */
     private void writeEffectivePom( MavenProject project, XMLWriter writer )
-        throws MojoExecutionException
+            throws MojoExecutionException
     {
         Model pom = project.getModel();
         cleanModel( pom );
@@ -213,7 +283,7 @@ private void writeEffectivePom( MavenProject project, XMLWriter writer )
             if ( verbose )
             {
                 // try to use Maven core-provided xpp3 extended writer (available since Maven 3.6.1)
-                if ( ! writeMavenXpp3WriterEx( sWriter, pom ) )
+                if ( !writeMavenXpp3WriterEx( sWriter, pom ) )
                 {
                     // xpp3 extended writer not provided by Maven core, use local code
                     new EffectiveWriterExOldSupport().write( sWriter, pom );
@@ -252,19 +322,19 @@ private static void cleanModel( Model pom )
     private void warnWriteMavenXpp3WriterEx( Throwable t )
     {
         getLog().warn( "Unexpected exception while running Maven Model Extended Writer, "
-            + "falling back to old internal implementation.", t );
+                + "falling back to old internal implementation.", t );
     }
 
     private boolean writeMavenXpp3WriterEx( Writer writer, Model model )
-        throws IOException
+            throws IOException
     {
         try
         {
             Class<?> mavenXpp3WriterExClass = Class.forName( "org.apache.maven.model.io.xpp3.MavenXpp3WriterEx" );
             Object mavenXpp3WriterEx = mavenXpp3WriterExClass.getDeclaredConstructor().newInstance();
 
             Method setStringFormatter =
-                mavenXpp3WriterExClass.getMethod( "setStringFormatter", InputLocation.StringFormatter.class );
+                    mavenXpp3WriterExClass.getMethod( "setStringFormatter", InputLocation.StringFormatter.class );
             setStringFormatter.invoke( mavenXpp3WriterEx, new InputLocationStringFormatter() );
 
             Method write = mavenXpp3WriterExClass.getMethod( "write", Writer.class, Model.class );
@@ -312,7 +382,7 @@ private static String toString( InputLocation location )
     }
 
     private static class InputLocationStringFormatter
-        extends InputLocation.StringFormatter
+            extends InputLocation.StringFormatter
     {
 
         public String toString( InputLocation location )
@@ -326,7 +396,7 @@ public String toString( InputLocation location )
      * Xpp3 extended writer extension to improve default InputSource display
      */
     private static class EffectiveWriterExOldSupport
-        extends MavenXpp3WriterExOldSupport
+            extends MavenXpp3WriterExOldSupport
     {
 
         @Override
@@ -337,7 +407,7 @@ public String toString( InputLocation location )
 
         @Override
         protected void writeXpp3DomToSerializer( Xpp3Dom dom, XmlSerializer serializer )
-            throws IOException
+                throws IOException
         {
             // default method uses Xpp3Dom input location tracking, not available in older Maven versions
             // use old Xpp3Dom serialization, without input location tracking