Introduced "generator" configuration option to be able to manipulate the thrift --gen option

src/main/java/org/apache/thrift/maven/AbstractThriftMojo.java

@@ -75,6 +75,15 @@ abstract class AbstractThriftMojo extends AbstractMojo {
      */
     private String thriftExecutable;
 
+    /**
+     * This string is passed to the {@code --gen} option of the {@code thrift} parameter. By default
+     * it will generate Java output. The main reason for this option is to be able to add options
+     * to the Java generator - if you generate something else, you're on your own.
+     * 
+     * @parameter default-value="java"
+     */
+    private String generator;
+    
     /**
      * @parameter
      */
@@ -140,6 +149,7 @@ abstract class AbstractThriftMojo extends AbstractMojo {
                     cleanDirectory(outputDirectory);
 
                     Thrift thrift = new Thrift.Builder(thriftExecutable, outputDirectory)
+                            .setGenerator(generator)
                             .addThriftPathElement(thriftSourceRoot)
                             .addThriftPathElements(derivedThriftPathElements)
                             .addThriftPathElements(asList(additionalThriftPathElements))
@@ -171,6 +181,7 @@ abstract class AbstractThriftMojo extends AbstractMojo {
         checkNotNull(project, "project");
         checkNotNull(projectHelper, "projectHelper");
         checkNotNull(thriftExecutable, "thriftExecutable");
+        checkNotNull(generator, "generator");
         final File thriftSourceRoot = getThriftSourceRoot();
         checkNotNull(thriftSourceRoot);
         checkArgument(!thriftSourceRoot.isFile(), "thriftSourceRoot is a file, not a diretory");

src/main/java/org/apache/thrift/maven/Thrift.java

@@ -33,6 +33,7 @@ final class Thrift {
     final static String GENERATED_JAVA = "gen-java";
 
     private final String executable;
+    private final String generator;
     private final ImmutableSet<File> thriftPathElements;
     private final ImmutableSet<File> thriftFiles;
     private final File javaOutputDirectory;
@@ -43,14 +44,16 @@ final class Thrift {
      * Constructs a new instance. This should only be used by the {@link Builder}.
      *
      * @param executable          The path to the {@code thrift} executable.
+     * @param generator           The value for the {@code --gen} option.
      * @param thriftPath          The directories in which to search for imports.
      * @param thriftFiles         The thrift source files to compile.
      * @param javaOutputDirectory The directory into which the java source files
      *                            will be generated.
      */
-    private Thrift(String executable, ImmutableSet<File> thriftPath,
+    private Thrift(String executable, String generator, ImmutableSet<File> thriftPath,
                    ImmutableSet<File> thriftFiles, File javaOutputDirectory) {
         this.executable = checkNotNull(executable, "executable");
+        this.generator = checkNotNull(generator, "generator");
         this.thriftPathElements = checkNotNull(thriftPath, "thriftPath");
         this.thriftFiles = checkNotNull(thriftFiles, "thriftFiles");
         this.javaOutputDirectory = checkNotNull(javaOutputDirectory, "javaOutputDirectory");
@@ -101,7 +104,7 @@ final class Thrift {
         command.add("-o");
         command.add(javaOutputDirectory.toString());
         command.add("--gen");
-        command.add("java");
+        command.add(generator);
         command.add(thriftFile.toString());
         return ImmutableList.copyOf(command);
     }
@@ -151,6 +154,7 @@ final class Thrift {
         private final File javaOutputDirectory;
         private Set<File> thriftPathElements;
         private Set<File> thriftFiles;
+        private String generator;
 
         /**
          * Constructs a new builder. The two parameters are present as they are
@@ -191,6 +195,19 @@ final class Thrift {
             return this;
         }
 
+        /**
+         * Adds the option string for the Thrift executable's {@code --gen} parameter.
+         * 
+         * @param generator
+         * @return The builder
+         * @throws NullPointerException If {@code generator} is {@code null}.
+         */
+        public Builder setGenerator(String generator) {
+            checkNotNull(generator);
+            this.generator = generator;
+            return this;
+        }
+
         private void checkThriftFileIsInThriftPath(File thriftFile) {
             assert thriftFile.isFile();
             checkState(checkThriftFileIsInThriftPathHelper(thriftFile.getParentFile()));
@@ -250,7 +267,7 @@ final class Thrift {
          */
         public Thrift build() {
             checkState(!thriftFiles.isEmpty());
-            return new Thrift(executable, ImmutableSet.copyOf(thriftPathElements),
+            return new Thrift(executable, generator, ImmutableSet.copyOf(thriftPathElements),
                 ImmutableSet.copyOf(thriftFiles), javaOutputDirectory);
         }
     }

src/test/java/org/apache/thrift/maven/TestThrift.java

@@ -36,7 +36,9 @@ public class TestThrift {
         idlDir = new File(testResourceDir, "idl");
         genJavaDir = new File(testRootDir, Thrift.GENERATED_JAVA);
         builder = new Thrift.Builder("thrift", testRootDir);
-        builder.addThriftPathElement(idlDir);
+        builder
+            .setGenerator("java")
+            .addThriftPathElement(idlDir);
     }
 
     @Test
@@ -59,6 +61,12 @@ public class TestThrift {
             new File(testRootDir, "shared/SharedService.java").exists());
     }
 
+    @Test
+    public void testThriftCompileWithGeneratorOption() throws Exception {
+        builder.setGenerator("java:private-members,hashcode");
+        testThriftCompile();
+    }
+
     @Test
     public void testThriftMultipleFileCompile() throws Exception {
         final File sharedThrift = new File(idlDir, "shared.thrift");