Added code to remove the "gen-java" directory.

This makes the output consistent with other maven code generators.
Additionally added a unit test.

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

@@ -29,6 +29,9 @@ import java.util.Set;
  * @author gak@google.com (Gregory Kick)
  */
 final class Thrift {
+
+    final static String GENERATED_JAVA = "gen-java";
+
     private final String executable;
     private final ImmutableSet<File> thriftPathElements;
     private final ImmutableSet<File> thriftFiles;
@@ -64,7 +67,13 @@ final class Thrift {
         cl.addArguments(buildThriftCommand().toArray(new String[]{}));
         StreamConsumer output = new DefaultConsumer();
         StreamConsumer error = new DefaultConsumer();
-        return CommandLineUtils.executeCommandLine(cl, null, output, error);
+        final int result = CommandLineUtils.executeCommandLine(cl, null, output, error);
+
+        if (result == 0) {
+            moveGeneratedFiles();
+        }
+
+        return result;
     }
 
     /**
@@ -91,6 +100,27 @@ final class Thrift {
         return ImmutableList.copyOf(command);
     }
 
+    private void moveGeneratedFiles() {
+        File genDir = new File(javaOutputDirectory, GENERATED_JAVA);
+        final File[] generatedFiles = genDir.listFiles();
+        for (File generatedFile : generatedFiles) {
+            final String filename = generatedFile.getName();
+            final File targetLocation = new File(javaOutputDirectory, filename);
+            if (targetLocation.exists()) {
+                if (!targetLocation.delete()) {
+                    throw new RuntimeException("File Overwrite Failed: " + targetLocation.getPath());
+                }
+            }
+            if (!generatedFile.renameTo(targetLocation)) {
+                throw new RuntimeException("Rename Failed: " + targetLocation.getPath());
+            }
+        }
+
+        if (!genDir.delete()) {
+            throw new RuntimeException("Failed to delete directory: " + genDir.getPath());
+        }
+    }
+
     /**
      * This class builds {@link Thrift} instances.
      *

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

+package org.apache.thrift.maven;
+
+import org.codehaus.plexus.util.FileUtils;
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Test;
+import static org.junit.Assert.*;
+
+import java.io.File;
+
+public class TestThrift {
+
+    private File testRootDir;
+    private File testResourceDir;
+
+    @Before
+    public void setup() throws Exception {
+        final File tmpDir = new File(System.getProperty("java.io.tmpdir"));
+        testRootDir = new File(tmpDir, "thrift-test");
+
+        if (testRootDir.exists()) {
+            FileUtils.cleanDirectory(testRootDir);
+        } else {
+            assertTrue("Failed to create output directory for test: "+ testRootDir.getPath(), testRootDir.mkdir());
+        }
+
+        testResourceDir = new File("src/test/resources");
+        assertTrue("Unable to find test resources", testRootDir.exists());
+    }
+
+    @Test
+    public void testThriftCompile() throws Exception {
+        final File idlDir = new File(testResourceDir, "idl");
+        final File genJavaDir = new File(testRootDir, Thrift.GENERATED_JAVA);
+        final File thriftFile = new File(idlDir, "shared.thrift");
+
+        Thrift.Builder builder = new Thrift.Builder("thrift", testRootDir);
+        builder.addThriftPathElement(idlDir);
+        builder.addThriftFile(thriftFile);
+
+        final Thrift thrift = builder.build();
+
+        assertTrue("File not found: shared.thrift", thriftFile.exists());
+        assertFalse("gen-java directory should not exist", genJavaDir.exists());
+
+        // execute the compile
+        final int result = thrift.compile();
+        assertEquals(0, result);
+
+        assertFalse("gen-java directory was not removed", genJavaDir.exists());
+        assertTrue("generated java code doesn't exist",
+            new File(testRootDir, "shared/SharedService.java").exists());
+    }
+
+    @After
+    public void cleanup() throws Exception {
+        if (testRootDir.exists()) {
+            FileUtils.cleanDirectory(testRootDir);
+            assertTrue("Failed to delete output directory for test: "+ testRootDir.getPath(), testRootDir.delete());
+        }
+    }
+}

src/test/resources/idl/shared.thrift

+/*
+ * 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.
+ */
+
+/**
+ * This Thrift file can be included by other Thrift files that want to share
+ * these definitions.
+ */
+
+namespace cpp shared
+namespace java shared
+namespace perl shared
+
+struct SharedStruct {
+  1: i32 key
+  2: string value
+}
+
+service SharedService {
+  SharedStruct getStruct(1: i32 key)
+}