Add the ability to specify --module-version argument for Java 9+ (#42)

Author: plamentotev

plexus-compiler-api/src/main/java/org/codehaus/plexus/compiler/CompilerConfiguration.java

@@ -87,6 +87,11 @@ public class CompilerConfiguration
 
     private String sourceEncoding;
 
+    /**
+     * value of --module-version parameter in java 9+
+     */
+    private String moduleVersion;
+
     private Collection<Map.Entry<String,String>> customCompilerArguments = new ArrayList<Map.Entry<String,String>>();
 
     private boolean fork;
@@ -404,6 +409,16 @@ public void setSourceEncoding( String sourceEncoding )
         this.sourceEncoding = sourceEncoding;
     }
 
+    public String getModuleVersion()
+    {
+        return moduleVersion;
+    }
+
+    public void setModuleVersion( String moduleVersion )
+    {
+        this.moduleVersion = moduleVersion;
+    }
+
     public void addCompilerCustomArgument( String customArgument, String value )
     {
         customCompilerArguments.add( new AbstractMap.SimpleImmutableEntry<String, String>( customArgument, value ) );

plexus-compilers/plexus-compiler-javac/src/main/java/org/codehaus/plexus/compiler/javac/JavacCompiler.java

@@ -372,6 +372,12 @@ else if ( !suppressSource( config ) )
             args.add( config.getSourceEncoding() );
         }
 
+        if ( !StringUtils.isEmpty( config.getModuleVersion() ) )
+        {
+            args.add( "--module-version" );
+            args.add( config.getModuleVersion() );
+        }
+
         for ( Map.Entry<String, String> entry : config.getCustomCompilerArgumentsEntries() )
         {
             String key = entry.getKey();

plexus-compilers/plexus-compiler-javac/src/test/java/org/codehaus/plexus/compiler/javac/AbstractJavacCompilerTest.java

@@ -243,6 +243,31 @@ public void testModulePath() throws Exception
         internalTest( compilerConfiguration, expectedArguments );
     }
 
+    public void testModuleVersion()
+    {
+        List<String> expectedArguments = new ArrayList<String>();
+
+        CompilerConfiguration compilerConfiguration = new CompilerConfiguration();
+
+        // outputLocation
+        compilerConfiguration.setOutputLocation( "/output" );
+        expectedArguments.add( "-d" );
+        expectedArguments.add( new File( "/output" ).getAbsolutePath() );
+
+        // default source + target
+        expectedArguments.add( "-target" );
+        expectedArguments.add( "1.1" );
+        expectedArguments.add( "-source" );
+        expectedArguments.add( "1.3" );
+
+        // module version
+        compilerConfiguration.setModuleVersion( "1.2.0-SNAPSHOT" );
+        expectedArguments.add( "--module-version" );
+        expectedArguments.add( "1.2.0-SNAPSHOT" );
+
+        internalTest( compilerConfiguration, expectedArguments );
+    }
+
     public void testReleaseVersion()
     {
         List<String> expectedArguments = new ArrayList<String>();