add paremeter to configure javac feature --enable-preview (#199)

Signed-off-by: Olivier Lamy <olamy@apache.org>

Author: olamy

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

@@ -178,6 +178,11 @@ public class CompilerConfiguration
      */
     private String debugFileName;
 
+    /**
+     * configure <code>--enable-preview</code> of java compiler
+     */
+    private boolean enablePreview;
+
     // ----------------------------------------------------------------------
     //
     // ----------------------------------------------------------------------
@@ -632,6 +637,16 @@ public void setParameters(boolean parameters)
         this.parameters = parameters;
     }
 
+    public boolean isEnablePreview()
+    {
+        return enablePreview;
+    }
+
+    public void setEnablePreview(boolean enablePreview)
+    {
+        this.enablePreview = enablePreview;
+    }
+
     public void setProc(String proc )
     {
         this.proc = proc;

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

@@ -332,6 +332,11 @@ public static String[] buildCompilerArguments( CompilerConfiguration config, Str
             args.add( "-parameters" );
         }
 
+        if ( config.isEnablePreview() )
+        {
+            args.add( "--enable-preview" );
+        }
+
         if ( config.isShowDeprecation() )
         {
             args.add( "-deprecation" );