java2groovy [file ...]

Description:
    The java2groovy tool reads class and interface definitions, written in the
    Java programming language, and converts them into groovy source files.

• I took the original java.g grammar which groovy.g is based upon
• amended it to remove Java features not implemented in groovy.g ("do" keyword, Array Initialisers etc)
• Created a Java2GroovyMain which takes Java files and parses into a Java like source AST
• Converted the Java like source AST into a one for one Groovy equivalant
• Applied a Groovifier, which applies common simplification tasks to the AST (e.g. don't need public keyword if you have other modifiers)
• Then the resultant groovy AST is output using the "pretty printer"

So... job done, what's next :-)

Seriously though...

• java.g needs to be amended some more to use create() instead of #[], otherwise line/col nums are lost
• Groovifier.java is an interesting step, lots of tiny refactorings, at the source AST level, very powerful...

  //----
  // (e.g. don't need public keyword if you have other modifiers)
  //
  if (t.getType() == MODIFIERS) {
     GroovySourceAST publicNode = t.childOfType(LITERAL_public);
         if (t.getNumberOfChildren() > 1 && publicNode != null) {
         // has more than one modifier, and one of them is public
             // delete 'public' node
             publicNode.setType(EXPR);
  }
  //----
  

• some minor changes to things like string literals (get a double double-quote each time at mo...)
• all pretty printer issues apply (no comments on AST etc)

Oh yes... a sample...

$ java2groovy src/test/groovy/lang/MockWriter.java

/*
 Automatically Converted from Java Source

 by java2groovy v0.0.1   Copyright Jeremy Rayner 2007

 !! NOT FIT FOR ANY PURPOSE !!
 'java2groovy' cannot be used to convert one working program into another
*/

package groovy.lang
class MockWriter

   {

   private String output

   String getOutput() {
       String answer = output
       output = null
       return answer
   }


   void setOutput(String
        output) {
   }


   void println() {
       setOutput(""println()"")
   }


   void println(Object
        object) {
       setOutput(""println("" + object + "")"")
   }


   void print(Object
        object) {
       setOutput(""print("" + object + "")"")
   }
}