yuicompress.js

var YUIC = com.yahoo.platform.yui.compressor;
var YUIJ = com.yahoo.platform.yui.org.mozilla.javascript;

var fakeOutStream = new Packages.java.io.Writer({
   data: [],
   write : function(text) { this.data.push(text);},
   readAll : function() { return this.data.join("\n\n");},
});

var errorReporter = new YUIJ.ErrorReporter({
   warning: function(message, sourceName, line, lineSource, lineOffset) {
      //error("WARN " + message);
   },
   error: function(message, sourceName, line, lineSource, lineOffset) {
      //error("ERROR " + message);
   },
   runtimeError : function(message, sourceName, line, lineSource, lineOffset) {
      fatal("YuiCompressor._compress", "JavaScript compilation error in " + sourceName + ", " + message);
   },
});

var inFileSuccess = fileSet.ins.every(function(inFile) {
   var inputFilename = YuiCompressor.STATIC_DIR + inFile;
   var sourceCharset = app.properties.sourceCharset || "ISO-8859-15";
   try { 
      var inStream = new Packages.java.io.InputStreamReader(new Packages.java.io.FileInputStream(inputFilename), sourceCharset);
   } catch (e) {
      error("YuiCompressor._compresss", "Can't open input " + inFile + " of " + fileSet.title, e);
      return false;
   }
   if (fileSet.type === "js") {
      var jsCompressor = new YUIC.JavaScriptCompressor(inStream, errorReporter);
      // linebreak, munge, verbose, preserverAllSemis, disableOptimize
      jsCompressor.compress(fakeOutStream, 80, true, true, true, true);
   } else if (fileSet.type === "css") {
      var cssCompressor = new YUIC.CssCompressor(inStream);
      cssCompressor.compress(fakeOutStream, 80);
   } else {
      error("YuiCompressor._compress", "Unknown filetype, canceling. fileSet " + fileSet.title);
      return false;
   }
   inStream.close();
   return true;
}, this);

var outFileSuccess = false;
if (inFileSuccess) {   
   var dataCompressed = fakeOutStream.readAll();
   var outFilename = YuiCompressor.STATIC_DIR + fileSet.out;
   var outStream = new helma.File(outFilename);
   outStream.remove();
   outStream.open();
   // helma.File doesn't throw exceptions
   outFileSuccess = outStream.write(dataCompressed);
   if (outFileSuccess == false) {
      fatal("YuiCompressor._compress", "Can't write output " + outFilename);
   }
   outStream.flush();
   outStream.close();
}
return inFileSuccess && outFileSuccess;

ah, nice :)

I just ripped this out of our helma code :) might be useful.. the java API has zero documentation

google closure compiler java api is fully documented, but complex as hell:
http://closure-compiler.googlecode.com/svn/trunk/javadoc/index.html

... and like yuicompiler it comes with its own rhino.