What is the purpose of CSSEngine class in batik css parser

Question

I am evaluating batik css parser to integrate it with our product. To use it best I want to understand what all it's classes represent. I can not understand the purpose of the org.apache.batik.css.engine.CSSEngine class. What is this class used for?

Answer 1

CSSEngine class has a function parseStyleSheet which returns a StyleSheet object. This StyleSheet object is actually a dom representation of the css.

StyleSheet ss = cssEngine.parseStyleSheet(new ParsedURL("file:///"+filename),"max-width: 800px");

You can create your own cssengine by extending CSSEngine class.

  public class MyCSSEngine extends CSSEngine{

         public MyCSSEngine (ExtendedParser parser) {

        super(null, null, parser, MY_VALUE_MANAGERS, SVGCSSEngine.SVG_SHORTHAND_MANAGERS, null, null, "style",
                  null,
                  "class",
                  true,
                  null,
                  new MyCSSContext());
        // TODO Auto-generated constructor stub
    }
}

create MyCSSContext by extending org.apache.batik.css.engine.CSSContext. Coming to MY_VALUE_MANAGERS which is important. Value manger can be like

public static final ValueManager[] MY_VALUE_MANAGERS = {
    new AlignmentBaselineManager(),
    new BaselineShiftManager(),
    new ClipManager(),
    new ClipPathManager(),
    new ClipRuleManager(),

    new ColorManager(),
    new ColorInterpolationManager(),
    new ColorInterpolationFiltersManager(),
    new ColorProfileManager(),
    new ColorRenderingManager()
}

It basically register the property you are interested in while parsing.(Its much more than that).

You can also use org.apache.batik.css.engine.SVGCSSEngine.SVG_VALUE_MANAGERS but implementing own value manager gives you power to handle your own custom css property like

-my-own-color:mufunc(10,23,45)