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javaeclipsewarningsrhino

Eclipse: Custom warnings (Rhino String params)

Is there a way to define a custom warning in Eclipse? How?

My motivation

I have a Large Number of classes that are exposed as JavaScript objects via Mozilla Rhino. I've run across a couple bugs like this:

public void jsFunction_foo(String bar) {
  if (bar != null) {
    ...
  } else {
    ...
  }
}

The Bug: A String parameter in a jsFunction_ IS NEVER NULL. If the JavaScript calls foo(null), the parameter that arrives is "null", not null. HUGE difference.

The solution is to declare the parameter as Scriptable, and then convert it if present:

public void jsFunction_foo(Scriptable bar) {
  if (bar != null) {
    String barStr = convertToString(bar);
    ...
  } else {
    ...
  }
}

So anyway. We have 50+ classes we expose in JavaScript. Rather than schlepping through them all by hand, I'd like to automate the process. Something like:

if (function.name.indexOf("jsFunction_") == 0 &&
    function.paramTypes.contains(String.class) &&
    stringParamComparedToNull(function))
  addWarning(function.lineNum, "It doesn't work like that!");

Ideally this custom warning would be shared across my team (or even with the Mozilla Rhino project itself) so other folks won't keep making the same mistakes.

A way to crash Eclipse for people that compare to "null" would be good too. Grr.

Solution

  • You can use PMD to define a custom rule using variant of XPath over the Java code. PMD also has Eclipse plugin.