!7

sclass ShowJDKClass extends DynModule {
  S file, text;
  
  transient SingleComponentPanel scp;
  
  JComponent visualize() { scp = singleComponentPanel(); updateVis(); ret scp; }
  void unvisualize() { scp = null; }

  start { dm_onTopInput(r updateMe); }
  
  void update {
    S s = dm_getInterestingString();
    if (isIdentifier(s)) {
      S file = first(endingWithIC(allJDKSourceFileNames(), "/" + s + ".java"));
      if (file == null) ret;
      if (!setField(+file)) ret;
      setField(text := loadTextFileFromZip(jdkSrcZip(), file));
      setModuleName(file);
      updateVis();
    }
  }

  void updateVis {
    if (scp != null) scp.setComponent(scrollableJavaxSyntaxTextAreaOrNull(text));
  }
}

Began life as a copy of #1015869