How to build javadoc from sources within a .jar file?

Question

I have to build Javadoc from myCode.jar that contains both sources and class files. Can I do it without extracting the jar?

According to http://java.sun.com/

Answer 1

Some first tests indicate it does not work (at least on OpenJDK 1.6.0_20, which I have here).

So, I looked into the source (browsable in a mercurial web-interface). Javadoc (in the version there, which may differ from the one I have here) uses quite some bits of Javac in its for the operation, and it looks like both are using the javax.tools.JavaFileManager interface to implement access to their source files, specifically in the subinterface StandardJavaFileManager.

This interface claims to be able to access zip file entries:

This file manager creates file objects representing regular files, zip file entries, or entries in similar file system based containers.

But here how it is used (in JavaDocTool.getRootDocImpl()):

  148                 String name = it.head;
  149                 if (!docClasses && name.endsWith(".java") && new File(name).exists()) {
  150                     JavaFileObject fo = fm.getJavaFileObjects(name).iterator().next();
  151                     docenv.notice("main.Loading_source_file", name);
  152                     JCCompilationUnit tree = parse(fo);
  153                     classTrees.append(tree);
  154                 } else if (isValidPackageName(name)) {
  155                     names = names.append(name);
  156                 } else if (name.endsWith(".java")) {
  157                     docenv.error(null, "main.file_not_found", name);
  158                 } else {
  159                     docenv.error(null, "main.illegal_package_name", name);
  160                 }

The first case would apply in your call with a .java file - but since it does not exist as a file in the file system (new File(name).exists() returns false), this does not help, and you get instead the third case with a "file not found" error.

It looks like it could work when replacing this condition with a more suitable one (like !fm.getJavaFileObjects(name).isEmpty() - provided the context is initialized with a JavaFileManager which in fact looks in jar/zip files, which I did not check now.

So, you'll have either to unpack your source jar, or patch your javac implementation (preferably contributing this to the main javac source).