Question

I’m trying to write a function like:

public Map<String, Document> getTestXml(JarFile jarFile) {
    Map<String, Document> result = Maps.newHashMap();

    Enumeration<JarEntry> jarEntries = jarFile.getEntries();
    while (jarEntries.hasMoreElements()) {
        JarEntry jarEntry = jarEntries.nextElement();

        String name = jarEntry.getName();
        if (name.endsWith(".class") && !name.contains("$")) {
            String testClassName = name.replace(".class", "").replace("/", ".");
            String testXmlFilename = "TEST-" + testClassName + ".xml";

            InputStream testXmlInputStream = testJarFile.getInputStream(
                    testJarFile.getJarEntry(testXmlFilename));

            DocumentBuilderFactory documentBuilderFactory = DocumentBuilderFactory.newInstance();
            DocumentBuilder documentBuilder = documentBuilderFactory.newDocumentBuilder();
            Document testXmlDocument = documentBuilder.parse(testXmlInputStream);

            result.put(testClassName, testXmlDocument);
        }
    }

    return result;
}

And I would like to write a unit test that doesn’t actually create a JarFile on the file system. I’ve tried to look for how to create a File object in memory, but haven’t found anything like that. Anyone have any suggestions?

Answer 1

Instead of a JarFile, use a JarInputStream. For testing, hook the JarInputStream up to a ByteArrayInputStream loaded with in-memory jar data, and in normal operation hook it up to the input stream from a file.