public String getRelativeName()

in commons-vfs2/src/main/java/org/apache/commons/vfs2/provider/AbstractFileName.java [315:363]
34 lines of code
15 McCabe index (conditional complexity)

    public String getRelativeName(final FileName name) throws FileSystemException {
        final String path = name.getPath();

        // Calculate the common prefix
        final int basePathLen = getPath().length();
        final int pathLen = path.length();

        // Deal with root
        if (basePathLen == 1 && pathLen == 1) {
            return ".";
        }
        if (basePathLen == 1) {
            return path.substring(1);
        }

        final int maxlen = Math.min(basePathLen, pathLen);
        int pos = 0;
        while (pos < maxlen && getPath().charAt(pos) == path.charAt(pos)) {
            pos++;
        }

        if (pos == basePathLen && pos == pathLen) {
            // Same names
            return ".";
        }
        if (pos == basePathLen && pos < pathLen && path.charAt(pos) == SEPARATOR_CHAR) {
            // A descendent of the base path
            return path.substring(pos + 1);
        }

        // Strip the common prefix off the path
        final StringBuilder buffer = new StringBuilder();
        if (pathLen > 1 && (pos < pathLen || getPath().charAt(pos) != SEPARATOR_CHAR)) {
            // Not a direct ancestor, need to back up
            pos = getPath().lastIndexOf(SEPARATOR_CHAR, pos);
            buffer.append(path.substring(pos));
        }

        // Prepend a '../' for each element in the base path past the common
        // prefix
        buffer.insert(0, "..");
        pos = getPath().indexOf(SEPARATOR_CHAR, pos + 1);
        while (pos != -1) {
            buffer.insert(0, "../");
            pos = getPath().indexOf(SEPARATOR_CHAR, pos + 1);
        }

        return buffer.toString();
    }