protected static String unescapeJava()

in src/main/java/org/apache/commons/configuration2/PropertiesConfiguration.java [1151:1231]
67 lines of code
18 McCabe index (conditional complexity)

    protected static String unescapeJava(final String str, final boolean jupCompatible) {
        if (str == null) {
            return null;
        }
        final int sz = str.length();
        final StringBuilder out = new StringBuilder(sz);
        final StringBuilder unicode = new StringBuilder(UNICODE_LEN);
        boolean hadSlash = false;
        boolean inUnicode = false;
        for (int i = 0; i < sz; i++) {
            final char ch = str.charAt(i);
            if (inUnicode) {
                // if in unicode, then we're reading unicode
                // values in somehow
                unicode.append(ch);
                if (unicode.length() == UNICODE_LEN) {
                    // unicode now contains the four hex digits
                    // which represents our unicode character
                    try {
                        final int value = Integer.parseInt(unicode.toString(), HEX_RADIX);
                        out.append((char) value);
                        unicode.setLength(0);
                        inUnicode = false;
                        hadSlash = false;
                    } catch (final NumberFormatException nfe) {
                        throw new ConfigurationRuntimeException("Unable to parse unicode value: " + unicode, nfe);
                    }
                }
                continue;
            }

            if (hadSlash) {
                // handle an escaped value
                hadSlash = false;

                switch (ch) {
                case 'r':
                    out.append('\r');
                    break;
                case 'f':
                    out.append('\f');
                    break;
                case 't':
                    out.append('\t');
                    break;
                case 'n':
                    out.append('\n');
                    break;
                default:
                    if (!jupCompatible && ch == 'b') {
                        out.append('\b');
                    } else if (ch == 'u') {
                        // uh-oh, we're in unicode country....
                        inUnicode = true;
                    } else {
                        // JUP simply throws away the \ of unknown escape sequences
                        if (!needsUnescape(ch) && !jupCompatible) {
                            out.append('\\');
                        }
                        out.append(ch);
                    }
                    break;
                }

                continue;
            }
            if (ch == '\\') {
                hadSlash = true;
                continue;
            }
            out.append(ch);
        }

        if (hadSlash) {
            // then we're in the weird case of a \ at the end of the
            // string, let's output it anyway.
            out.append('\\');
        }

        return out.toString();
    }