public static SimpleFilter parse()

in subsystem/subsystem-core/src/main/java/org/apache/aries/subsystem/core/capabilityset/SimpleFilter.java [165:280]
108 lines of code
25 McCabe index (conditional complexity)

    public static SimpleFilter parse(String filter)
    {
        int idx = skipWhitespace(filter, 0);

        if ((filter == null) || (filter.length() == 0) || (idx >= filter.length()))
        {
            throw new IllegalArgumentException("Null or empty filter.");
        }
        else if (filter.charAt(idx) != '(')
        {
            throw new IllegalArgumentException("Missing opening parenthesis: " + filter);
        }

        SimpleFilter sf = null;
        List stack = new ArrayList();
        boolean isEscaped = false;
        while (idx < filter.length())
        {
            if (sf != null)
            {
                throw new IllegalArgumentException(
                    "Only one top-level operation allowed: " + filter);
            }

            if (!isEscaped && (filter.charAt(idx) == '('))
            {
                // Skip paren and following whitespace.
                idx = skipWhitespace(filter, idx + 1);

                if (filter.charAt(idx) == '&')
                {
                    int peek = skipWhitespace(filter, idx + 1);
                    if (filter.charAt(peek) == '(')
                    {
                        idx = peek - 1;
                        stack.add(0, new SimpleFilter(null, new ArrayList(), SimpleFilter.AND));
                    }
                    else
                    {
                        stack.add(0, new Integer(idx));
                    }
                }
                else if (filter.charAt(idx) == '|')
                {
                    int peek = skipWhitespace(filter, idx + 1);
                    if (filter.charAt(peek) == '(')
                    {
                        idx = peek - 1;
                        stack.add(0, new SimpleFilter(null, new ArrayList(), SimpleFilter.OR));
                    }
                    else
                    {
                        stack.add(0, new Integer(idx));
                    }
                }
                else if (filter.charAt(idx) == '!')
                {
                    int peek = skipWhitespace(filter, idx + 1);
                    if (filter.charAt(peek) == '(')
                    {
                        idx = peek - 1;
                        stack.add(0, new SimpleFilter(null, new ArrayList(), SimpleFilter.NOT));
                    }
                    else
                    {
                        stack.add(0, new Integer(idx));
                    }
                }
                else
                {
                    stack.add(0, new Integer(idx));
                }
            }
            else if (!isEscaped && (filter.charAt(idx) == ')'))
            {
                Object top = stack.remove(0);
                if (top instanceof SimpleFilter)
                {
                    if (!stack.isEmpty() && (stack.get(0) instanceof SimpleFilter))
                    {
                        ((List) ((SimpleFilter) stack.get(0)).m_value).add(top);
                    }
                    else
                    {
                        sf = (SimpleFilter) top;
                    }
                }
                else if (!stack.isEmpty() && (stack.get(0) instanceof SimpleFilter))
                {
                    ((List) ((SimpleFilter) stack.get(0)).m_value).add(
                        SimpleFilter.subfilter(filter, ((Integer) top).intValue(), idx));
                }
                else
                {
                    sf = SimpleFilter.subfilter(filter, ((Integer) top).intValue(), idx);
                }
            }
            else if (!isEscaped && (filter.charAt(idx) == '\\'))
            {
                isEscaped = true;
            }
            else
            {
                isEscaped = false;
            }

            idx = skipWhitespace(filter, idx + 1);
        }

        if (sf == null)
        {
            throw new IllegalArgumentException("Missing closing parenthesis: " + filter);
        }

        return sf;
    }