protected List parseHeaderValue()

in aws-serverless-java-container-core/src/main/java/com/amazonaws/serverless/proxy/internal/servlet/AwsHttpServletRequest.java [656:725]
52 lines of code
13 McCabe index (conditional complexity)

    protected List<HeaderValue> parseHeaderValue(String headerValue, String valueSeparator, String qualifierSeparator) {
        // Accept: text/html, application/xhtml+xml, application/xml;q=0.9, */*;q=0.8
        // Accept-Language: fr-CH, fr;q=0.9, en;q=0.8, de;q=0.7, *;q=0.5
        // Cookie: name=value; name2=value2; name3=value3
        // X-Custom-Header: YQ==

        List<HeaderValue> values = new ArrayList<>();
        if (headerValue == null) {
            return values;
        }

        for (String curValue : headerValue.split(valueSeparator)) {
            float curPreference = 1.0f;
            HeaderValue newValue = new HeaderValue();
            newValue.setRawValue(curValue);

            for (String q : curValue.split(qualifierSeparator)) {

                String[] kv = q.split(HEADER_KEY_VALUE_SEPARATOR, 2);
                String key = null;
                String val = null;
                // no separator, set the value only
                if (kv.length == 1) {
                    val = q.trim();
                }
                // we have a separator
                if (kv.length == 2) {
                    // if the length of the value is 0 we assume that we are looking at a
                    // base64 encoded value with padding so we just set the value. This is because
                    // we assume that empty values in a key/value pair will contain at least a white space
                    if (kv[1].isEmpty()) {
                        val = q.trim();
                    }
                    // this was a base64 string with an additional = for padding, set the value only
                    if ("=".equals(kv[1].trim())) {
                        val = q.trim();
                    } else { // it's a proper key/value set both
                        key = kv[0].trim();
                        val = ("".equals(kv[1].trim()) ? null : kv[1].trim());
                    }
                }

                if (newValue.getValue() == null) {
                    newValue.setKey(key);
                    newValue.setValue(val);
                } else {
                    // special case for quality q=
                    if ("q".equals(key)) {
                        curPreference = Float.parseFloat(val);
                    } else {
                        newValue.addAttribute(key, val);
                    }
                }
            }
            newValue.setPriority(curPreference);
            values.add(newValue);
        }

        // sort list by preference
        values.sort((HeaderValue first, HeaderValue second) -> {
            if ((first.getPriority() - second.getPriority()) < .001f) {
                return 0;
            }
            if (first.getPriority() < second.getPriority()) {
                return 1;
            }
            return -1;
        });
        return values;
    }