public void parse()

in jackrabbit-jcr-commons/src/main/java/org/apache/jackrabbit/commons/json/JsonParser.java [81:188]
90 lines of code
30 McCabe index (conditional complexity)

    public void parse(Reader reader) throws IOException {

        //StringBuffer key = new StringBuffer();
        StringBuffer value = new StringBuffer();

        int state;
        Stack complexVStack = new Stack();

        int next = reader.read();
        if (next == '{') {
            handler.object();
            complexVStack.push(OBJECT);
            state = KEY_START;
            next = readIgnoreWhitespace(reader);
        } else {
            throw new IOException("JSON object must start with a '{'");
        }


        while (next != EOF) {
            switch (state) {

                case KEY_START:
                    if (next == '"') {
                        String key = nextString(reader, '\"');
                        next = readIgnoreWhitespace(reader);
                        if (next == ':') {
                            handler.key(key);
                            state = VALUE_START;
                        } else {
                            throw new IOException("Key-Value pairs must be separated by ':'");
                        }
                        next = readIgnoreWhitespace(reader);
                    } else if (next == '}') {
                        // empty object
                        state = VALUE;
                    } else {
                        throw new IOException("Key must be in String format (double quotes)");
                    }
                    break;

                case VALUE_START:
                    if (next == '[') {
                        handler.array();
                        complexVStack.push(ARRAY);
                        // status still value_start
                        next = readIgnoreWhitespace(reader);
                    } else if (next == '{') {
                        handler.object();
                        complexVStack.push(OBJECT);
                        state = KEY_START;
                        next = readIgnoreWhitespace(reader);
                    } else if (next == '\"') {
                        handler.value(nextString(reader, '\"'));
                        next = readIgnoreWhitespace(reader);
                        if (!(next == ',' || next == ']' || next == '}')) {
                            throw new IOException("Invalid json format");
                        }
                    } else {
                        // start of boolean/long/double/null value
                        // will be notified as key-value pair
                        state = VALUE;
                    }
                    break;

                case VALUE:
                    if (next == '"') {
                        throw new IOException("Invalid json format");
                    } else if (next == ',') {
                        state = (complexVStack.peek() == OBJECT) ? KEY_START : VALUE_START;
                        value = resetValue(value);
                        next = readIgnoreWhitespace(reader);
                    } else if (next == ']') {
                        if (complexVStack.pop() != ARRAY) {
                            throw new IOException("Invalid json format: Unexpected array termination.");
                        }
                        value = resetValue(value);
                        handler.endArray();

                        next = readIgnoreWhitespace(reader);
                        if (!(next == ',' || next == '}' || next == ']')) {
                            throw new IOException("Invalid json format");
                        }
                    } else if (next == '}') {
                        if (complexVStack.pop() != OBJECT) {
                            throw new IOException("Invalid json format: Unexpected object termination.");
                        }
                        value = resetValue(value);
                        handler.endObject();

                        next = readIgnoreWhitespace(reader);
                        if (!(next == ',' || next == '}' || next == ']' || next == EOF)) {
                            throw new IOException("Invalid json format");
                        }
                    } else {
                        // simple value
                        value.append((char) next);
                        next = reader.read();
                    }
                    break;
            }
        }

        // EOF reached -> minimal validation check
        if (value.length() != 0) {
            throw new IOException("Invalid json format");
        }
    }