public ByteBuffer encode()

in coap/src/main/java/org/apache/mina/coap/codec/CoapEncoder.java [56:144]
62 lines of code
17 McCabe index (conditional complexity)

    public ByteBuffer encode(CoapMessage message, Void context) {

        LOG.debug("encoding {}", message);

        // compute size of the needed buffer
        int size = HEADER_SIZE + message.getToken().length;

        int delta = 0;
        for (CoapOption opt : message.getOptions()) {
            // compute delta encoding size
            int code = opt.getType().getCode();
            delta = code - delta;
            if (delta < 13) {
                size += 1;
            } else if (delta < 256 + 13) {
                size += 2;
            } else if (delta < 65536 + 269) {
                size += 3;
            }

            // compute option length encoding size
            int optLength = opt.getData().length;
            if (optLength < 13) {
                size += 0;
            } else if (optLength < 256 + 13) {
                size += 1;
            } else if (optLength < 65536 + 269) {
                size += 2;
            }

            // compute option data encoding size
            size += optLength;
        }

        // if we have a payload, we place the marker and the payload
        if (message.getPayload() != null && message.getPayload().length > 0) {
            // payload marker
            size += 1;
            size += message.getPayload().length;
        }

        ByteBuffer buffer = ByteBuffer.allocate(size);

        buffer.order(ByteOrder.BIG_ENDIAN);

        // encode header
        buffer.put((byte) (((message.getVersion() & 0x03) << 6) | (message.getType().getCode() & 0x03) << 4 | (message
                .getToken().length & 0x0F)));
        buffer.put((byte) message.getCode());
        buffer.putShort((short) message.getId());
        buffer.put(message.getToken());

        // encode options
        int lastOptCode = 0;

        for (CoapOption opt : message.getOptions()) {
            int optionDelta = opt.getType().getCode() - lastOptCode;
            int deltaQuartet = getQuartet(optionDelta);
            int optionLength = opt.getData().length;

            int optionQuartet = getQuartet(optionLength);

            buffer.put((byte) ((deltaQuartet << 4) | optionQuartet));

            // write extended option delta field (0 - 2 bytes)
            if (deltaQuartet == 13) {
                buffer.put((byte) (optionDelta - 13));
            } else if (deltaQuartet == 14) {
                buffer.putShort((short) (optionDelta - 269));
            }

            if (optionQuartet == 13) {
                buffer.put((byte) (optionLength - 13));
            } else if (optionQuartet == 14) {
                buffer.putShort((short) (optionLength - 269));
            }
            buffer.put(opt.getData());

            lastOptCode = opt.getType().getCode();
        }

        if (message.getPayload() != null && message.getPayload().length > 0) {
            buffer.put((byte) 0xFF);
            buffer.put(message.getPayload());
        }

        buffer.flip();
        return buffer;
    }