The principles and design ideas of the SBE framework in the Java library
SBE (Simple Binary Encoding) framework is a Java class library for solving high -performance message codec requirements.Its design idea is to improve the performance and scalability of the system through the efficient coding and decoding of the message format.
The core principle of the SBE framework is to use template -based code generation technology to generate the corresponding Java class according to the pre -defined message mode.These Java classes are responsible for converting message data into binary formats and decoding binary data into readable message formats.The code generator of the SBE framework uses XML files to describe the message mode, which contains information such as the type, length, and order of the message field.
Below is an example of using the SBE framework for message codec:
First, we need to define a XML file to describe the message mode.Suppose we want to define a simple exchange order message, including the order ID, the exchange code, the direction and quantity of the sale and the quantity.We can create a file called "Order.xml" and define the message structure and field information in it:
<message>
<name>Order</name>
<description> Exchange order message </description>
<field>
<name>orderId</name>
<type>uint64</type>
<description> Order ID </description>
</field>
<field>
<name>exchangeCode</name>
<type>string</type>
<length>8</length>
<description> Exchange code </description>
</field>
<field>
<name>side</name>
<type>enum</type>
<semanticType>Side</semanticType>
<description> buying and selling direction </description>
<enum>
<validValue>buy</validValue>
<validValue>sell</validValue>
</enum>
</field>
<field>
<name>quantity</name>
<type>uint32</type>
<description>数量</description>
</field>
</message>
Next, we can use the code generator provided by the SBE framework to convert this XML file into a Java class.Execute the following commands in the command line:
bash
java -jar sbe.jar order.xml java
The generated Java code will contain a class called "Order", which provides a series of methods to encode and decoding order messages.We can use these methods to operate order data.
import org.example.messages.*;
import org.agrona.DirectBuffer;
// Create the ORDER object
Order order = new Order();
order.setOrderId(1234567890);
order.setExchangeCode("ABC");
order.setSide(SideEnum.BUY);
order.setQuantity(100);
// Code order message is byte array
byte[] encodedData = new byte[order.sbeEncodedLength()];
order.encode(new UnsafeBuffer(encodedData), 0);
// Send the encoded byte array to the network or storage device
// After receiving the byte array, the decoding is the order message
Order receivedOrder = new Order();
receivedOrder.decode(new UnsafeBuffer(encodedData), 0);
// Use the decoding order message for business operation
System.out.println("Received Order ID: " + receivedOrder.getOrderId());
System.out.println("Received Exchange Code: " + receivedOrder.getExchangeCode());
System.out.println("Received Side: " + receivedOrder.getSide());
System.out.println("Received Quantity: " + receivedOrder.getQuantity());
Through the above examples, we can see that the SBE framework simplifies the encoding and decoding process of the message.Using the Java class generated by SBE, we can easily convert message data into binary formats, and decoding binary data into readable message formats when needed to achieve high -performance message processing.
