Getting Started

Wisdom offers complete Java API and Wisdom Query Language to develop Complex Event Processing (CEP) applications. Wisdom can be used as a Java library or standalone service. Java library is recommended for testing purposes, small-scale applications and Android applications. If you are developing a resource consuming CEP application, it is recommended to use Wisdom Service. Wisdom Service is the only way to use HTTP Source and Sinks. This section explains how to create a simple CEP application using Wisdom Java API and Wisdom Query.

Requirements

Make sure that you have set up the following softwares in your system before building Wisdom.

Java 11 (or latest)
Apache Maven
Apache Kafka (for functionally auto-scaling deployment)

Installation

Clone Wisdom source code

git clone https://github.com/slgobinath/wisdom.git

Open your terminal and change directory

cd wisdom

Compile and install Wisdom using Apache Maven

mvn clean install

How to use?

Wisdom Java API

Create a new Maven Project in your favorite IDE. We use IntelliJ IDEA throughout this document.

Open the pom.xml file add wisdom-core and optionally logback dependencies as shown below:

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>com.javahelps</groupId>
    <artifactId>wisdom-java-api</artifactId>
    <version>1.0-SNAPSHOT</version>
    <build>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <configuration>
                    <source>11</source>
                    <target>11</target>
                </configuration>
            </plugin>
        </plugins>
    </build>

    <properties>
        <wisdom.version>0.0.1</wisdom.version>
        <logback.version>1.2.3</logback.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>com.javahelps.wisdom</groupId>
            <artifactId>wisdom-core</artifactId>
            <version>${wisdom.version}</version>
        </dependency>

        <dependency>
            <groupId>ch.qos.logback</groupId>
            <artifactId>logback-core</artifactId>
            <version>${logback.version}</version>
        </dependency>

        <dependency>
            <groupId>ch.qos.logback</groupId>
            <artifactId>logback-classic</artifactId>
            <version>${logback.version}</version>
        </dependency>
    </dependencies>

</project>

Create a new Java class com.javahelps.helloworld.javaapi.HelloWorld with the following code.

package com.javahelps.helloworld.javaapi;

import com.javahelps.wisdom.core.WisdomApp;
import com.javahelps.wisdom.core.operator.Operator;
import com.javahelps.wisdom.core.stream.InputHandler;
import com.javahelps.wisdom.core.util.EventGenerator;
import com.javahelps.wisdom.core.util.EventPrinter;

public class HelloWorld {

    public static void main(String[] args) {

        // Create a Wisdom application
        WisdomApp app = new WisdomApp("WisdomApp", "1.0.0");

        // Define streams
        app.defineStream("StockStream");
        app.defineStream("OutputStream");

        // Create a query
        app.defineQuery("FilterQuery")
                .from("StockStream")
                .filter(Operator.EQUALS("symbol", "AMAZON"))
                .select("symbol", "price")
                .insertInto("OutputStream");

        // Add output stream callback
        app.addCallback("OutputStream", EventPrinter::print);

        // Get an input handler
        InputHandler inputHandler = app.getInputHandler("StockStream");

        // Start the application
        app.start();

        // Send three inputs
        inputHandler.send(EventGenerator.generate("symbol", "GOOGLE", "price", 10.5, "volume", 10L));
        inputHandler.send(EventGenerator.generate("symbol", "AMAZON", "price", 20.5, "volume", 20L));
        inputHandler.send(EventGenerator.generate("symbol", "FACEBOOK", "price", 30.5, "volume", 30L));

        // Shutdown the application
        app.shutdown();
    }
}

Above code creates Wisdom application with two streams: StockStream and OutputStream, and a query named FilterQuery. The FilterQuery filters stock events of AMAZON, select symbol and price, and insert them into the OutputStream. InputHandler is used to feed events to a stream and callback is used to receive events from a stream.

Running this code should print an output similar to this:

[Event{timestamp=1524709449322, stream=OutputStream, data={symbol=AMAZON, price=20.5}, expired=false}]

As you can see, above Wisdom app filters events having symbol equal to AMAZON and prints them to the console.

Wisdom Query

Above Wisdom application can be defined using the folloing Wisdom query:

@app(name='WisdomApp', version='1.0.0')
def stream StockStream;
def stream OutputStream;

@query(name='FilterQuery')
from StockStream
filter symbol == 'AMAZON'
select symbol, price
insert into OutputStream;

To use this query in a Java application, create a new Maven project in your favorite IDE.

Open the pom.xml file and add wisdom-core, wisdom-query and optionally logback dependencies as shown below:

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>com.javahelps</groupId>
    <artifactId>wisdom-java-api</artifactId>
    <version>1.0-SNAPSHOT</version>
    <build>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <configuration>
                    <source>11</source>
                    <target>11</target>
                </configuration>
            </plugin>
        </plugins>
    </build>

    <properties>
        <wisdom.version>0.0.1</wisdom.version>
        <logback.version>1.2.3</logback.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>com.javahelps.wisdom</groupId>
            <artifactId>wisdom-core</artifactId>
            <version>${wisdom.version}</version>
        </dependency>

        <dependency>
            <groupId>com.javahelps.wisdom</groupId>
            <artifactId>wisdom-query</artifactId>
            <version>${wisdom.version}</version>
        </dependency>

        <dependency>
            <groupId>ch.qos.logback</groupId>
            <artifactId>logback-core</artifactId>
            <version>${logback.version}</version>
        </dependency>

        <dependency>
            <groupId>ch.qos.logback</groupId>
            <artifactId>logback-classic</artifactId>
            <version>${logback.version}</version>
        </dependency>
    </dependencies>

</project>

Create a new Java class com.javahelps.helloworld.wisdomql.HelloWorld with the following code.

package com.javahelps.helloworld.wisdomql;

import com.javahelps.wisdom.core.WisdomApp;
import com.javahelps.wisdom.core.stream.InputHandler;
import com.javahelps.wisdom.core.util.EventGenerator;
import com.javahelps.wisdom.core.util.EventPrinter;
import com.javahelps.wisdom.query.WisdomCompiler;

public class HelloWorld {

    public static void main(String[] args) {

        String query = "@app(name='WisdomApp', version='1.0.0') " +
                "def stream StockStream; " +
                "def stream OutputStream; " +
                " " +
                "@query(name='FilterQuery') " +
                "from StockStream " +
                "filter symbol == 'AMAZON' " +
                "select symbol, price " +
                "insert into OutputStream;";

        // Create a Wisdom application
        WisdomApp app = WisdomCompiler.parse(query);

        // Add output stream callback
        app.addCallback("OutputStream", EventPrinter::print);

        // Get an input handler
        InputHandler inputHandler = app.getInputHandler("StockStream");

        // Start the application
        app.start();

        // Send three inputs
        inputHandler.send(EventGenerator.generate("symbol", "GOOGLE", "price", 10.5, "volume", 10L));
        inputHandler.send(EventGenerator.generate("symbol", "AMAZON", "price", 20.5, "volume", 20L));
        inputHandler.send(EventGenerator.generate("symbol", "FACEBOOK", "price", 30.5, "volume", 30L));

        // Shutdown the application
        app.shutdown();
    }
}

Above code replaces the Java API used in previous example by the Wisdom query to construct a Wisdom app. Once the Wisdom app is created, creating InputHandler and sending events are same as the previous example.