This tutorial shows you how to create a simple ‘Hello World’ example in Apache Ignite.
The following technologies were used in this example:
- Java Development Kit (JDK) 1.8
- Apache Ignite 1.5.0-b1
- Maven 3.1.1
- IntelliJ IDEA 15 CE
Note: JDK 1.7 or above is required.
1. Download and Install Ignite
Download the latest binary distribution from the Apache Ignite website and extract the resulting .zip file to a location of your choice:
$ unzip apache-ignite-fabric-1.5.0-b1-bin.zip $ cd apache-ignite-fabric-1.5.0-b1-bin
2. Set Environment Variable (this step is optional)
Set IGNITE_HOME environment variable to point to the installation folder and make sure there is no trailing / in the path. On my mac, I have set this environment variable in .bash_profile file, like so:
export IGNITE_HOME=<path-to-ignite-installation-folder>
3. Start Ignite Cluster
Start a node using bin/ignite.sh command and specify an example configuration file provided in the Ignite installation:
$ bin/ignite.sh examples/config/example-ignite.xml
If the installation was successful, your Ignite node startup message should look like this:
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I have started one more node in another terminal, by repeating the above command (in step 3).
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I now have an Ignite cluster setup with two server nodes running. You can start as many nodes as you like. Ignite will automatically discover all the nodes.
4. Add Ignite Depedency
Add the following Ignite dependencies in your project’s pom.xml file:
<dependency>
<groupId>org.apache.ignite</groupId>
<artifactId>ignite-core</artifactId>
<version>1.5.0-b1</version>
</dependency>
<dependency>
<groupId>org.apache.ignite</groupId>
<artifactId>ignite-spring</artifactId>
<version>1.5.0-b1</version>
</dependency>
5. HelloWorld.java
Here is a sample HelloWord.java file that prints ‘Hello World’ on all the nodes in the cluster.
import org.apache.ignite.Ignite;
import org.apache.ignite.IgniteCache;
import org.apache.ignite.IgniteException;
import org.apache.ignite.Ignition;
public class HelloWorld {
public static void main(String[] args) throws IgniteException {
try (Ignite ignite = Ignition.start("examples/config/example-ignite.xml")) {
// Put values in cache.
IgniteCache<Integer, String> cache = ignite.getOrCreateCache("myCache");
cache.put(1, "Hello");
cache.put(2, "World!");
// Get values from cache and
// broadcast 'Hello World' on all the nodes in the cluster.
ignite.compute().broadcast(() -> {
String hello = cache.get(1);
String world = cache.get(2);
System.out.println(hello + " " + world);
});
}
}
}
6. Project Structure
Review project directory structure.
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7. Set VM Options in IDEA
Go to Run --> Edit Configurations --> VM options (under Configuration tab) and enter:
-DIGNITE_HOME=<path-to-Ignite-installation-folder>
This step is required only because we are trying to provide a relative path to the configuration file in our code (line #7). You can skip this step and provide an absolute path instead.
8. Output
Run HelloWorld.java. You will see ‘Hello World!’ printed on all three nodes.
On IDEA console
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On both terminals
For more information, documentation, and screencasts, visit the Apache Ignite website.
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Screencast
If you prefer to watch a running example, here is a short screencast.For more information, documentation, and screencasts, visit the Apache Ignite website.
