Big data space: java

This post is how to connect a websocket which is secured by Basic Authentication.

I will be using javax.websocket-api jar file.

Create WebContainer object

WebSocketContainer container = ContainerProvider.getWebSocketContainer();

using the container connect to the service

1	container.connectToServer(endpoint, clientConfig, new URI("wss://hostname:port/demo"));

credentials are passed to clientConfig object.

ClientEndpointConfig.Configurator configurator = new ClientEndpointConfig.Configurator() {
             public void beforeRequest(Map<String, List<String>> headers) {
          String credentials = "username:password";
          headers.put("Authorization", Arrays.asList("Basic " + new BASE64Encoder().encode(credentials.getBytes())));
                 System.out.println("Header set successfully");
             }
         };

         ClientEndpointConfig clientConfig = ClientEndpointConfig.Builder.create()
                 .configurator(configurator)
                 .build();

endpoint is the callback handler. Once the session is established with the service then we pass a message using the session object. onMessage() method should be overridden to receive the message.

Endpoint endpoint = new Endpoint() {
  @Override
                public void onOpen(Session session, EndpointConfig config) {
                    session.addMessageHandler(new MessageHandler.Whole<String>() {
                        @Override
                        public void onMessage(String content) {
                            System.out.println("Received message: "+content);
                        }
                    });
                    try {
                 System.out.println("Sending message to endpoint: " + msg);
                        System.out.println("Session Id:: "+session.getId());
   session.getBasicRemote().sendText(msg);
      } catch (Exception e) {
   e.printStackTrace();
      }
                }
            };

Create an Eclipse java maven project.

Add Scala nature to the project Right click on project > Configure > Add Scala Nature

Create project structure as:
src/main/java
src/main/scala

Sample Java class:

package test.java;

public class Hello {

    public static void main(String[] args) {
        Hello hello = new Hello();
        hello.helloUser("Tomcat");

    }

    public void helloUser(String user) {
        System.out.println("Hello " + user);
    }

}

Calling java class from Scala class

package test.scala;

import test.java.Hello

object HelloScala {

  def helloScala() {
    val hello = new Hello()
    hello.helloUser("Scala")
  }
}

POM file:

<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>Java_Scala_Project</groupId>
    <artifactId>Java_Scala_Project</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <dependencies>
        <dependency>
            <groupId>org.scala-lang</groupId>
            <artifactId>scala-library</artifactId>
            <version>2.10.4</version>
        </dependency>

    </dependencies>

    <!-- <repositories>
        <repository>
            <id>scala</id>
            <name>Scala Tools</name>
            <url>http://scala-tools.org/repo-releases/</url>
            <releases>
                <enabled>true</enabled>
            </releases>
            <snapshots>
                <enabled>false</enabled>
            </snapshots>
        </repository>
    </repositories> -->

    <pluginRepositories>
        <pluginRepository>
            <id>scala</id>
            <name>Scala Tools</name>
            <url>http://scala-tools.org/repo-releases/</url>
            <releases>
                <enabled>true</enabled>
            </releases>
            <snapshots>
                <enabled>false</enabled>
            </snapshots>
        </pluginRepository>
    </pluginRepositories>

    <build>
        <sourceDirectory>src</sourceDirectory>
        <plugins>
            <plugin>
                <artifactId>maven-compiler-plugin</artifactId>
                <version>3.3</version>
                <configuration>
                    <source>1.7</source>
                    <target>1.7</target>
                </configuration>
            </plugin>
            <plugin>
                <groupId>org.scala-tools</groupId>
                <artifactId>maven-scala-plugin</artifactId>
                <executions>
                    <execution>
                        <goals>
                            <goal>compile</goal>
                            <goal>testCompile</goal>
                        </goals>
                    </execution>
                </executions>
            </plugin>
            <plugin>
                <groupId>org.scala-tools</groupId>
                <artifactId>maven-scala-plugin</artifactId>
                <executions>
                    <execution>
                        <id>compile</id>
                        <goals>
                            <goal>compile</goal>
                        </goals>
                        <phase>compile</phase>
                    </execution>
                    <execution>
                        <id>test-compile</id>
                        <goals>
                            <goal>testCompile</goal>
                        </goals>
                        <phase>test-compile</phase>
                    </execution>
                    <execution>
                        <phase>process-resources</phase>
                        <goals>
                            <goal>compile</goal>
                        </goals>
                    </execution>
                </executions>
            </plugin>
        </plugins>
    </build>
</project>

Big data space

Wednesday, October 25, 2017

Java Client for Secure Web Socket

Monday, November 14, 2016

How to call a java class from scala

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