Spring HTTP-Remoting Connector Builder

• This example is based on the subclassed objects example.
• The example is using a Spring-Boot server application.
• The Spring-Boot application is started in a Docker container.

Spring Server Configuration

• Docker Configuration.
• Create Docker Image.
• Java main server program contains the datasource configuration and starts Spring-Boot.

Docker Containerization Config

Docker Configuration : Dockerfile

FROM openjdk:8u212-jdk-alpine3.9
WORKDIR /app
COPY target/spring_http_remoting_server.war /app
EXPOSE 8080
CMD ["java", "-jar", "spring_http_remoting_server.war"]

Create Docker Image

XML-File : pom.xml (part)

...
<plugin>
  <groupId>org.codehaus.mojo</groupId>
  <artifactId>exec-maven-plugin</artifactId>
  <executions>
    <execution>
      <id>docker-build</id>
      <phase>install</phase>
      <goals>
        <goal>exec</goal>
      </goals>
      <configuration>
        <executable>docker</executable>
        <workingDirectory>${project.basedir}</workingDirectory>
        <arguments>
          <argument>build</argument>
          <argument>-t</argument>
          <argument>spring_http_remoting_server:${project.version}</argument>
          <argument>.</argument>
        </arguments>
      </configuration>
    </execution>
  </executions>
</plugin>
...

Server Main Program

• Configure the Oracle datasource.
• Start the Spring-Boot server application.

Java Class : MainServer.java

package plsql_workspace_examples;

import java.sql.SQLException;

import javax.sql.DataSource;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;

import oracle.ucp.jdbc.PoolDataSource;
import oracle.ucp.jdbc.PoolDataSourceFactory;

@Configuration
@EnableAutoConfiguration
@ComponentScan("impl")
public class MainServer {
  @Bean
  DataSource dataSource() throws SQLException
  {
    PoolDataSource poolDataSource = PoolDataSourceFactory.getPoolDataSource();
    poolDataSource.setConnectionFactoryClassName("oracle.jdbc.pool.OracleDataSource");
    poolDataSource.setURL(System.getenv("db.url"));
    poolDataSource.setUser(System.getenv("db.username"));
    poolDataSource.setPassword(System.getenv("db.password"));
    poolDataSource.setInitialPoolSize(1);
    poolDataSource.setMinPoolSize(2);
    poolDataSource.setMaxPoolSize(10);
    poolDataSource.setLoginTimeout(10);
    poolDataSource.setInactiveConnectionTimeout(30);
    poolDataSource.setTimeoutCheckInterval(15);
    poolDataSource.setValidateConnectionOnBorrow(true);
    poolDataSource.setConnectionWaitTimeout(60);
    return poolDataSource;
  }

  public static void main(String[] args)
  {
    SpringApplication.run(MainServer.class, args);
  }
}

Client Configuration

• Start the Docker Container including the Oracle datasource parameter.
• Java example calling the remote service.

Start Docker Image

• The Docker Image is started during the Maven client build process.
• The Oracle Database configuration parameter are set as environment variables.

XML-File : pom.xml (part)

...
<plugin>
  <groupId>org.codehaus.mojo</groupId>
  <artifactId>exec-maven-plugin</artifactId>
  <executions>
    <!-- start docker -->
    <execution>
      <id>docker-start</id>
      <phase>process-test-classes</phase>
      <goals>
        <goal>exec</goal>
      </goals>
      <configuration>
        <executable>docker</executable>
        <workingDirectory>${project.basedir}</workingDirectory>
        <arguments>
          <argument>run</argument>
          <argument>--name</argument>
          <argument>spring_http_remoting_server</argument>
          <argument>--rm</argument>
          <argument>-p</argument>
          <argument>12345:8080</argument>
          <argument>-d</argument>
          <argument>-e</argument>
          <!-- configure the database url here -->
          <argument>db.url=jdbc:oracle:thin:@192.168.0.109:1521/orcl</argument>
          <argument>-e</argument>
          <!-- configure the database username here -->
          <argument>db.username=dbw_examples</argument>
          <argument>-e</argument>
          <!-- configure the database password here -->
          <argument>db.password=dbw_examples</argument>
          <argument>spring_http_remoting_server:${project.version}</argument>
        </arguments>
      </configuration>
    </execution>
</plugin>
...

Calling the Remote Services

Java Class : SubclassedObjectsSpringApi.java

package plsql_workbench_examples.springapi;

import java.sql.Date;
import java.sql.Timestamp;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;
import org.springframework.stereotype.Component;

import service.SubclassedObjectsService;
import transferobject.BaseObject;
import transferobject.DerivedObject;

@Component
public class SubclassedObjectsSpringApi {
  @Autowired
  private SubclassedObjectsService subclassedObjectsService;

  public static void main(String[] args)
  {
    System.setProperty("baseURL", "http://localhost:8080");
      
    // Register Spring Beans, Spring Context and call demo method 
    try (AnnotationConfigApplicationContext ctx = new AnnotationConfigApplicationContext("factory")) {
      ctx.register(SubclassedObjectsSpringApi.class);

      SubclassedObjectsSpringApi demo = ctx.getBean(SubclassedObjectsSpringApi.class);
      demo.runDemo();
    }
    catch (Exception e) {
      e.printStackTrace();
    }
  }

  private void runDemo()
  {
    try {
      int diff = 10;

      // create a base object from the database function
      BaseObject baseObject = subclassedObjectsService.getBaseObject();

      System.out.format("java-inspect: %s [d:%s/ts:%s/instance:%s/version:%d.%d]%n",
                        baseObject.getClass(),
                        baseObject.d,
                        baseObject.ts,
                        baseObject.instance,
                        baseObject.dbVersion,
                        baseObject.dbRelease);

      System.out.println("pl/sql inspect : " + subclassedObjectsService.inspectObject(baseObject));

      // create an derived object from the database function
      baseObject = subclassedObjectsService.getDerivedObject(diff);
      DerivedObject derivedObject = (DerivedObject) baseObject;
      System.out.format("java-inspect : %s [d:%s/ts:%s/instance:%s/version:%d.%d/newS:%s/newTs:%s/newD:%s/newN:%d]%n",
                        baseObject.getClass(),
                        baseObject.d,
                        baseObject.ts,
                        baseObject.instance,
                        baseObject.dbVersion,
                        baseObject.dbRelease,
                        derivedObject.newS,
                        derivedObject.newTs,
                        derivedObject.newD,
                        derivedObject.newN);

      System.out.println("pl/sql inspect : " + subclassedObjectsService.inspectObject(baseObject));

      // inspect of object instantiated in java
      derivedObject = new DerivedObject();
      derivedObject.d = new Date(System.currentTimeMillis());
      derivedObject.instance = "any string";
      derivedObject.ts = new Timestamp(System.currentTimeMillis());
      derivedObject.dbVersion = 88;
      derivedObject.dbRelease = 99;
      derivedObject.newD = new Date(0);
      derivedObject.newN = 1234567890;
      derivedObject.newS = "another string";
      derivedObject.newTs = new Timestamp((long) (Math.random() * 1000L * 3600L * 24L * 365L * 50L));
      System.out.println("pl/sql inspect () : " + subclassedObjectsService.inspectObject(derivedObject));
    }
    catch (Exception e) {
      e.printStackTrace();
    }
  }
}

Configuring and Running the Example

• The PL/SQL package has been installed in your Oracle database.
• Docker is installed and running.
• Configure the database connection parameter in the client/pom.xml.
• Just run mvn clean package from the Spring-Example parent folder.