Random Services Notes

References

• Spring Boot Profiles - Application Configuration made easy
• Quick Intro to Spring Cloud Configuration
• Testing in Production — Building Observable Distributed System
• HTTP Status Codes: full list of http status code and what it means for each of them.

Rule Engine

• Drools Rule Engine Tutorial

Run Services

mvn clean install to build and mvn package -P devint-test cargo:run to run from within the “web” module; to debug mvnDebug package -P devint-test cargo:run, and then set up Remote Java Application to connect to the listening port - 8000. See this stackoverflow for arguments - MAVEN_DEBUG_OPT=-Xdebug -Xrunjdwp:transport=dt_socket,server=y,suspend=y,address=8000

Use -DskipTests to skip tests.

Attach source code and docs

Simple, get your sources and JavaDocs:

mvn dependency:resolve -Dclassifier=javadoc -Dclassifier=sources

To download sources for your dependencies: mvn eclipse:eclipse -DdownloadSources=true

To attach sources to an installation: mvn source:jar install

From this stackoverflow

Session Validation

@Component
public class SessionValidationInterceptorAdapter extends HandlerInterceptorAdapter {

  private static final Logger logger = LoggerFactory.getLogger(SessionValidationInterceptorAdapter.class);


  public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler)
      throws Exception {
    
    HandlerMethod method = (HandlerMethod) handler;
    SessionValidationToken methodAnnotation =
        method.getMethodAnnotation(SessionValidationToken.class);

    GroupSessionValidationToken classAnnotation =
        method.getMethod().getDeclaringClass().getAnnotation(GroupSessionValidationToken.class);

		if (methodAnnotation != null || classAnnotation != null) {

			// Decipher and validate the session token.
			try {
				UserToken userToken = new UserToken();
				token = request.getHeader("Authorization").trim();

				//decrypt the token and check its validity
				if (this.isValid(userToken)) {
					return true;
				}
			} finally {
				response.setStatus(HttpServletResponse.SC_UNAUTHORIZED);
				return false;
			}
  }

  @Override
  public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler,
      ModelAndView modelAndView) throws Exception {

  }

}

Spring AOP and @AspectJ

• Spring AOP + @AspectJ Annotation Example with @Aspect, @Pointcut, @Before, @After, @Around, @AfterReturning, @AfterThrowing Advice
• Aspect Oriented Programming with Spring

1. Define Aspect Config

@Configuration
@EnableAspectJAutoProxy
@ComponentScan(basePackages="com.concretepage")
public class AspectConfig {
}  

2. Define annotation

@Retention(RetentionPolicy.RUNTIME)
@Target(ElementType.METHOD)
public @interface Auditable {
    AuditCode value();
}

3. Define advice with point cut expression

@Before("com.xyz.lib.Pointcuts.anyPublicMethod() && @annotation(auditable)")
public void audit(Auditable auditable) {
    AuditCode code = auditable.value();
    // ...
}

4. Note that point cut can be defined separately from Advice -

@Pointcut("com.xyz.lib.Pointcuts.anyPublicMethod() && @annotation(auditable)")
public void pointcutDemo() {}

@Before("pointcutDemo())")
public void audit(Auditable auditable) {
    AuditCode code = auditable.value();
    // ...
}