I am using Flowable 6.4.1 in spring-boot to create processes and run from my java code, but requirement is to not use any xml, so due to this I have hit a blockade.
I have a user task, taking input from user, depending on that input, call to corresponding service task is made.
Below is a short example of what I am going to do:
basic-process.bpmn20.xml:
<process id="basicprocess" name="Basic Process" isExecutable="true">
<startEvent id="startEvent"/>
<sequenceFlow sourceRef="startEvent" targetRef="getInput"/>
<userTask id="getInput" name="Get input from user" />
<sequenceFlow sourceRef="getInput" targetRef="decision"/>
<exclusiveGateway id="decision"/>
<sequenceFlow sourceRef="decision" targetRef="firstServiceTask">
<conditionExpression xsi:type="tFormalExpression">
<![CDATA[
${number>100}
]]>
</conditionExpression>
</sequenceFlow>
<sequenceFlow sourceRef="decision" targetRef="secondServiceTask">
<conditionExpression xsi:type="tFormalExpression">
<![CDATA[
${number<=100}
]]>
</conditionExpression>
</sequenceFlow>
<serviceTask id="firstServiceTask" name="Number is greater than predefined target"
flowable:class="demo.service.tasks.FirstServiceTask"/>
<sequenceFlow sourceRef="firstServiceTask" targetRef="greaterEnd"/>
<serviceTask id="secondServiceTask" name="Number is less than predefined target"
flowable:class="demo.service.tasks.SecondServiceTask"/>
<sequenceFlow sourceRef="secondServiceTask" targetRef="lesserEnd"/>
<endEvent id="greaterEnd"/>
<endEvent id="lesserEnd"/>
</process>
Above, XML shows the process and I'm starting the process using REST API
Below is the controller:
DefinitionsController.java:
#RestController
#SuppressWarnings("rawtypes")
public class DefinitionsController {
#Autowired
private RepositoryService mRepositoryService;
#Autowired
private RuntimeService mRuntimeService;
#Autowired
private TaskService mTaskService;
#PostMapping("/start-service")
public String startService(#RequestBody String input) {
Integer request = Integer.parseInt(input);
Map<String, Object> variables = new HashMap<String, Object>();
variables.put("number", request);
ProcessInstance instance = mRuntimeService.startProcessInstanceByKey("basicprocess", variables);
Task userTask = mTaskService.createTaskQuery().processInstanceId(instance.getId()).taskDefinitionKey("getInput").singleResult();
mTaskService.complete(userTask.getId());
return "ProcessInstance id is "+instance.getProcessInstanceId();
}
}
FirstServiceTask.java:
public class FirstServiceTask implements JavaDelegate{
#Override
public void execute(DelegateExecution execution) {
System.err.println("Came in first service task");
}
}
Same for SecondServiceTask.java except the sysout statement.
REST RESPONSE: I get the processInstance Id and sysout statement of respective service task gets printed in console..
Pretty easy to wire the Service Task classes from xml, however if I were to not use XML, I would need to create the same process using flowable-modeler api of FLOWABLE.
So, basically I want to have control over those service tasks from my java code and in order to do that how do I wire the Service Tasks that are created using flowable-modeler with my java code ?
I have gone through docs, but found the xml way only.
Configuring Service Tasks (created using flowable-modeler) with Java code can be done by the 4 ways shown here.
The delegate expression which is going to be configured should be either present on the classpath or should have a spring-bean created.
I created bean using a method in main class, and put the name of method in delegate expressionattribute in flowable-modeler/process api and that's what was needed to do that.
Attached image should clarify things, which shows the way to wire Service Tasks (created using flowable-modeler API) with Java classes in workspace.
firstServiceTask in highlighted field is the method which returns bean of FirstServiceTask
EDIT: Apart from above solution, we can also specify class name in class field alone and all configuration is done. Forex: I have a class called TestClass.java in package org.flowable.learning, so I'll just specify org.flowable.learning.TestClass in class field, which is just above highlighted Delegate expression field in attached screenshot
Related
I am facing one issue.
I am calling some API's in parallel using Spring Webflux. If any child thread faces any issue, it needs to log the request. Now the issue is , for logging a normal POJO class in which there is a static method which gets a bean via ApplicationContent and store the data in a Queue.
Now the issue is, I want to access request params like Request URL / Controller etc.
I tried
ServletRequestAttributes sra =
(ServletRequestAttributes)RequestContextHolder.getRequestAttributes();
logger.error("====="+sra);
HttpServletRequest httpRequest = sra.getRequest();
but In this case, sra is null. I tried adding the following code,
#Configuration
public class InheritableRequestContextListener extends RequestContextListener {
private static final String REQUEST_ATTRIBUTES_ATTRIBUTE =
InheritableRequestContextListener.class.getName() + ".REQUEST_ATTRIBUTES";
#Override
public void requestInitialized(ServletRequestEvent requestEvent) {
System.out.println("111111111111111111");
if (!(requestEvent.getServletRequest() instanceof HttpServletRequest)) {
throw new IllegalArgumentException(
"Request is not an HttpServletRequest: " + requestEvent.getServletRequest());
}
HttpServletRequest request = (HttpServletRequest) requestEvent.getServletRequest();
ServletRequestAttributes attributes = new ServletRequestAttributes(request);
request.setAttribute(REQUEST_ATTRIBUTES_ATTRIBUTE, attributes);
LocaleContextHolder.setLocale(request.getLocale());
RequestContextHolder.setRequestAttributes(attributes, true);
}
}
but this is not helping. Can anyone help. I am using springboot version ; 2.0.2.RELEASE.
There are several reasons as to why your implementation does not work.
Webflux is thread agnostic, which means that any thread can deal with anything at anytime in the application. If the application finds it efficiant to switch the current executing thread, it will do so.
Servlet applications on the other hand assigns one thread to each request and sticks with that thread throughtout execution.
ApplicationContext uses as you can see ServletRequests, so it is not usable in a Webflux application. It in turn uses threadlocal to store the request object to the designated thread.
In webflux you cant use threadlocal, bucase as soon as the application switches threads everything in threadlocal is gone. Thats why you get null.
So how do you pass data from thread to thread.
What you need to do is to implement a filter that intercepts the request, extracs the information you want and places it in the reactive context object.
https://projectreactor.io/docs/core/release/reference/#context
Here is a post that addresses the problem.
https://developpaper.com/implementation-of-requestcontextholder-in-spring-boot-webflux/
In my application, I need to call an external endpoint and if it is too slow a fallback is activated.
The following code is an example of how my app looks like:
#FeignClient(name = "${config.name}", url = "${config.url:}", fallback = ExampleFallback.class)
public interface Example {
#RequestMapping(method = RequestMethod.GET, value = "/endpoint", produces = MediaType.APPLICATION_JSON_VALUE, consumes = MediaType.APPLICATION_JSON_VALUE)
MyReturnObject find(#RequestParam("myParam") String myParam);
}
And its fallback implementation:
#Component
public Class ExampleFallback implements Example {
private final FallbackService fallback;
#Autowired
public ExampleFallback(final FallbackService fallback) {
this.fallback = fallback;
}
#Override
public MyReturnObject find(final String myParam) {
return fallback.find(myParam);
}
Also, a configured timeout for circuit breaker:
hystrix.command.default.execution.isolation.thread.timeoutInMilliseconds: 5000
How can I implement an integration test to check if my circuit break is working, i.e, if my endpoint (mocked in that case) is slow or if it returns an error like 4xx or 5xx?
I'm using Spring Boot 1.5.3 with Spring Cloud (Feign + Hystrix)
Note i donot know Feign or Hystrix.
In my opinion it is problematic to implement an automated integrationtest that simulates different implementatondetails of Feign+Hystrix - this implementation detail can change at any time. There are many different types of failure: primary-Endpoint not reachable, illegal data (i.e. receiving a html-errormessage, when exprecting xml data in a special format), disk-full, .....
if you mock an endpoint you make an assumption of implementationdetail of Feign+Hystrix how the endpoint behaves in a errorsituation (i.e. return null, return some specific errorcode, throw an exception of type Xyz....)
i would create only one automated integration test with a real primary-enpoint that has a never reachable url and a mocked-fallback-endpoint where you verify that the processed data comes from the mock.
This automated test assumes that handling of "networkconnection too slow" is the same as "url-notfound" from your app-s point of view.
For all other tests i would create a thin wrapper interface around Feign+Hystrix where you mock Feign+Hystrix. This way you can automatically test for example what happens if you receive 200bytes from primary interface and then get an expetion.
For details about hiding external dependencies see onion-architecture
I got a CXF OSGi Web service (based on the example demo in servicemix: https://github.com/apache/servicemix/tree/master/examples/cxf/cxf-jaxws-blueprint)
The Web service works fine and i call all the available implemented methods of the service.
My question is how can i retrieve the request inside a WS method and parse in a string XML format.
I have found that this is possible inside interceptors for logging, but i want also to the WS-Request inside my methods.
For storing the request in the database I suggest to extend the new CXF message logging.
You can implement a custom LogEventSender that writes into the database.
I had similar requirement where I need to save data into DB once method is invoked. I had used ThreadLocal with LoggingInInterceptor and LoggingOutInterceptor. For example in LoggingInInterceptor I used to set the message into ThreadContext and in webservice method get the message using LoggingContext.getMessage() and in LoggingOutInterceptor I used to removed the message(NOTE: Need to be careful here you need to explictly remove the message from thread context else you will end up with memory leak, and also incase of client side code interceptors get reversed.
public class LoggingContext {
private static ThreadLocal<String> message;
public static Optional<String> getMessage() {
return Optional.ofNullable(message.get());
}
public static void setMessage(final String message) {
LoggingContext.message = new ThreadLocal<>();
LoggingContext.message.set(message);
}
}
Not an answer to this question but i achieved to do my task by using JAXB in the end and do some manipulations there.
I'm working on a Web API RESTful service that on a request needs to perform a task. We're using Hangfire to execute that task as a job, and on failure, will attempt to retry the job up to 10 times.
If the job eventually succeeds I want to run an additional job (to send an event to another service). If the job fails even after all of the retry attempts, I want to run a different additional job (to send a failure event to another service).
However, I can't figure out how to do this. I've created the following JobFilterAttribute:
public class HandleEventsAttribute : JobFilterAttribute, IElectStateFilter
{
public IBackgroundJobClient BackgroundJobClient { get; set; }
public void OnStateElection(ElectStateContext context)
{
var failedState = context.CandidateState as FailedState;
if (failedState != null)
{
BackgroundJobClient.Enqueue<MyJobClass>(x => x.RunJob());
}
}
}
The one problem I'm having is injecting the IBackgroundJobClient into this attribute. I can't pass it as a property to the attribute (I get a "Cannot access non-static field 'backgroundJobClient' in static context" error). We're using autofac for dependency injection, and I tried figuring out how to use property injection, but I'm at a loss. All of this leads me to believe I may be on the wrong track.
I'd think it would be a fairly common pattern to run some additional cleanup code if a Hangfire job fails. How do most people do this?
Thanks for the help. Let me know if there's any additional details I can provide.
Hangfire can build an execution chains. If you want to schedule next job after first one succeed, you need to use ContinueWith(string parentId, Expression<Action> methodCall, JobContinuationOptions options); with the JobContinuationOptions.OnlyOnSucceededState to run it only after success.
But you can create a HangFire extension like JobExecutor and run tasks inside it to get more possibilities.
Something like that:
public static JobResult<T> Enqueue<T>(Expression<Action> a, string name)
{
var exprInfo = GetExpressionInfo(a);
Guid jGuid = Guid.NewGuid();
var jobId = BackgroundJob.Enqueue(() => JobExecutor.Execute(jGuid, exprInfo.Method.DeclaringType.AssemblyQualifiedName, exprInfo.Method.Name, exprInfo.Parameters, exprInfo.ParameterTypes));
JobResult<T> result = new JobResult<T>(jobId, name, jGuid, 0, default(T));
JobRepository.WriteJobState(new JobResult<T>(jobId, name, jGuid, 0, default(T)));
return result;
}
More detailed information you can find here: https://indexoutofrange.com/Don%27t-do-it-now!-Part-5.-Hangfire-job-continuation,-ContinueWith/
I haven't been able to verify this will work, but BackgroundJobClient has no static methods, so you would need a reference to an instance of it.
When I enqueue tasks, I use the static Hangfire.BackgroundJob.Enqueue which should work without a reference to the JobClient instance.
Steve
My silverlight solution has 3 project files
Silverlight part(Client)
Web part(Server)
Entity model(I maintained the edmx along with Metadata in a seperate project)
Metadata file is a partial class with relavent dataannotation validations.
[MetadataTypeAttribute(typeof(User.UserMetadata))]
public partial class User
{
[CustomValidation(typeof(UsernameValidator), "IsUsernameAvailable")]
public string UserName { get; set; }
}
Now my question is where I need to keep this class UsernameValidator
If my Metadata class and edmx are on Server side(Web) then I know I need to create a .shared.cs class in my web project, then add the proper static method.
My IsUserAvailable method intern will call a domainservice method as part of asyc validation.
[Invoke]
public bool IsUsernameAvailable(string username)
{
return !Membership.FindUsersByName(username).Cast<MembershipUser>().Any();
}
If my metadata class is in the same project as my domain service is in then I can call domain service method from my UsernameValidator.Shared.cs class.
But here my entity models and Metadata are in seperate library.
Any idea will be appreciated
Jeff wonderfully explained the asyc validation here
http://jeffhandley.com/archive/2010/05/26/asyncvalidation-again.aspx
but that will work only when your model, metadata and Shared class, all are on server side.
There is a kind of hack to do this. It is not a clean way to do it it, but this is how it would probably work.
Because the .shared takes care of the code generation it doesn't complain about certain compile errors in the #if brackets of the code. So what you can do is create a Validator.Shared.cs in any project and just make sure it generates to the silverlight side.
Add the following code. and dont forget the namespaces.
#if SILVERLIGHT
using WebProject.Web.Services;
using System.ServiceModel.DomainServices.Client;
#endif
#if SILVERLIGHT
UserContext context = new UserContext();
InvokeOperation<bool> availability = context.DoesUserExist(username);
//code ommited. use what logic you want, maybe Jeffs post.
#endif
The compiler will ignore this code part because it does not meet the condition of the if statement. Meanwhile on the silverlight client side it tries to recompile the shared validator where it DOES meet the condition of the if-statement.
Like I said. This is NOT a clean way to do this. And you might have trouble with missing namespaces. You need to resolve them in the non-generated Validator.shared.cs to finally let it work in silverlight. If you do this right you can have the validation in silverlight with invoke operations. But not in your project with models and metadata like you would have with Jeff's post.
Edit: I found a cleaner and better way
you can create a partial class on the silverlight client side and doing the following
public partial class User
{
partial void OnUserNameChanging(string value)
{
//must be new to check for this validation rule
if(EntityState == EntityState.New)
{
var ctx = new UserContext();
ctx.IsValidUserName(value).Completed += (s, args) =>
{
InvokeOperation invop = (InvokeOperation) s;
bool isValid = (bool) invop.Value;
if(!isValid)
{
ValidationResult error = new ValidationResult(
"Username already exists",
new string[] {"UserName"});
ValidationErrors.Add(error;
}
};
}
}
}
This is a method generated by WCF RIA Services and can be easily partialled and you can add out-of-band validation like this. This is a much cleaner way to do this, but still this validation now only exists in the silverlight client side.
Hope this helps