fjtirado commented on code in PR #585:
URL:
https://github.com/apache/incubator-kie-kogito-docs/pull/585#discussion_r1526343238
##########
serverlessworkflow/modules/ROOT/pages/getting-started/java-embedded-workflows.adoc:
##########
@@ -0,0 +1,104 @@
+= Workflow embedded execution in Java
+
+This guide show cases how to execute a link:{spec_doc_url}[CNCF Serverless
Workflow] definition using a standard java virtual machine and a small set of
Maven dependencies. Therefore, it is assumed you are fluent both in Java and
Maven.
+The workflow definition to be executed can be read from a .json or .yaml file
or programatically defined using the {product_name} fluent API.
+
+[[embedded-file-quick-start]]
+== Hello world (using existing definition file)
+
+First step is to setup an empty Maven project with the following dependency.
+
+[source,xml]
+----
+<dependency>
+ <groupId>org.kie.kogito</groupId>
+ <artifactId>kogito-serverless-workflow-executor-core</artifactId>
+ <version>RELEASE</version>
+</dependency>
+----
+
+Also, you might optionally add `simple logger for java` dependency to avoid
using `system.out.println`
+
+[source,xml]
+----
+ <dependency>
+ <groupId>org.slf4j</groupId>
+ <artifactId>slf4j-simple</artifactId>
+ <version>1.7.36</version>
+ </dependency>
+----
+
+Lets assume you already have a workflow definition written in a JSON file in
your project root. For example,
link:{kogito_sw_examples_url}/serverless-workflow-hello-world/src/main/resources/hello.sw.json[Hello
World] definition. In order to execute it, you need to write the following
main java class (standard imports and java package declaration are
intentionally skipped for brevity)
+
+[source,java]
+----
+import org.kie.kogito.serverless.workflow.executor.StaticWorkflowApplication;
+import org.kie.kogito.serverless.workflow.models.JsonNodeModel;
+import org.kie.kogito.serverless.workflow.utils.ServerlessWorkflowUtils;
+import org.kie.kogito.serverless.workflow.utils.WorkflowFormat;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import io.serverlessworkflow.api.Workflow;
+
+public class DefinitionFileExecutor {
+ private static final Logger logger =
LoggerFactory.getLogger(DefinitionFileExecutor.class);
+
+ public static void main(String[] args) throws IOException {
+ try (Reader reader = new FileReader("hello.sw.json"); <1>
+ StaticWorkflowApplication application =
StaticWorkflowApplication.create()) { <2>
+ Workflow workflow = ServerlessWorkflowUtils.getWorkflow(reader,
WorkflowFormat.JSON); <3>
+ JsonNodeModel result = application.execute(workflow,
Collections.emptyMap()); <4>
+ logger.info("Workflow execution result is {}",
result.getWorkflowdata()); <5>
+ }
+ }
+}
+----
+<1> Reads the workflow file definition from the project root directory
+<2> Creates a static workflow application object. It is done within the try
block since the instance is `Closeable`. This is the reference that allow you
to execute workflow definitions.
+<3> Reads the Serverless Workflow Java SDK `Workflow` object from the file.
+<4> Execute the workflow, passing `Workflow` reference and no parameters (an
empty Map). The result of the workflow execution: process instance id and
workflow output model, can accessed using `result` variable.
+<5> Prints the workflow model in the configured standard output.
+
+If you compile and execute this java class, you will see the following log in
your configured standard output
+----
+Workflow execution result is {"greeting":"Hello World","mantra":"Serverless
Workflow is awesome!"}
+----
+
+[[embedded-fluent-quick-start]]
+== Hello world (using fluent API)
+
+Using the same Maven setup than in the previous section, you can
programatically generate that workflow definition rather than loading it from a
file definition by using
link:{kogito_runtimes_url}/kogito-serverless-workflow/kogito-serverless-workflow-fluent/src/main/java/org/kie/kogito/serverless/workflow/fluent[fluent
API]
+
+Therefore, you can modify the previous example in a way that generates exactly
the same output when it is executed, but rather creating a `FileReader` that
reads the `Workflow` object, we create the `Workflow` object using java
statements. The resulting modified main method is the following
+
+[source,java]
+----
+ try (StaticWorkflowApplication application =
StaticWorkflowApplication.create()) {
+ Workflow workflow = workflow("HelloWorld"). <1>
+ start( <2>
+ inject( <3>
+
jsonObject().put("greeting", "Hello World").put("mantra","Serverless Workflow
is awesome!"))) <4>
+ .end() <5>
+ .build(); <6>
+ logger.info("Workflow execution result is
{}",application.execute(workflow, Collections.emptyMap()).getWorkflowdata());
<7>
+ }
+----
+<1> Creates a workflow which name is `HelloWorld`
+<2> Indicate that you are going to specify the start state
+<3> A Inject state is the start state
+<4> Inject state accepts static json, therefore this line creates the JSON data
+<5> End the workflow definition
+<6> Build the workflow definition
+<7> Execute and print as in previous example
+
+
+== Additional resources
+
+You can find additional and commented examples of fluent API usage (including
jq expression evaluation and orchestation of rest services)
link:https://github.com/fjtirado/java-flow/tree/main/java-flow-example/src/main/java/org/kie/kogito/serverless/workflow/examples[here]
Review Comment:
Created https://github.com/apache/incubator-kie-kogito-examples/pull/1895
for adding the examples
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