Adds loan application workflow spec.

applications/loan-application/.gitattributes

@@ -0,0 +1,9 @@
+#
+# https://help.github.com/articles/dealing-with-line-endings/
+#
+# Linux start script should use lf
+/gradlew        text eol=lf
+
+# These are Windows script files and should use crlf
+*.bat           text eol=crlf
+

applications/loan-application/.gitignore

@@ -0,0 +1,5 @@
+# Ignore Gradle project-specific cache directory
+.gradle
+
+# Ignore Gradle build output directory
+build

applications/loan-application/app/build.gradle

@@ -0,0 +1,30 @@
+/*
+ * This file was generated by the Gradle 'init' task.
+ *
+ * This generated file contains a sample Java application project to get you started.
+ * For more details take a look at the 'Building Java & JVM projects' chapter in the Gradle
+ * User Manual available at https://docs.gradle.org/8.0.2/userguide/building_java_projects.html
+ */
+
+plugins {
+    // Apply the application plugin to add support for building a CLI application in Java.
+    id 'application'
+}
+
+repositories {
+    // Use Maven Central for resolving dependencies.
+    mavenCentral()
+}
+
+dependencies {
+
+    implementation 'io.littlehorse:littlehorse-client:0.7.2'
+
+    // This dependency is used by the application.
+    implementation 'com.google.guava:guava:31.1-jre'
+}
+
+application {
+    // Define the main class for the application.
+    mainClass = 'io.littlehorse.demo.loanapproval.App'
+}

applications/loan-application/app/src/main/java/io/littlehorse/demo/loanapproval/App.java

@@ -0,0 +1,10 @@
+package io.littlehorse.demo.loanapproval;
+
+import io.littlehorse.sdk.common.config.LHConfig;
+
+public class App {
+
+    public static void main(String[] args) {
+        LHConfig config = new LHConfig();
+    }
+}

applications/loan-application/app/src/main/java/io/littlehorse/demo/loanapproval/workflows/LoanApprovalWorkflow.java

@@ -0,0 +1,133 @@
+package io.littlehorse.demo.loanapproval.workflows;
+
+import io.littlehorse.sdk.common.proto.Comparator;
+import io.littlehorse.sdk.common.proto.LHErrorType;
+import io.littlehorse.sdk.common.proto.PutExternalEventDefRequest;
+import io.littlehorse.sdk.common.proto.VariableMutationType;
+import io.littlehorse.sdk.common.proto.VariableType;
+import io.littlehorse.sdk.common.proto.LittleHorseGrpc.LittleHorseBlockingStub;
+import io.littlehorse.sdk.usertask.UserTaskSchema;
+import io.littlehorse.sdk.wfsdk.LHFormatString;
+import io.littlehorse.sdk.wfsdk.NodeOutput;
+import io.littlehorse.sdk.wfsdk.UserTaskOutput;
+import io.littlehorse.sdk.wfsdk.WfRunVariable;
+import io.littlehorse.sdk.wfsdk.Workflow;
+import io.littlehorse.sdk.wfsdk.WorkflowThread;
+
+public class LoanApprovalWorkflow {
+
+    public static final String LOAN_APPROVAL_WF = "loan-approval";
+
+    public static final String CUSTOMER_ID_VAR = "customer-id";
+    public static final String LOAN_AMOUNT_VAR = "loan-amount";
+    public static final String STATUS_VAR = "status";
+    public static final String INTERNAL_RISK_SCORE_VAR = "internal-risk-score";
+    public static final String CREDIT_SCORE_VAR = "credit-score";
+    public static final String REQUIRED_DOCUMENTS_VAR = "required-documents";
+    public static final String PROVIDED_DOCUMENTS_VAR = "provided-documents";
+
+    public static final String FETCH_CREDIT_SCORE_TASK = "fetch-credit-score";
+    public static final String CALCULATE_RISK_SCORE_TASK = "calculate-risk-score";
+    public static final String DETERMINE_NEEDED_DOCS_TASK = "determine-required-documents";
+    public static final String REQUEST_DOCUMENTATION_TASK = "request-documentation";
+    public static final String STORE_COMMENTS_TASK = "store-comments-on-application";
+    public static final String APPROVE_APPLICATION_TASK = "approve-loan-application";
+    public static final String REJECT_APPLICATION_TASK = "reject-loan-application";
+
+    public static final String DOCUMENTS_PROVIDED_EVENT = "documents-provided";
+
+    public static final String MANUAL_APPROVAL_USER_TASK = "manual-loan-approval";
+
+    private WfRunVariable customerId;
+    private WfRunVariable loanAmount;
+
+    private WfRunVariable status;
+    private WfRunVariable internalRiskScore;
+    private WfRunVariable creditScore;
+    private WfRunVariable requiredDocuments;
+
+    private LittleHorseBlockingStub client;
+
+    public LoanApprovalWorkflow(LittleHorseBlockingStub client) {
+        this.client = client;
+    }
+
+    public void registerWorkflow() {
+        UserTaskSchema userTaskSchema = new UserTaskSchema(new ManualLoanApprovalResult(), MANUAL_APPROVAL_USER_TASK);
+        client.putUserTaskDef(userTaskSchema.compile());
+
+        client.putExternalEventDef(PutExternalEventDefRequest.newBuilder().setName(DOCUMENTS_PROVIDED_EVENT).build());
+
+        client.putWfSpec(Workflow.newWorkflow(LOAN_APPROVAL_WF, this::doWf).compileWorkflow());
+    }
+
+    private void doWf(WorkflowThread wf) {
+        customerId = wf.addVariable(CUSTOMER_ID_VAR, VariableType.STR).required().searchable();
+        loanAmount = wf.addVariable(LOAN_AMOUNT_VAR, VariableType.INT).required();
+        status = wf.addVariable(STATUS_VAR, "PENDING_APPROVAL").searchable();
+
+        internalRiskScore = wf.addVariable(INTERNAL_RISK_SCORE_VAR, VariableType.INT);
+        creditScore = wf.addVariable(CREDIT_SCORE_VAR, VariableType.INT);
+        requiredDocuments = wf.addVariable(REQUIRED_DOCUMENTS_VAR, VariableType.JSON_ARR);
+
+        // Fetch the credit score
+        wf.mutate(creditScore, VariableMutationType.ASSIGN, wf.execute(FETCH_CREDIT_SCORE_TASK, customerId));
+
+        // Calculate Risk Score
+        NodeOutput riskScoreOutput = wf.execute(CALCULATE_RISK_SCORE_TASK, loanAmount, creditScore);
+        wf.mutate(internalRiskScore, VariableMutationType.ASSIGN, riskScoreOutput);
+
+        // If it's a "risky" loan, then we must manually approve it.
+        wf.doIf(wf.condition(internalRiskScore, Comparator.GREATER_THAN, 50), this::manuallyApprove);
+
+        // Determine needed documents for this loan
+        NodeOutput requiredDocsOutput = wf.execute(DETERMINE_NEEDED_DOCS_TASK, loanAmount, creditScore, customerId);
+        wf.mutate(requiredDocuments, VariableMutationType.ASSIGN, requiredDocsOutput);
+
+        // Mark workflow as "pending documentation"
+        wf.mutate(status, VariableMutationType.ASSIGN, "PENDING_DOCUMENTATION");
+
+        // Request required documents from customer
+        wf.execute(REQUEST_DOCUMENTATION_TASK, customerId, requiredDocuments);
+
+        // Wait for customer to provide docs. Maximum 5 days.
+        NodeOutput docsResult = wf.waitForEvent(DOCUMENTS_PROVIDED_EVENT).timeout(60 * 60 * 24 * 5);
+        wf.handleError(docsResult, LHErrorType.TIMEOUT, handler -> {
+            handler.mutate(status, VariableMutationType.ASSIGN, "CANCELLED");
+
+            handler.execute(REJECT_APPLICATION_TASK, "Customer did not provide required documentation.");
+            handler.fail("documentation-timeout", "Customer did not provide required documentation.");
+        });
+
+        wf.mutate(status, VariableMutationType.ASSIGN, "APPROVED");
+        wf.execute(APPROVE_APPLICATION_TASK, customerId, loanAmount);
+    }
+
+    private void manuallyApprove(WorkflowThread wf) {
+        // Assign a UserTask to the approval group to approve/reject the transfer.
+        LHFormatString notes = wf.format("User {0} requests a loan of ${1}, credit score {2}, risk score {3}.",
+                customerId, loanAmount, creditScore, internalRiskScore);
+
+        WfRunVariable manuallyApproved = wf.addVariable("manually-approved", VariableType.BOOL);
+        WfRunVariable comments = wf.addVariable("manual-comments", VariableType.STR);
+
+        UserTaskOutput taskResult = wf.assignUserTask(MANUAL_APPROVAL_USER_TASK, null, "approvals-team").withNotes(notes);
+
+        wf.mutate(manuallyApproved, VariableMutationType.ASSIGN, taskResult.jsonPath("$.isApproved"));
+        wf.mutate(comments, VariableMutationType.ASSIGN, taskResult.jsonPath("$.comments"));
+
+        wf.execute("store-comments-on-application", comments);
+
+        // Fail the workflow if the user dis-approved the task.
+        wf.doIf(wf.condition(manuallyApproved, Comparator.EQUALS, false), ifBody -> {
+            wf.mutate(status, VariableMutationType.ASSIGN, "REJECTED");
+            wf.execute(REJECT_APPLICATION_TASK, comments);
+            wf.fail("application-rejected", "Application was rejected");
+        });
+    }
+}
+
+class ManualLoanApprovalResult {
+    public boolean isApproved;
+    public String comments;
+}

applications/loan-application/gradle/wrapper/gradle-wrapper.properties

@@ -0,0 +1,6 @@
+distributionBase=GRADLE_USER_HOME
+distributionPath=wrapper/dists
+distributionUrl=https\://services.gradle.org/distributions/gradle-8.0.2-bin.zip
+networkTimeout=10000
+zipStoreBase=GRADLE_USER_HOME
+zipStorePath=wrapper/dists