Merge pull request #160 from bpm-crafters/feat/151-variable_converter

Allow to specify a converter per variable as an annotation attribute

Author: zambrovski

spring-boot-starter/src/main/kotlin/dev/bpmcrafters/processengine/worker/ProcessEngineWorker.kt

@@ -1,6 +1,5 @@
 package dev.bpmcrafters.processengine.worker
 
-import org.springframework.beans.factory.xml.BeanDefinitionParserDelegate.DEFAULT_VALUE
 import org.springframework.core.annotation.AliasFor
 
 /**

spring-boot-starter/src/main/kotlin/dev/bpmcrafters/processengine/worker/RejectJobException.kt

@@ -1,4 +1,11 @@
 package dev.bpmcrafters.processengine.worker
 
-class RejectJobException {
-}
+/**
+ * Special exception indicating the task rejection.
+ */
+class RejectJobException(
+  /**
+   * Reason for rejection.
+   */
+  override val message: String
+) : Exception()

spring-boot-starter/src/main/kotlin/dev/bpmcrafters/processengine/worker/Variable.kt

@@ -1,6 +1,8 @@
 package dev.bpmcrafters.processengine.worker
 
+import dev.bpmcrafters.processengine.worker.registrar.VariableConverter
 import org.springframework.core.annotation.AliasFor
+import kotlin.reflect.KClass
 
 /**
  * Indicates a typed process variable to be injected into the worker method.
@@ -9,25 +11,37 @@ import org.springframework.core.annotation.AliasFor
 @Target(AnnotationTarget.VALUE_PARAMETER, AnnotationTarget.ANNOTATION_CLASS)
 @MustBeDocumented
 annotation class Variable(
+  /**
+   * Name of the variable.
+   */
+  @get:AliasFor(attribute = "value")
+  val name: String = DEFAULT_UNNAMED_NAME,
+  /**
+   * Name of the variable.
+   */
+  @get:AliasFor(attribute = "name")
+  val value: String = DEFAULT_UNNAMED_NAME,
+  /**
+   * Indicates that a variable is mandatory. Defaults to `true`.
+   */
+  val mandatory: Boolean = true,
+  /**
+   * Specifies a converter class for this variable.
+   */
+  val converter: KClass<out VariableConverter> = DefaultVariableConverter::class,
+) {
+  /**
+   * Null object for converter, serves as a marker to use a globally defined converter.
+   * @since 0.5.1
+   */
+  object DefaultVariableConverter : VariableConverter {
+    override fun <T : Any> mapToType(value: Any?, type: Class<T>): T = throw NotImplementedError()
+  }
+
+  companion object {
     /**
-     * Name of the variable.
-     */
-    @get:AliasFor(attribute = "value")
-    val name: String = DEFAULT_UNNAMED_NAME,
-    /**
-     * Name of the variable.
-     */
-    @get:AliasFor(attribute = "name")
-    val value: String = DEFAULT_UNNAMED_NAME,
-    /**
-     * Indicates that a variable is mandatory. Defaults to `true`.
+     * Null value for the variable name.
      */
-    val mandatory: Boolean = true
-) {
-    companion object {
-        /**
-         * Null value for the variable name.
-         */
-        const val DEFAULT_UNNAMED_NAME = "__unnamed"
-    }
+    const val DEFAULT_UNNAMED_NAME = "__unnamed"
+  }
 }

spring-boot-starter/src/main/kotlin/dev/bpmcrafters/processengine/worker/configuration/ProcessEngineWorkerAutoConfiguration.kt

@@ -1,19 +1,18 @@
 package dev.bpmcrafters.processengine.worker.configuration
 
 import com.fasterxml.jackson.databind.ObjectMapper
-import dev.bpmcrafters.processengine.worker.registrar.VariableConverter
+import dev.bpmcrafters.processengine.worker.registrar.JacksonVariableConverter
 import dev.bpmcrafters.processengine.worker.registrar.ParameterResolver
 import dev.bpmcrafters.processengine.worker.registrar.ResultResolver
-import org.springframework.beans.factory.annotation.Qualifier
+import dev.bpmcrafters.processengine.worker.registrar.VariableConverter
 import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean
 import org.springframework.boot.context.properties.EnableConfigurationProperties
 import org.springframework.context.annotation.Bean
 import org.springframework.context.annotation.Configuration
-import java.util.concurrent.ExecutorService
-import java.util.concurrent.Executors
 
 /**
  * Auto configuration.
+ * @since 0.5.0
  */
 @Configuration
 @EnableConfigurationProperties(ProcessEngineWorkerProperties::class)
@@ -24,7 +23,8 @@ class ProcessEngineWorkerAutoConfiguration {
    */
   @Bean
   @ConditionalOnMissingBean
-  fun defaultVariableConverter(objectMapper: ObjectMapper): VariableConverter = VariableConverter(objectMapper = objectMapper)
+  fun defaultJacksonVariableConverter(objectMapper: ObjectMapper): VariableConverter
+    = JacksonVariableConverter(objectMapper = objectMapper)
 
   /**
    * Initializes parameter resolver.

spring-boot-starter/src/main/kotlin/dev/bpmcrafters/processengine/worker/configuration/ProcessEngineWorkerDeploymentAutoConfiguration.kt

@@ -12,37 +12,38 @@ import org.springframework.core.io.support.ResourcePatternResolver
 
 /**
  * Auto-configuration for auto-deployment.
+ * 0.5.0
  */
 @AutoConfiguration
 @EnableConfigurationProperties(ProcessEngineWorkerDeploymentProperties::class)
 class ProcessEngineWorkerDeploymentAutoConfiguration {
 
-    /**
-     * Create a process deployment bean, independent of the auto-deployment feature.
-     */
-    @Bean
-    @ConditionalOnMissingBean
-    fun processDeployment(
-        resourcePatternResolver: ResourcePatternResolver,
-        deploymentApi: DeploymentApi,
-        processEngineWorkerDeploymentProperties: ProcessEngineWorkerDeploymentProperties
-    ) = ProcessDeployment(
-        resourcePatternResolver = resourcePatternResolver,
-        deploymentApi = deploymentApi,
-        processEngineWorkerDeploymentProperties = processEngineWorkerDeploymentProperties
-    )
+  /**
+   * Create a process deployment bean, independent of the auto-deployment feature.
+   */
+  @Bean
+  @ConditionalOnMissingBean
+  fun processDeployment(
+    resourcePatternResolver: ResourcePatternResolver,
+    deploymentApi: DeploymentApi,
+    processEngineWorkerDeploymentProperties: ProcessEngineWorkerDeploymentProperties
+  ) = ProcessDeployment(
+    resourcePatternResolver = resourcePatternResolver,
+    deploymentApi = deploymentApi,
+    processEngineWorkerDeploymentProperties = processEngineWorkerDeploymentProperties
+  )
 
-    /**
-     * Configures a trigger for auto-deployment triggered by application start event.
-     */
-    @ConditionalOnProperty(
-        prefix = ProcessEngineWorkerDeploymentProperties.PREFIX,
-        name = ["enabled"],
-        havingValue = "true",
-        matchIfMissing = false
-    )
-    @Bean
-    fun autoDeploymentOnStartup(processDeployment: ProcessDeployment) =
-        AutoDeploymentOnStartup(processDeployment = processDeployment)
+  /**
+   * Configures a trigger for auto-deployment triggered by application start event.
+   */
+  @ConditionalOnProperty(
+    prefix = ProcessEngineWorkerDeploymentProperties.PREFIX,
+    name = ["enabled"],
+    havingValue = "true",
+    matchIfMissing = false
+  )
+  @Bean
+  fun autoDeploymentOnStartup(processDeployment: ProcessDeployment) =
+    AutoDeploymentOnStartup(processDeployment = processDeployment)
 
-}
+}

spring-boot-starter/src/main/kotlin/dev/bpmcrafters/processengine/worker/process/AutoDeploymentOnStartup.kt

@@ -5,6 +5,7 @@ import org.springframework.context.ApplicationListener
 
 /**
  * Trigger to deploy resources on start-up of application.
+ * @since 0.5.0
  */
 class AutoDeploymentOnStartup (
   private val processDeployment: ProcessDeployment

spring-boot-starter/src/main/kotlin/dev/bpmcrafters/processengine/worker/process/ProcessDeployment.kt

@@ -15,37 +15,38 @@ private val logger = KotlinLogging.logger {}
 
 /**
  * Implements configuration of the deployment.
+ * @since 0.5.0
  */
 open class ProcessDeployment(
-    private val resourcePatternResolver: ResourcePatternResolver,
-    private val deploymentApi: DeploymentApi,
-    private val processEngineWorkerDeploymentProperties: ProcessEngineWorkerDeploymentProperties
+  private val resourcePatternResolver: ResourcePatternResolver,
+  private val deploymentApi: DeploymentApi,
+  private val processEngineWorkerDeploymentProperties: ProcessEngineWorkerDeploymentProperties
 ) {
 
-    /**
-     * Deploys resources, configured via properties.
-     */
-    open fun deployResources(): DeploymentInformation? {
-        val namedResources = buildList<Resource> {
-            try {
-                addAll(resourcePatternResolver.getResources(processEngineWorkerDeploymentProperties.bpmnResourcePattern))
-                addAll(resourcePatternResolver.getResources(processEngineWorkerDeploymentProperties.dmnResourcePattern))
-            } catch (e: IOException) {
-                logger.warn(e) { "PROCESS-ENGINE-WORKER-051: Failed to load resources for deployment." }
-            }
-        }.map { resource -> NamedResource(resource.filename ?: "unknown", resource.inputStream) }
-
-        if (namedResources.isEmpty()) {
-            return null
-        }
-
-        return deploymentApi.deploy(
-            DeployBundleCommand(resources = namedResources)
-        ).get(processEngineWorkerDeploymentProperties.deploymentTimeoutInSeconds, TimeUnit.SECONDS)
-            .also { deploymentResult ->
-                logger.info { "PROCESS-ENGINE-WORKER-050: Deployed ${namedResources.size} resources with key ${deploymentResult.deploymentKey}." }
-            }
+  /**
+   * Deploys resources, configured via properties.
+   */
+  open fun deployResources(): DeploymentInformation? {
+    val namedResources = buildList<Resource> {
+      try {
+        addAll(resourcePatternResolver.getResources(processEngineWorkerDeploymentProperties.bpmnResourcePattern))
+        addAll(resourcePatternResolver.getResources(processEngineWorkerDeploymentProperties.dmnResourcePattern))
+      } catch (e: IOException) {
+        logger.warn(e) { "PROCESS-ENGINE-WORKER-051: Failed to load resources for deployment." }
+      }
+    }.map { resource -> NamedResource(resource.filename ?: "unknown", resource.inputStream) }
+
+    if (namedResources.isEmpty()) {
+      return null
     }
+
+    return deploymentApi.deploy(
+      DeployBundleCommand(resources = namedResources)
+    ).get(processEngineWorkerDeploymentProperties.deploymentTimeoutInSeconds, TimeUnit.SECONDS)
+      .also { deploymentResult ->
+        logger.info { "PROCESS-ENGINE-WORKER-050: Deployed ${namedResources.size} resources with key ${deploymentResult.deploymentKey}." }
+      }
+  }
 }
 
 

spring-boot-starter/src/main/kotlin/dev/bpmcrafters/processengine/worker/registrar/JacksonVariableConverter.kt

@@ -0,0 +1,26 @@
+package dev.bpmcrafters.processengine.worker.registrar
+
+import com.fasterxml.jackson.databind.ObjectMapper
+
+/**
+ * Helper converting variables from a JSON map to type using Jackson.
+ * @since 0.0.3
+ */
+open class JacksonVariableConverter(
+  private val objectMapper: ObjectMapper
+) : VariableConverter {
+
+  /**
+   * Reads from the map-tree structure to a target type.
+   * @param value map-tree structure.
+   * @param type target class.
+   * @return cast value.
+   */
+  override fun <T : Any> mapToType(value: Any?, type: Class<T>): T {
+    return if (value != null && !type.isInstance(value)) {
+      objectMapper.readValue(objectMapper.writeValueAsString(value), type)
+    } else {
+      type.cast(value)
+    }
+  }
+}

spring-boot-starter/src/main/kotlin/dev/bpmcrafters/processengine/worker/registrar/ParameterResolutionStrategy.kt

@@ -0,0 +1,26 @@
+package dev.bpmcrafters.processengine.worker.registrar
+
+import dev.bpmcrafters.processengineapi.task.ServiceTaskCompletionApi
+import dev.bpmcrafters.processengineapi.task.TaskInformation
+import java.lang.reflect.Parameter
+import java.util.function.Function
+import java.util.function.Predicate
+
+/**
+ * Parameter resolution strategy.
+ * @since 0.0.1
+ */
+interface ParameterResolutionStrategy : Predicate<Parameter>, Function<ParameterResolutionStrategy.Wrapper, Any?> {
+
+  /**
+   * Wraps parameters of parameter and services for determination of the matching resolution strategy.
+   */
+  data class Wrapper(
+    val parameter: Parameter,
+    val taskInformation: TaskInformation,
+    val payload: Map<String, Any>,
+    val variableConverter: VariableConverter,
+    val taskCompletionApi: ServiceTaskCompletionApi
+  )
+
+}