User Task

Introduction

info

A User Task is a typical “workflow” Task where a human performer performs the Task with the assistance of a software application and is scheduled through a task list manager of some sort.

— BPMN 2.0.2 Standard, 10.3.3, User Task

In Flowable, User Tasks are the primary way to interact with humans within a process. Once the execution reaches such a task, a user is required to fill in a form of some sort.

Through forms, it is possible to create and update variables which can be used in other tasks or can be used to control the flow of a process.

Each task can be assigned to one or more people as well as shared with any number of groups. In addition, a task can optionally have a due date.

Example

The following example shows how a process where a user is required to fill a form. The information gathered is used to create an invoice.

A simple corresponding form could look like this:

Properties

General

Common

Attribute	Type	Description	Category
Model Id	Text	Model Id identifies the element within the process model.	The model id, name and documentation properties are used to uniquely identify the user task, to give it a user-friendly name and to add a free-form description. The due date can be used to define a deadline for the task. The priority is a number that is used to indicate its relative importance compared to other tasks. The category can be used to group tasks together and is used in custom queries
Name	Text	The name of the element. This is the name displayed in the diagram.
Documentation	Multiline Text	A free-form text that can be used to explain details about the particular element.
Due date	Date	Due date of the task. It can either be an be an absolute value, a value relative to the creation date or an expression.
Priority	Text	The priority can be be used to sort or categorize tasks. Defaults to priority 50 if left empty.
Category	Text	Category of User Task. This allows you to group user tasks by your own criteria.

Form

Attribute	Type	Description	Category
Form reference	Reference	Reference to the form that will be displayed when opening this task.	Create or link a form to this user task. The form will be shown when the user navigates to the user task and is used to collect data relevant for this user task. A form reference can be unlinked to allow another form to be linked in its place. Note that unlinking a form does not delete the form model itself.
In same deployment	Boolean	Set it to true if the referenced definition should be referenced from within the same app deployment. Set it to false to always use the newest definition.	The Same deployment flag is used to indicate that the user task form model that is used is part of the same app deployment package as where the current BPMN model is in. If unchecked, the latest version is used which can come from an app that is deployed at a later point in time.

Assignment

Attribute	Type	Description	Category
Assignee	User Selection	User ID of the task's assignee. The assignee can see and complete a task and is usually the person responsible for it.	A task needs to be completed by the assignee. This assignee can be a user identifier or you can also use an expression that resolves to the identifier of the user when the process instance is running. The owner of a user task is the identifier - or again an expression- of the user that owns the user task from a business sense, which not necessarily needs to be the same as the assignee.
Owner	User Selection	The ID of the task's owner.
Candidate users	User Selection	By selecting one or more candidate users, the task might be taken by one of those users. If the task is not specifically assigned to one of the users directly, it will show up in all of the selected candidate users tasks list until assigned directly.	Users which are part of the candidate groups can claim this task and take responsibility for completion it. Similarly, candidate users can be set, as a list of user ids or an expression, which identifies the users that can claim this task. Lastly, the task candidates type defines which users will appear in the list of users when changing the assignee of a task.
Candidate groups	Group Selection	By selecting one or more groups as the candidate groups, shares the task with all users belonging to at least one of the groups. If there is no specific assignee specified but the task has candidate groups, the task will show up in all users task list belonging to at least one of the groups until the task is assigned to a specific user.

Multi Instance

Multi instance

Attribute	Type	Description	Category
Multi instance type	Selection: None Parallel Sequential	The type of multi-instance: default is 'None' meaning a single instance is created at runtime. Select either 'Parallel' or 'Sequential' if you want multiple instances to be created.	Multi-instance is used to define the repetition of this user task at runtime. With multi-instance it is possible to have the user tasks multiple times, either sequentially where each user task is created after the previous is completed or in parallel where the user tasks are created all at once and exist concurrently. For example, when referencing a collection one user task is created for each element of that collection.
Collection	Text	References a collection variable (for example a JSON array variable) by its name or using an expression that resolves to a collection.
Element variable	Text	The name of the variable where the currently processed element from the multi-instance collection configured above will be stored (for example, 'invoicePosition'). The element can then be accessed through an expression, e.g., ${invoicePosition}.
Element index variable	Text	The name of the variable where the index of the currently processed item from the multi-instance collection will be stored, for example, 'itemIndex'. The index is a number starting with 0 which is increased with every element that is being created. The index can then be accessed through an expression, e.g., ${itemIndex} further on in the process.
Cardinality	Text	A fixed number or an expression that resolved to an integer that controls the number of instances that will be created. This is typically used when there is no collection available or needed.
Completion condition	Text	An expression that should resolve to a boolean value. When evaluating to true, the remaining activity instances will be removed and the process instance will continue.

Variable aggregation

Attribute	Type	Description	Category
Variable Aggregations	List	Define an aggregation. Each element in this list will result in one aggregation variable.	When using multi-instance, there is often a need to create an aggregation of the variables created and/or updated in each instance. With variable aggregation, a JSON variable can be created that after all instances have been completed contains the summary of all the used variables. This is needed because for multi-instance, variables are persisted locally, to avoid clashes on the process instance level. Alternatively, an 'overview' variable can be created while the instances are still unfinished. Each aggregation consists of one or multiple definitions that map instance variables of one instance of the multi-instance to the aggregation variable.

Advanced

Attribute	Type	Description	Category
Optimize for only automatic steps	Boolean	(Advanced setting, only check it if you understand the implications) If checked, this instructs the Flowable engine that the multi-instance only contains automatic tasks and no wait states. In this situation, an asynchronous job is created when the multi-instance activity is entered that keeps checking if all instances are completed and completes the multi-instance. The benefit of this approach is that it is light on resources versus alternatives and doesn't lead to optimistic locking exceptions.

Advanced Form

Attribute	Type	Description	Category
Form properties	List	Custom form properties which are used within the legacy Flowable form engine or a custom form engine.

Advanced

Execution

Attribute	Type	Description	Category
Skip expression	Text	If the Skip expression evaluates to true, the flow is taken regardless of any condition. It is required to opt-in to this feature by setting a variable _FLOWABLE_SKIP_EXPRESSION_ENABLED with the Boolean value true on the process instance.	The properties on the left are advanced configuration options. The Include in history flag can be used to store the historical entry of this user task when running with a history level that normally would not store the execution of the task. Note that this flag has no effect when running with history level 'none'. When the skip expression resolves to true, this user task will not be executed at runtime. Lastly, the task ID variable allows to store the ID of a user task in a variable on creation.
Include in history	Boolean	When the history level is set to "instance" or "task" level with this property it can be configured if this activity instance should be included in the historic activity data.
Task ID variable	Text	An optional variable that holds the ID of the created task instance.
Is for compensation	Boolean	Determines whether the activity can serve as a compensation for another activity.	The Is for compensation field can be used to indicate that the user task is meant as compensation steps for another activity.
Asynchronous	Boolean	When enabled, the activity will be started as an asynchronous job. The process state is persisted before this element is executed. Then, the process execution will be resumed asynchroneously. This can be used when the execution an activity takes a long time to return the UI to the user quicker in case the user does not need to see the next step immediately. However, if an error occurs before the following wait state, there will be no direct user feedback. Please refer to the documentation for more details.	When making a user task asynchronous, the task will be created asynchronously in the background. This is typically not needed, unless there is heavy-weight logic for example in associated execution- or task listeners.
Exclusive	Boolean	Determines whether the activity or process is run as an exclusive job. An exclusive job makes sure that no other asynchronous exclusive activities within the same process are performed at the same time. This helps to prevent failing jobs in concurrent scenarios.
Leave asynchronously	Boolean	When enabled, the activity will be left as an asynchronous job. This means that the activity is ended asynchronously, including end execution listeners. Please refer to the documentation for more details.
Leave exclusive	Boolean	Determines whether the activity should leave as an exclusive job. An exclusive job makes sure that no other asynchronous exclusive activities within the same process are performed at the same time. This helps to prevent failing jobs in concurrent scenarios.
Job Category	Text	When set, the underlying generated job will have a Job Category, which will be executed only by Application Servers, where the Process Engine has enabledJobCategories set to this category.

Listeners

Attribute	Type	Description	Category
Execution listeners	List	Allows invoking custom after certain lifecycle events. Start: Executes after the activity has been started. End: Executes after the activity was completed. Transition: When defined on a sequence flow, executes once the flow is transition is taken.	Execution listeners are used to add logic on certain lifecycle events. Typically it is used to add extra technical logic which shouldn't be visible in the BPMN process model.
Task listeners	List	Allows you to invoke Java logic after the creation, the reassignment, the completion and the deletion of the task.	Task listeners are used to add logic on certain user task lifecycle events. Typically it is used to add extra technical logic which shouldn't be visible in the BPMN process model.

Visual

Attribute	Type	Description	Category
Background color	Color	The background color of the element in the diagram.	Visual properties that determine how the user task is shown in the diagram. This has no impact on the runtime execution.
Font size	Selection: 8 9 10 11 12 14 18 20 24 36 48 72	Font size.
Font weight	Selection: Normal Bold	Select the style between bold and normal.
Font style	Selection: Normal Italic	Select the style between italic and normal.
Font color	Color	Select a font color.
Border color	Color	The border color of the element in the diagram.

List Attribute Details

Variable Aggregations

Attribute	Type	Description
Target (Variable / Expression)	Text	The name of the target variable or an expression that gives the variable name
Type	Selection: Default Custom	The type of aggregation. Use 'default' to use the standard behavior of creating an aggregation JSON variable. Use 'custom' to define a delegate expression that will handle the aggregation. Please see the documentation for more information.
Delegate Expression	Text	Define a delegateExpression that will resolve to an instance of VariableAggregator (for BPMN) or PlanItemVariableAggregator (for CMMN). This instance will then be responsible for aggregating the variables.
Class	String	A class that implements VariableAggregator (for BPMN) or PlanItemVariableAggregator (for CMMN). This instance will then be responsible for aggregating the variables.
Target variable creation	Selection: Default Create overview variable Store as transient variable	Configures the way the aggregation variable is created. The 'Default' option creates the aggregation variable when all instances of the multi-instance have been completed. Use 'Create overview variable' to create a variable at the start of the multi-instance and keep it up to date during multi-instance exeution. Once all the instances are completed it will create a JSON variable in the same way as for Default target variable creation. Use the 'Store as transient variable' option to have the default behavior, but store the resulting aggregation variable transiently.
Variable Definitions	BasicFormList	property.loopVariableAggregation.definitions.description

Variable Definitions

Attribute	Type	Description
Source (Variable / Expression)	Text	The name of the source variable or an expression that provides the value
Target (Variable / Expression)	Text	The name of the aggregation variable or an expression that resolves to a variable name.

Form properties

Attribute	Type	Description
Id	Text	A unique identifier for this form property.
Name	Text	A name for the form property.
Type	Selection: String Long Boolean Date Enum Custom	The type of the form property
Custom type	Text
Expression	Text	An expression used to determine the value of this form property
Variable	Text	The variable to map the value on to.
Default	Text	The default value if not set (an expression).
Required	Boolean
Readable	Boolean
writable	Boolean
Date pattern	Text	A java-compatible data pattern, such as dd-MMM-yyyy or yyy-MM-dd.
Form values	BasicFormList
Form values	List

Form values

Attribute	Type	Description
Id	Text	Model Id identifies the element within the process model.
Name	Text	The name of the element. This is the name displayed in the diagram.

Form values

Attribute	Type	Description
Id	Text	A unique identifier.
Name	Text	The name of the custom field value.

Execution listeners

Attribute	Type	Description
Event	Selection: Start End Take	The lifecycle event. The 'Take' event is only available for sequence flow.
Class	Text	Fully qualified classname of a class to be invoked when executing the task. The class must implement either JavaDelegate or ActivityBehavior.
Expression	Text	JUEL Expression to be executed when the task is started. Expressions allow you to interact with the backend by calling services, making calculations etc. You can find more information about expressions in the documentation.
Delegate expression	Text	Delegate Expression to be executed when the task is started. A delegate expression must resolve to a Java object, for instance a Spring bean. The object's class must implement either JavaDelegate or ActivityBehavior.
Fields	List

Fields

Attribute	Type	Description
Name	Text	The name of the element. This is the name displayed in the diagram.
String value	Text
Expression	Text	JUEL Expression to be executed when the task is started. Expressions allow you to interact with the backend by calling services, making calculations etc. You can find more information about expressions in the documentation.
String	Text

Task listeners

Attribute	Type	Description
Event	Selection: Create Assignment Complete Delete	The type of event that the listener should listen to.
Class	Text	Fully qualified classname of a class to be invoked when executing the task. The class must implement either JavaDelegate or ActivityBehavior.
Expression	Text	JUEL Expression to be executed when the task is started. Expressions allow you to interact with the backend by calling services, making calculations etc. You can find more information about expressions in the documentation.
Delegate expression	Text	Delegate Expression to be executed when the task is started. A delegate expression must resolve to a Java object, for instance a Spring bean. The object's class must implement either JavaDelegate or ActivityBehavior.
Fields	List

Fields

Attribute	Type	Description
Name	Text	The name of the element. This is the name displayed in the diagram.
String value	Text
Expression	Text	JUEL Expression to be executed when the task is started. Expressions allow you to interact with the backend by calling services, making calculations etc. You can find more information about expressions in the documentation.
String	Text