Actions

In previous chapter we have checked about the object views. The views however requires actions to do something useful other then just CRUD operations.

The actions are also defined using xml and can be used to change views, objects, call controllers or doing some specific tasks like sending email, importing remote data etc.

In this chapter we’ll see different kind of actions.

Concepts

Actions can be used to perform some advanced operations on the view, including:

  • providing default values

  • changing form values

  • changing field attributes

  • calling controller methods

  • validating current record

Actions are re-usable. So each action should be given an unique name.

Events

Actions can be performed on various events. These includes:

  • onNew - when creating new record

  • onLoad - when record is loaded in form view

  • onSave - when record is about to save

  • onChange - when a field value is changed

  • onSelect - when select record button is clicked (relational fields only)

  • onClick - when a field/button is clicked

Context

The context is a map of key-value pair of the current object being edited. The context may contain some extra information like _parent context. Also, the values of multi-value fields (O2M/M2M) are marked with _selected flag to check whether the record is selected or not.

Expressions

The xml actions uses dynamic expressions to access object values or conditional test expressions to enable/disable actions.

An expression is either a:

  • groovy expression - prefixed with eval:

  • select expression - JPQL select queries, prefixed with select:

  • action expression - another action, prefixed with action:

  • call expression - call a method, prefixed with call:

  • constant expression - the expression is considered as constant value

These expressions can be defined in groovy or Java EL syntax. The Java EL support has been added in v4.0.

We can mix both expression syntax in same action definition. The rules are:

  1. the eval: expressions are considered groovy expressions

  2. the select: expressions are considered Java EL expression

  3. expression wrapped inside #{…​} are considered Java EL expression

The rules in details:

  • expr="eval: …​" - use groovy

  • expr="select: …​" - use EL

  • expr="#{…​}" - use EL

  • expr="…​" - return as it is (constant)

  • search="…​" - search expression on action-record are handled with EL

  • if="#{…​}" - use EL

  • if="eval: …​" - use groovy

  • if="select: …​" - use EL

  • if="…​" - use groovy

The EL expressions can use following predefined helper functions:

  • is(Object, Class) - check whether the given object is instance of the the class

  • as(Object, Class) - cast the object as the given class (generally, casting is automatic in EL but useful to convert context to a model class)

  • str(Object) - convert object to string (if null, returns empty string "")

  • imp(String) - import a class by name

  • repo(Class) - get the repository of the given model class

  • fmt:text(String, Object…​) - string format helper

Some examples:

<action-attrs name="action-test">
    <attribute ... if="code == 'some'" expr="eval: __self__?.customer?.fullName" /> (1)
    <attribute ... if="#{code == 'some'}" expr="#{ __self__.customer.fullName }" /> (2)
    <attribute ... expr="call: com.axelor.contact.SomeController:method" /> (3)
    <attribute ... expr="select: s.fullName from Contact s where s.code = :code" /> (4)
</action-attrs>
1 standard groovy expressions
2 Java EL expression needs to be wrapped inside #{…​}, also no need of null value check
3 call: expressions are handled with JavaEL
4 select: expressions are handled with JavaEL

We are using Java EL 3.0 (from tomcat8). See the Java EL documentation for more details.

Built-ins variables

Some built-in variables have been provided to use with expressions. These includes:

  • __date__ - current date

  • __time__ - current datetime

  • __datetime__ - current datetime

  • __user__ - current user

  • __this__ - the record being edited (representing form values)

  • __self__ - the corresponding record from the database

  • __parent__ - the parent record

  • __ref__ - the selected record in multi-object search view

Special actions

The following special actions can be used to perform some special operations:

  • sync - to sync record, can be used at the beginning or end only

  • save - to save record, can be used anywhere

  • new - start a new record, can be used at the end only

  • close - close current view, can be used at the end only

  • validate - validate current form, can be used any where

For example:

<form ...>
    ...
    <!-- save current form before executing some-action,
         and save again at the end -->
    <field name="some" onChange="save,some-action,another-action,save" />
    ...
    <!-- close current view after action is complete -->
    <field name="some" onChange="some-action,close" />
</form>