Form Processor Filters

Here are a number of use-cases for form processor filters:

• Adding fields before the form is generated.
• Adding calculated fields after the default set of fields have been processed.
• Generating a unique identifier for a field before it's stored in the database.
• Generate XML rendition of the metadata after the form data is stored in the database.
• Check field values before they are stored in the database.

A filter registry is associated with each Form Processor implementation that extends the FilteredFormProcessor class, each registered Filter is then called (within the same transaction) for each request processed by the FormProcessor.

public class TaskFormFilter extends AbstractFilter<WorkflowTask, WorkflowTask> {
    public static final String DUEDATE_READONLY_PROP_NAME = "prop_dueDateReadOnly";

    @Override
    public void beforeGenerate(WorkflowTask workflowTask, List<String> fields, List<String> forcedFields,
                               Form form, Map<String, Object> context) {
        if (workflowTask != null) {
            boolean dueDateReadOnly = false;

            final FieldDefinition dueDateReadOnlyFieldDef = new PropertyFieldDefinition("dueDateReadOnly", "d:boolean");
            dueDateReadOnlyFieldDef.setDataKeyName(DUEDATE_READONLY_PROP_NAME);
            dueDateReadOnlyFieldDef.setProtectedField(true);
            dueDateReadOnlyFieldDef.setLabel("Due Date Read-only");
            form.addFieldDefinition(dueDateReadOnlyFieldDef);
            form.addData(DUEDATE_READONLY_PROP_NAME, dueDateReadOnly);
        }
    }

    @Override
    public void afterGenerate(WorkflowTask workflowTask, List<String> fields, List<String> forcedFields,
                              Form form, Map<String, Object> context) {}

    @Override
    public void beforePersist(WorkflowTask workflowTask, FormData fieldDatas) {}

    @Override
    public void afterPersist(WorkflowTask workflowTask, FormData fieldDatas, WorkflowTask workflowTask1) {}
}

<bean id="org.alfresco.training.repo.form.filter.taskFormFilter"
      class="org.alfresco.training.repo.forms.processor.TaskFormFilter" parent="baseFormFilter">
    <property name="filterRegistry" ref="taskFilterRegistry" />
</bean>

In this case we are using the taskFilterRegistry as we are dealing with a Workflow Task forms that are processed by the TaskFormProcessor. There are other filter registries that you need to use for form filters that deal with objects from content models:

• NodeFormProcessor: use the nodeFilterRegistry
• TypeFormProcessor: use the typeFilterRegistry

public class ContentItemFormFilter extends AbstractFilter<Object, NodeRef> {
    @Override public void beforeGenerate(Object item, List<String> fields, List forcedFields,
                                         Form form, Map<String, Object> context) {}
    @Override public void afterGenerate(Object item, List<String> fields, List forcedFields,
                                        Form form, Map<String, Object> context) {}
    @Override public void beforePersist(Object item, FormData data) {}
    @Override public void afterPersist(Object item, FormData data, NodeRef persistedObject) {}
}

<bean id="org.alfresco.training.repo.form.filter.contentItemFormFilterEdit"
      class="org.alfresco.training.repo.forms.processor.ContentItemFormFilter" parent="baseFormFilter">
    <property name="filterRegistry" ref="nodeFilterRegistry" />
</bean>

<bean id="org.alfresco.training.repo.form.filter.contentItemFormFilterCreate"
      class="org.alfresco.training.repo.forms.processor.ContentItemFormFilter" parent="baseFormFilter">
    <property name="filterRegistry" ref="typeFilterRegistry" />
</bean>

The different methods that can be overridden, such as beforeGenerate, gives you the possibility to hook into the forms processing. They have the following meaning:

• beforeGenerate: Callback invoked before the form is generated/created. This is the place to add properties that should be used by for example form controls.
• afterGenerate: Callback invoked after the form has been generated for the given items and fields.
• beforePersist: Callback invoked before the form data is stored in the database. This method can be used to for example check the form fields.
• afterPersist: Callback invoked after the form data is stored in the database.