How Jira plugin custom field value gets processed on the way to .vm templates

问题

Jira server 7.2.1. Custom field plugin.

The question follows this discussion Can't understand, what does method getSingularObjectFromString do? and some info from "Practical jira plugins"

I'm trying to implement a database custom field with basic value-displayValue logic. The field represents an external entity, so I'm storing ID as a value of the field, but displaying NAME. I have two .vm templates: edit and view. I'm trying to choose the right place to convert ID to NAME. I've overridden a method getStringFromSingularObject(Object o) to get the NAME from ID. It works absolutely fine in edit.vm. As a $value variable I get exactly the name, but in view.vm I still get an id as a $value. I've logged the method calls for the method for AbstractSingleFieldType and noticed that

1. when the page with my field gets rendered: Methods getValueFromIssue, getDatabaseType, getObjectFromDbValue are being called 4 times each (4 cycles in that order). So they are definitely not the place for a query.

2. when the field is rendered in the edit mode (so the edit.vm is processed) (i.e. create screen or edit screen, : the same methods are called 4 times and then getStringFromSingularObject and getStringValueFromCustomFieldParams are called and they return the name that I want.

3. when I simply refresh the view issue screen: The method getStringFromSingularObject doesn't get called at all - the source of my problem.

4. currently in the view issue screen I see ID instead of the name, but when I click on the pencil (edit) I see the right value (the name). Moreover, in that case none of the methods are called. So I guess Jira processes both templates beforehand?

edit.vm

<div class="field-group">
    <label for="cFieldId">
        $customField.name $value
        #if($fieldLayoutItem.required)
            <span class="aui-icon icon-required">Required</span>
        #end
    </label>
    <select class="select cf-select" name="$customField.id" id="$customField.id">
        <option value="">None</option>
        #foreach ($id in $items.keySet())
            #if ($value && $value.equals($items.get($id)))
                <option value="$id" selected="selected">$items.get($id)</option>
            #else
                <option value="$id">$items.get($id)</option>
            #end
        #end
    </select>
</div>

view.vm

<div id="$customField.id-val" class="value type-select" data-fieldtype="select" data-fieldtypecompletekey="com.atlassian.jira.plugin.system.customfieldtypes:select">
    $value
</div>

Once again, edit.vm works fine displaying name as a value and names as options. view.vm works wrong, displaying id. So, the questions are:

1. why the method, that is kind of responsible for displaying a value doesn't get called on view?
2. where the $value is really getting set for the view.vm
3. what other options do I have for my purposes

来源：https://stackoverflow.com/questions/39703254/how-jira-plugin-custom-field-value-gets-processed-on-the-way-to-vm-templates