Special Checks
Introduction
This documents describes special checks in expressions, such as checking whether an object is empty, new, is synced.
Checking for an Empty Object
Checks if an object is empty.
Input Parameters
The input parameters are described in the table below:
| Value | Type |
|---|---|
| An object | Any type of object |
Output
The output is described in the table below:
| Value | Type |
|---|---|
| Returns whether the object is empty | Boolean |
Example
If you use the following input:
$object1 = empty
The output will be False assuming $object1 is a domain entity and that currently exists.
The output will be True if the object does not currently exist (which is possible if you try to retrieve a non-existent object).
The same holds for when $object1 is a variable (such as Integer, String, etc).
Checking for an Empty Object Member
Input Parameters
The input parameters are described in the table below:
| Value | Type |
|---|---|
| A member (attribute or association) of an object | Any type of member |
Output
The output is described in the table below:
| Value | Type |
|---|---|
| Returns whether the attribute is empty | Boolean |
Examples
For example, you have the following input:
$object1/member1 = empty
Assuming $object1 is a domain entity that has a member called ‘member1’, the table below shows the output:
| member1 has a value | member1 does not have a value | |
|---|---|---|
| $object1 has a value | false | true |
| $object1 has no value | N/A | true |
Checking Whether an Object Is New
Checks whether an object is new.
Input Parameters
The input parameters are described in the table below:
| Value | Type |
|---|---|
| An object | Any type of object |
Output
The output is described in the table below:
| Value | Type |
|---|---|
The output depends on whether the object is new (created but not yet committed). Note this only holds when this function is called on a created object. When the object is retrieved from the database isNew will always be false. |
Boolean |
Example
An example of an input can be the following:
isNew($object1)
Checking Whether an Object Is Synced
This function is available only in expressions for conditional visibility or editability and nanoflows, as they are only evaluated on client side.
Input Parameters
The input parameters are described in the table below:
| Value | Type |
|---|---|
| An object | Any type of object |
Output
The output is described in the table below:
| Value | Type |
|---|---|
Returns whether the changes done to the object offline have been synchronized to the runtime database. In web profiles without offline support, this always returns true. |
Boolean |
Example
An example of an input can be the following:
isSynced($currentObject)
Checking If a Synchronization Is Running
This function is available only in client-side expressions (expressions in nanoflows and pages).
Input Parameters
No input parameter is required for this check.
Output
The output is described in the table below:
| Value | Type |
|---|---|
Returns true when there is a synchronization process running, otherwise it returns false. |
Boolean |
Example
An example of an input can be the following:
isSyncing()