How to create dynamic dropdown from folder names in alfresco? - alfresco

Question

I have a task in which I have to present a drop down with client names while uploading a document of a particular type. The names of the client are tied to folders in a given site.
For e.g. Let say I have a site XYZ in alfresco and I have 10 folder with names Client 1 to Client 10 all on the same level, now while uploading the doc the client name field should be populated by the names of the folder present in the site.
I have created a custom java class that will fetch the folder names and place a constraint on the client name in the custom-model.xml file. I was able to show the hard-coded data as a dropdown but now I want the data to be fetched dynamically.
As I am new to alfresco I don't have enough idea how to get it done. I am trying to use Alfresco public java api and CMIS but not able to get anywhere.
Any help on this will be extremely helpful.
Here is the code.
model.xml
<!-- For client name -->
<constraint name="ev:clientNames" type="com.eisenvault.repo.dictionary.constraint.ClientNameConstraint">
<parameter name="allowedValues">
<list>
<value></value>
<!-- Will be empty -->
</list>
</parameter>
</constraint>
ClientNameConstraint.java
import java.io.Serializable;
import java.util.Arrays;
import java.util.Collections;
import java.util.List;
import org.alfresco.repo.dictionary.constraint.ListOfValuesConstraint;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
public class ClientNameConstraint extends ListOfValuesConstraint implements Serializable {
/**
*
*/
private static final long serialVersionUID = 1L;
Log log = LogFactory.getLog(ClientNameConstraint.class);
private List<String> allowedValues;
protected boolean caseSensitive;
protected boolean sorted;
public ClientNameConstraint(){
caseSensitive = true;
sorted = false;
allowedValues = Collections.emptyList();
}
#Override
public List<String> getAllowedValues() {
allowedValues = Arrays.asList("Client1", "Client2", "Client3", "Client4", "Client5", "Client6");
Collections.sort(allowedValues);
super.setAllowedValues(allowedValues);
return allowedValues;
}
#Override
public void initialize() {
System.out.println("Initialized called in ClientNameConstraint....................................");
super.initialize();
checkPropertyNotNull(ALLOWED_VALUES_PARAM, allowedValues);
}
}

Answer 1

I would avoid using a constraint in this case. Others may disagree, but a dynamic constraint could be more trouble than it is worth. This is because you can get integrity exceptions which could be messy to deal with if your client list ever gets out of sync. Imagine if you create some documents with one version of the list, but then delete a folder. Now any operation on those documents will throw an integrity exception.
I personally would create a webscript (it could be in Javascript if you like) which reads out the folders and returns them as JSON. Then, I would create a custom share component and configure my form to use this component. The component would build the list of vales from your webscript but would not depend on a constraint.
It's "more" development than your original idea, but it's more flexible and you won't have any issues with upgrades, etc, if your client folders get out of sync with the content.