How to retrieve a file name stored in WCM library file resource component using the API ReferenceComponent

finds the document id of the content items that match by name 
DocumentIdIterator docIdIterator = ws.findByName(DocumentTypes.Content, "testcontent");
DocumentId docId;
Content currentContent; 


loops through the document id's found in the iterator
while(docIdIterator.hasNext()) 
{
docId = (DocumentId)docIdIterator.next();

get the current content item
currentContent = (Content)ws.getById(docId); 

standard out log message
System.out.println("Log: Testing WCM API: Retrieved content name = " 
+ (String)currentContent.getName());

get the content's component reference element by name
ContentComponent myCmpnt = 
(ContentComponent) currentContent.getComponent("MyComponent");

standard out log message
System.out.println("Log: Testing WCM API: My Component getName = " 
+ (String)myCmpnt.getName());

Typecast using ReferenceComponent in order to access the library component 
stored in the content's component reference element

ReferenceComponent myRefCmpnt;
myRefCmpnt = (ReferenceComponent)myCmpnt;

Get the LibraryComponent which your content is referencing 
LibraryComponent myLibCmpnt = myRefCmpnt.getComponentRef() ;

standard out log message
System.out.println("Log: Testing WCM API: My Library Component name = " 
+ myLibCmpnt.getName());

Use the instanceof method to confirm the library component type. 
For example, this checks if your component is a Library File Component.

if (myLibCmpnt instanceof LibraryFileComponent)
{

In this example, the component reference holds a LibraryFileComponent. 
This will get the file name of the file stored in the LibraryFileComponent.
LibraryFileComponent fileCmpnt;
fileCmpnt= (LibraryFileComponent)myLibCmpnt;

standard out log message
System.out.println("Log: Testing WCM API: My Library File Component: File name = " 
+ fileCmpnt.getFileName() );
} end if statement