sPFShared/src/main/java/it/polimi/spf/shared/model/ProfileField.java
public static String[] toIdentifierList(ProfileField<?>[] fields) {
		if (fields == null) {
			return null;
		}

		String[] identifiers = new String[fields.length];
		for (int i = 0; i < fields.length; i++) {
			identifiers[i] = fields[i].getIdentifier();
		}

		return identifiers;
	}
public static String[] toIdentifierList(ProfileField<?>[] fields) {
		if (fields == null) {
			return null;
		}

		String[] identifiers = new String[fields.length];
		for (int i = 0; i < fields.length; i++) {
			identifiers[i] = fields[i].getIdentifier();
		}

		return identifiers;
	}
Converts an array of {@link ProfileField} to an array of String,
containing the identifier of the original fields, in the same order.

@param fields
- the array to convert
@return the array of identifiers