public java.util.List<String> getStandardIdentifiers() {
        return standardIdentifiers;
    }
<p>
The types of keys that a ProfileObject can have. Each ProfileObject can have only 1 UNIQUE key but multiple
PROFILE keys. PROFILE, ASSET, CASE, or ORDER means that this key can be used to tie an object to a PROFILE,
ASSET, CASE, or ORDER respectively. UNIQUE means that it can be used to uniquely identify an object. If a key a
is marked as SECONDARY, it will be used to search for profiles after all other PROFILE keys have been searched. A
LOOKUP_ONLY key is only used to match a profile but is not persisted to be used for searching of the profile. A
NEW_ONLY key is only used if the profile does not already exist before the object is ingested, otherwise it is
only used for matching objects to profiles.
</p>

@return The types of keys that a ProfileObject can have. Each ProfileObject can have only 1 UNIQUE key but
        multiple PROFILE keys. PROFILE, ASSET, CASE, or ORDER means that this key can be used to tie an object to
        a PROFILE, ASSET, CASE, or ORDER respectively. UNIQUE means that it can be used to uniquely identify an
        object. If a key a is marked as SECONDARY, it will be used to search for profiles after all other PROFILE
        keys have been searched. A LOOKUP_ONLY key is only used to match a profile but is not persisted to be
        used for searching of the profile. A NEW_ONLY key is only used if the profile does not already exist
        before the object is ingested, otherwise it is only used for matching objects to profiles.
@see StandardIdentifier
aws-java-sdk-customerprofiles/src/main/java/com/amazonaws/services/customerprofiles/model/ObjectTypeKey.java