new CDA XPATH constants

cda-validation/src/main/java/org/aktin/cda/CDAConstants.java

@@ -40,4 +40,12 @@ public class CDAConstants {
 	 */
 	public static final String XPATH_CDA_PATIENT_ID_EXT = "/cda:ClinicalDocument/cda:recordTarget/cda:patientRole/cda:id/@extension";
 
+	/**
+	 * XPath to CDA encounter root. 
+	 */
+	public static final String XPATH_CDA_ENCOUNTER_ID_ROOT = "/cda:ClinicalDocument/cda:componentOf/cda:encompassingEncounter/cda:id[0]/@root";
+	/**
+	 * XPath to CDA encounter id extension. 
+	 */
+	public static final String XPATH_CDA_ENCOUNTER_ID_EXT= "/cda:ClinicalDocument/cda:componentOf/cda:encompassingEncounter/cda:id[0]/@extension";
 }