001/**
002The contents of this file are subject to the Mozilla Public License Version 1.1 
003(the "License"); you may not use this file except in compliance with the License. 
004You may obtain a copy of the License at http://www.mozilla.org/MPL/ 
005Software distributed under the License is distributed on an "AS IS" basis, 
006WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License for the 
007specific language governing rights and limitations under the License. 
008
009The Original Code is "Expression.java".  Description: 
010"Expressions used for validation rules" 
011
012The Initial Developer of the Original Code is University Health Network. Copyright (C) 
0132012.  All Rights Reserved. 
014
015Contributor(s): ______________________________________. 
016
017Alternatively, the contents of this file may be used under the terms of the 
018GNU General Public License (the "GPL"), in which case the provisions of the GPL are 
019applicable instead of those above.  If you wish to allow use of your version of this 
020file only under the terms of the GPL and not to allow others to use your version 
021of this file under the MPL, indicate your decision by deleting  the provisions above 
022and replace  them with the notice and other provisions required by the GPL License.  
023If you do not delete the provisions above, a recipient may use your version of 
024this file under either the MPL or the GPL. 
025 */
026package ca.uhn.hl7v2.validation.builder;
027
028
029import ca.uhn.hl7v2.HL7Exception;
030import ca.uhn.hl7v2.Location;
031import ca.uhn.hl7v2.model.Structure;
032
033/**
034 * Expression used to obtain values from a message structure
035 *
036 * @param <T>
037 */
038public interface Expression<T extends Structure> {
039
040        /**
041         * Applies this expression on the structure
042         * 
043         * @param structure HL7 structure to be evaluated
044         * @return the result value
045         * @throws HL7Exception
046         */
047        Object evaluate(T structure) throws HL7Exception;
048
049        /**
050         * Returns the expression description used for describing the Rule this expression
051         * is used in.
052         * 
053         * @return description 
054         */
055        String getDescription();
056
057        /**
058         * Returns the location of the structure to which is expression is applied to
059         * 
060         * @param structure HL7 structure to be located
061         * @return the location of the structure
062         * @throws HL7Exception if the structure refers to an invalid location
063         */
064        Location getLocation(T structure) throws HL7Exception;
065}