001 /**
002 The 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.
004 You may obtain a copy of the License at http://www.mozilla.org/MPL/
005 Software distributed under the License is distributed on an "AS IS" basis,
006 WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License for the
007 specific language governing rights and limitations under the License.
008
009 The Original Code is "GroupPointer.java". Description:
010 "A GroupPointer is used when parsing traditionally encoded HL7 messages"
011
012 The Initial Developer of the Original Code is University Health Network. Copyright (C)
013 2001. All Rights Reserved.
014
015 Contributor(s): ______________________________________.
016
017 Alternatively, the contents of this file may be used under the terms of the
018 GNU General Public License (the "GPL"), in which case the provisions of the GPL are
019 applicable instead of those above. If you wish to allow use of your version of this
020 file only under the terms of the GPL and not to allow others to use your version
021 of this file under the MPL, indicate your decision by deleting the provisions above
022 and replace them with the notice and other provisions required by the GPL License.
023 If you do not delete the provisions above, a recipient may use your version of
024 this file under either the MPL or the GPL.
025
026 */
027
028 package ca.uhn.hl7v2.parser;
029
030 import java.util.StringTokenizer;
031
032 /**
033 * Detects message encoding (ER7 / XML) without relying on any
034 * external dependencies
035 */
036 public class EncodingDetector {
037
038 /**
039 * Non instantiable
040 */
041 private EncodingDetector() {
042 // nothing
043 }
044
045 /**
046 * Returns true if the message is ER7 (pipe-and-hat) encoded
047 */
048 public static boolean isEr7Encoded(String theMessage) {
049 // quit if the string is too short
050 if (theMessage.length() < 4)
051 return false;
052
053 // see if it looks like this message is | encoded ...
054 boolean ok = true;
055
056 // string should start with "MSH"
057 if (!theMessage.startsWith("MSH"))
058 return false;
059
060 // 4th character of each segment should be field delimiter
061 char fourthChar = theMessage.charAt(3);
062 StringTokenizer st = new StringTokenizer(theMessage, String.valueOf(PipeParser.SEGMENT_DELIMITER), false);
063 while (st.hasMoreTokens()) {
064 String x = st.nextToken();
065 if (x.length() > 0) {
066 if (Character.isWhitespace(x.charAt(0)))
067 x = PipeParser.stripLeadingWhitespace(x);
068 if (x.length() >= 4 && x.charAt(3) != fourthChar)
069 return false;
070 }
071 }
072
073 // should be at least 11 field delimiters (because MSH-12 is required)
074 int nextFieldDelimLoc = 0;
075 for (int i = 0; i < 11; i++) {
076 nextFieldDelimLoc = theMessage.indexOf(fourthChar, nextFieldDelimLoc + 1);
077 if (nextFieldDelimLoc < 0)
078 return false;
079 }
080
081 return ok;
082 }
083
084
085 /**
086 * Returns true if the message is XML encoded. Note that this
087 * message does not perform a very robust check, and does not
088 * validate for well-formedness. It is only intended to perform
089 * a simple check for XML vs. ER7 messages.
090 */
091 public static boolean isXmlEncoded(String theMessage) {
092 //check for a number of expected strings
093 String[] expected = { "<MSH.1", "<MSH.2", "</MSH>" };
094 for (int i = 0; i < expected.length; i++) {
095 if (theMessage.indexOf(expected[i]) < 0) {
096 return false;
097 }
098 }
099
100 return true;
101 }
102
103
104 }