1 /** 2 The contents of this file are subject to the Mozilla Public License Version 1.1 3 (the "License"); you may not use this file except in compliance with the License. 4 You may obtain a copy of the License at http://www.mozilla.org/MPL/ 5 Software distributed under the License is distributed on an "AS IS" basis, 6 WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License for the 7 specific language governing rights and limitations under the License. 8 9 The Original Code is "EncodingDetector.java". Description: 10 "Detects message encoding (ER7 / XML)" 11 12 The Initial Developer of the Original Code is University Health Network. Copyright (C) 13 2001. All Rights Reserved. 14 15 Contributor(s): ______________________________________. 16 17 Alternatively, the contents of this file may be used under the terms of the 18 GNU General Public License (the "GPL"), in which case the provisions of the GPL are 19 applicable instead of those above. If you wish to allow use of your version of this 20 file only under the terms of the GPL and not to allow others to use your version 21 of this file under the MPL, indicate your decision by deleting the provisions above 22 and replace them with the notice and other provisions required by the GPL License. 23 If you do not delete the provisions above, a recipient may use your version of 24 this file under either the MPL or the GPL. 25 26 */ 27 28 package ca.uhn.hl7v2.parser; 29 30 import java.util.StringTokenizer; 31 32 /** 33 * Detects message encoding (ER7 / XML) without relying on any 34 * external dependencies 35 */ 36 public final class EncodingDetector { 37 38 /** 39 * Non instantiable 40 */ 41 private EncodingDetector() { 42 // nothing 43 } 44 45 /** 46 * Throws an exception if the message is not ER7 encoded 47 * 48 * @param theMessage message to be examined 49 * @throws RuntimeException if message is not ER7-encoded 50 */ 51 public static void assertEr7Encoded(String theMessage) { 52 // quit if the string is too short 53 if (theMessage.length() < 4) 54 throw new RuntimeException("The message is less than 4 characters long"); 55 56 // string should start with "MSH" 57 if (!theMessage.startsWith("MSH")) 58 throw new RuntimeException("The message does not start with MSH"); 59 60 // 4th character of each segment should be field delimiter 61 char fourthChar = theMessage.charAt(3); 62 StringTokenizer st = new StringTokenizer(theMessage, PipeParser.SEGMENT_DELIMITER, false); 63 while (st.hasMoreTokens()) { 64 String x = st.nextToken(); 65 if (x.length() > 0) { 66 if (Character.isWhitespace(x.charAt(0))) 67 x = PipeParser.stripLeadingWhitespace(x); 68 if (x.length() >= 4 && x.charAt(3) != fourthChar) 69 throw new RuntimeException(String.format( 70 "The 4th character should have been a %c, but it was a %c", x.charAt(3), fourthChar)); 71 } 72 } 73 74 // should be at least 11 field delimiters (because MSH-12 is required) 75 int nextFieldDelimLoc = 0; 76 for (int i = 0; i < 11; i++) { 77 nextFieldDelimLoc = theMessage.indexOf(fourthChar, nextFieldDelimLoc + 1); 78 if (nextFieldDelimLoc < 0) 79 throw new RuntimeException("Expected to find required field MSH-12"); 80 } 81 82 } 83 84 /** 85 * Returns true if the message is ER7 (pipe-and-hat) encoded 86 * 87 * @param theMessage message to be examined 88 * @return true if message is ER7-encoded 89 */ 90 public static boolean isEr7Encoded(String theMessage) { 91 try { 92 assertEr7Encoded(theMessage); 93 return true; 94 } catch (Exception e) { 95 return false; 96 } 97 } 98 99 /** 100 * Throws an exception if the message is not XML encoded 101 * 102 * @param theMessage message to be examined 103 * @throws RuntimeException if message is not XML-encoded 104 */ 105 public static void assertXmlEncoded(String theMessage) { 106 if (!theMessage.contains("MSH.1>")) throw new RuntimeException("Expected to find MSH.1"); 107 if (!theMessage.contains("MSH.2>")) throw new RuntimeException("Expected to find MSH.2"); 108 } 109 110 /** 111 * Returns true if the message is XML encoded. Note that this 112 * message does not perform a very robust check, and does not 113 * validate for well-formedness. It is only intended to perform 114 * a simple check for XML vs. ER7 messages. 115 * 116 * @param theMessage message to be examined 117 * @return true if message is XML-encoded 118 */ 119 public static boolean isXmlEncoded(String theMessage) { 120 try { 121 assertXmlEncoded(theMessage); 122 return true; 123 } catch (Exception e) { 124 return false; 125 } 126 } 127 128 129 }