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 "ValidationContextFactory.java". Description:
010 "Source of ValidationContext"
011
012 The Initial Developer of the Original Code is University Health Network. Copyright (C)
013 2004. 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 package ca.uhn.hl7v2.validation.impl;
027
028 import ca.uhn.hl7v2.validation.ValidationContext;
029 import ca.uhn.hl7v2.validation.ValidationException;
030
031 /**
032 * <p>Source of <code>ValidationContext</code>. </p>
033 *
034 * <p>The <code>ValidationContext</code> returned by <code>getContext()</code>
035 * is determined by the system property "ca.uhn.hl7v2.validation.context_class".
036 * This factory defines two inner classes that can be used: DefaultValidation
037 * and NoValidation. You can also create your own context, setting whatever rules
038 * you want in its constructor, and reference it instead (it must have a zero-arg
039 * constructor). If this property is not set, DefaultValidation is used. </p>
040 *
041 * <p>Also note that the contexts provided here extend <code>ValidationContextImpl</code>,
042 * so rule bindings can be added or removed programmatically from the starting set. </p>
043 *
044 * @author <a href="mailto:bryan.tripp@uhn.on.ca">Bryan Tripp</a>
045 * @version $Revision: 1.1 $ updated on $Date: 2007-02-19 02:24:40 $ by $Author: jamesagnew $
046 */
047 public class ValidationContextFactory {
048
049 private static ValidationContext ourContext;
050
051 public static final String CONTEXT_PROPERTY = "ca.uhn.hl7v2.validation.context_class";
052
053 private static final ValidationContext NO_VALIDATION = new NoValidation();
054 private static final ValidationContext DEFAULT_VALIDATION = new DefaultValidation();
055
056 /**
057 * Returns a singleton <code>ValidationContext</code>, creating it if necessary.
058 *
059 * @return <code>ValidationContext</code>
060 */
061 public synchronized static ValidationContext getContext() throws ValidationException {
062 if (ourContext == null) {
063 String contextClassName = System.getProperty(CONTEXT_PROPERTY);
064 ourContext = contextClassName == null ?
065 defaultValidation() :
066 customValidation(contextClassName);
067 }
068 return ourContext;
069 }
070
071 public static ValidationContext noValidation() {
072 return NO_VALIDATION;
073 }
074
075 public static ValidationContext defaultValidation() {
076 return DEFAULT_VALIDATION;
077 }
078
079 @SuppressWarnings("unchecked")
080 public static ValidationContext customValidation(String contextClassName) throws ValidationException {
081 try {
082 Class<? extends ValidationContext> c = (Class<? extends ValidationContext>) Class.forName(contextClassName);
083 return c.newInstance();
084 } catch (Exception e) {
085 throw new ValidationException(e);
086 }
087 }
088
089 }