001package org.hl7.fhir.dstu2.model;
002
003/*-
004 * #%L
005 * org.hl7.fhir.dstu2
006 * %%
007 * Copyright (C) 2014 - 2019 Health Level 7
008 * %%
009 * Licensed under the Apache License, Version 2.0 (the "License");
010 * you may not use this file except in compliance with the License.
011 * You may obtain a copy of the License at
012 * 
013 *      http://www.apache.org/licenses/LICENSE-2.0
014 * 
015 * Unless required by applicable law or agreed to in writing, software
016 * distributed under the License is distributed on an "AS IS" BASIS,
017 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
018 * See the License for the specific language governing permissions and
019 * limitations under the License.
020 * #L%
021 */
022
023
024/*
025Copyright (c) 2011+, HL7, Inc.
026All rights reserved.
027
028Redistribution and use in source and binary forms, with or without modification, 
029are permitted provided that the following conditions are met:
030
031 * Redistributions of source code must retain the above copyright notice, this 
032   list of conditions and the following disclaimer.
033 * Redistributions in binary form must reproduce the above copyright notice, 
034   this list of conditions and the following disclaimer in the documentation 
035   and/or other materials provided with the distribution.
036 * Neither the name of HL7 nor the names of its contributors may be used to 
037   endorse or promote products derived from this software without specific 
038   prior written permission.
039
040THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND 
041ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED 
042WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 
043IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, 
044INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 
045NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR 
046PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, 
047WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 
048ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 
049POSSIBILITY OF SUCH DAMAGE.
050
051*/
052
053/**
054 * This class is created to help implementers deal with a change to 
055 * the API that was made between versions 0.81 and 0.9
056 * 
057 *  The change is the behaviour of the .getX() where the cardinality of 
058 *  x is 0..1 or 1..1. Before the change, these routines would return 
059 *  null if the object had not previously been assigned, and after the '
060 *  change, they will automatically create the object if it had not 
061 *  been assigned (unless the object is polymorphic, in which case, 
062 *  only the type specific getters create the object)
063 *  
064 *  When making the transition from the old style to the new style, 
065 *  the main change is that when testing for presence or abssense
066 *  of the element, instead of doing one of these two: 
067 *  
068 *    if (obj.getProperty() == null)
069 *    if (obj.getProperty() != null)
070 *    
071 *  you instead do 
072 *  
073 *    if (!obj.hasProperty())
074 *    if (obj.hasProperty())
075 *    
076 * or else one of these two:
077 *    
078 *    if (obj.getProperty().isEmpty())
079 *    if (!obj.getProperty().isEmpty())
080 * 
081 * The only way to sort this out is by finding all these things 
082 * in the code, and changing them. 
083 * 
084 * To help with that, you can set the status field of this class
085 * to change how this API behaves. Note: the status value is tied
086 * to the way that you program. The intent of this class is to 
087 * help make developers the transiition to status = 0. The old
088 * behaviour is status = 2. To make the transition, set the 
089 * status code to 1. This way, any time a .getX routine needs
090 * to automatically create an object, an exception will be 
091 * raised instead. The expected use of this is:
092 *   - set status = 1
093 *   - test your code (all paths) 
094 *   - when an exception happens, change the code to use .hasX() or .isEmpty()
095 *   - when all execution paths don't raise an exception, set status = 0
096 *   - start programming to the new style. 
097 * 
098 * You can set status = 2 and leave it like that, but this is not 
099 * compatible with the utilities and validation code, nor with the
100 * HAPI code. So everyone shoul make this transition
101 *  
102 * This is a difficult change to make to an API. Most users should engage with it
103 * as they migrate from DSTU1 to DSTU2, at the same time as they encounter 
104 * other changes. This change was made in order to align the two java reference 
105 * implementations on a common object model, which is an important outcome that
106 * justifies making this change to implementers (sorry for any pain caused)
107 *  
108 * @author Grahame
109 *
110 */
111public class Configuration {
112
113        private static int status = 0;
114          // 0: auto-create  
115          // 1: error
116          // 2: return null
117
118        public static boolean errorOnAutoCreate() {
119          return status == 1;
120  }
121
122
123        public static boolean doAutoCreate() {
124          return status == 0;
125  }
126
127}