| 1 |  |  | <?php | 
            
                                                                                                            
                            
            
                                    
            
            
                | 2 |  |  |  | 
            
                                                                                                            
                            
            
                                    
            
            
                | 3 |  |  | /* | 
            
                                                                                                            
                            
            
                                    
            
            
                | 4 |  |  |  * The MIT License | 
            
                                                                                                            
                            
            
                                    
            
            
                | 5 |  |  |  * | 
            
                                                                                                            
                            
            
                                    
            
            
                | 6 |  |  |  * Copyright 2016 Julien Fastré <[email protected]>. | 
            
                                                                                                            
                            
            
                                    
            
            
                | 7 |  |  |  * | 
            
                                                                                                            
                            
            
                                    
            
            
                | 8 |  |  |  * Permission is hereby granted, free of charge, to any person obtaining a copy | 
            
                                                                                                            
                            
            
                                    
            
            
                | 9 |  |  |  * of this software and associated documentation files (the "Software"), to deal | 
            
                                                                                                            
                            
            
                                    
            
            
                | 10 |  |  |  * in the Software without restriction, including without limitation the rights | 
            
                                                                                                            
                            
            
                                    
            
            
                | 11 |  |  |  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell | 
            
                                                                                                            
                            
            
                                    
            
            
                | 12 |  |  |  * copies of the Software, and to permit persons to whom the Software is | 
            
                                                                                                            
                            
            
                                    
            
            
                | 13 |  |  |  * furnished to do so, subject to the following conditions: | 
            
                                                                                                            
                            
            
                                    
            
            
                | 14 |  |  |  * | 
            
                                                                                                            
                            
            
                                    
            
            
                | 15 |  |  |  * The above copyright notice and this permission notice shall be included in | 
            
                                                                                                            
                            
            
                                    
            
            
                | 16 |  |  |  * all copies or substantial portions of the Software. | 
            
                                                                                                            
                            
            
                                    
            
            
                | 17 |  |  |  * | 
            
                                                                                                            
                            
            
                                    
            
            
                | 18 |  |  |  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR | 
            
                                                                                                            
                            
            
                                    
            
            
                | 19 |  |  |  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, | 
            
                                                                                                            
                            
            
                                    
            
            
                | 20 |  |  |  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE | 
            
                                                                                                            
                            
            
                                    
            
            
                | 21 |  |  |  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER | 
            
                                                                                                            
                            
            
                                    
            
            
                | 22 |  |  |  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, | 
            
                                                                                                            
                            
            
                                    
            
            
                | 23 |  |  |  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN | 
            
                                                                                                            
                            
            
                                    
            
            
                | 24 |  |  |  * THE SOFTWARE. | 
            
                                                                                                            
                            
            
                                    
            
            
                | 25 |  |  |  */ | 
            
                                                                                                            
                            
            
                                    
            
            
                | 26 |  |  |  | 
            
                                                                                                            
                            
            
                                    
            
            
                | 27 |  |  | namespace PHPHealth\CDA\Elements; | 
            
                                                                                                            
                            
            
                                    
            
            
                | 28 |  |  |  | 
            
                                                                                                            
                            
            
                                    
            
            
                | 29 |  |  | use PHPHealth\CDA\DataType\Quantity\DateAndTime\TimeStamp; | 
            
                                                                                                            
                            
            
                                    
            
            
                | 30 |  |  | use PHPHealth\CDA\DataType\Collection\Interval\PeriodicIntervalOfTime; | 
            
                                                                                                            
                            
            
                                    
            
            
                | 31 |  |  | use PHPHealth\CDA\ClinicalDocument as CDA; | 
            
                                                                                                            
                            
            
                                    
            
            
                | 32 |  |  |  | 
            
                                                                                                            
                            
            
                                    
            
            
                | 33 |  |  | /** | 
            
                                                                                                            
                            
            
                                    
            
            
                | 34 |  |  |  * | 
            
                                                                                                            
                            
            
                                    
            
            
                | 35 |  |  |  * | 
            
                                                                                                            
                            
            
                                    
            
            
                | 36 |  |  |  * @author Julien Fastré <[email protected]> | 
            
                                                                                                            
                            
            
                                    
            
            
                | 37 |  |  |  */ | 
            
                                                                                                            
                            
            
                                    
            
            
                | 38 |  |  | class EffectiveTime extends AbstractElement | 
            
                                                                                                            
                            
            
                                    
            
            
                | 39 |  |  | { | 
            
                                                                                                            
                            
            
                                    
            
            
                | 40 |  |  |     /** | 
            
                                                                                                            
                            
            
                                    
            
            
                | 41 |  |  |      * | 
            
                                                                                                            
                            
            
                                    
            
            
                | 42 |  |  |      * @var TimeStamp|PeriodicIntervalOfTime | 
            
                                                                                                            
                            
            
                                    
            
            
                | 43 |  |  |      */ | 
            
                                                                                                            
                            
            
                                    
            
            
                | 44 |  |  |     protected $value; | 
            
                                                                                                            
                            
            
                                    
            
            
                | 45 |  |  |      | 
            
                                                                                                            
                            
            
                                    
            
            
                | 46 |  |  |     /** | 
            
                                                                                                            
                            
            
                                    
            
            
                | 47 |  |  |      * | 
            
                                                                                                            
                            
            
                                    
            
            
                | 48 |  |  |      * @var string | 
            
                                                                                                            
                            
            
                                    
            
            
                | 49 |  |  |      */ | 
            
                                                                                                            
                            
            
                                    
            
            
                | 50 |  |  |     protected $operator = ''; | 
            
                                                                                                            
                            
            
                                    
            
            
                | 51 |  |  |      | 
            
                                                                                                            
                            
            
                                    
            
            
                | 52 |  |  |     public function __construct($value) | 
            
                                                                                                            
                            
            
                                    
            
            
                | 53 |  |  |     { | 
            
                                                                                                            
                            
            
                                    
            
            
                | 54 |  |  |         $this->setValue($value); | 
            
                                                                                                            
                            
            
                                    
            
            
                | 55 |  |  |     } | 
            
                                                                                                            
                            
            
                                    
            
            
                | 56 |  |  |      | 
            
                                                                                                            
                            
            
                                    
            
            
                | 57 |  |  |      | 
            
                                                                                                            
                            
            
                                    
            
            
                | 58 |  |  |     public function getValue() | 
            
                                                                                                            
                            
            
                                    
            
            
                | 59 |  |  |     { | 
            
                                                                                                            
                            
            
                                    
            
            
                | 60 |  |  |         return $this->value; | 
            
                                                                                                            
                            
            
                                    
            
            
                | 61 |  |  |     } | 
            
                                                                                                            
                            
            
                                    
            
            
                | 62 |  |  |  | 
            
                                                                                                            
                            
            
                                    
            
            
                | 63 |  |  |     public function setValue($value) | 
            
                                                                                                            
                            
            
                                    
            
            
                | 64 |  |  |     { | 
            
                                                                                                            
                            
            
                                    
            
            
                | 65 |  |  |         if ($value instanceof PeriodicIntervalOfTime || | 
            
                                                                                                            
                            
            
                                    
            
            
                | 66 |  |  |             $value instanceof TimeStamp) { | 
            
                                                                                                            
                            
            
                                    
            
            
                | 67 |  |  |             $this->value = $value; | 
            
                                                                                                            
                            
            
                                    
            
            
                | 68 |  |  |         } else { | 
            
                                                                                                            
                            
            
                                    
            
            
                | 69 |  |  |             throw new \UnexpectedValueException(sprintf("The timestamp must " | 
            
                                                                                                            
                            
            
                                    
            
            
                | 70 |  |  |                 . "implements %s or %s", PeriodicIntervalOfTime::class,  | 
            
                                                                                                            
                            
            
                                    
            
            
                | 71 |  |  |                 TimeStamp::class)); | 
            
                                                                                                            
                            
            
                                    
            
            
                | 72 |  |  |         } | 
            
                                                                                                            
                            
            
                                    
            
            
                | 73 |  |  |          | 
            
                                                                                                            
                            
            
                                    
            
            
                | 74 |  |  |         return $this; | 
            
                                                                                                            
                            
            
                                    
            
            
                | 75 |  |  |     } | 
            
                                                                                                            
                                                                
            
                                    
            
            
                | 76 |  |  |      | 
            
                                                                        
                            
            
                                    
            
            
                | 77 |  |  |     public function setOperatorAppend() | 
            
                                                                        
                            
            
                                    
            
            
                | 78 |  |  |     { | 
            
                                                                        
                            
            
                                    
            
            
                | 79 |  |  |         $this->operator = 'A'; | 
            
                                                                        
                            
            
                                    
            
            
                | 80 |  |  |     } | 
            
                                                                                                            
                            
            
                                    
            
            
                | 81 |  |  |  | 
            
                                                                                                            
                            
            
                                    
            
            
                | 82 |  |  |     public function toDOMElement(\DOMDocument $doc) | 
            
                                                                                                            
                            
            
                                    
            
            
                | 83 |  |  |     { | 
            
                                                                                                            
                            
            
                                    
            
            
                | 84 |  |  |         $el = $this->createElement($doc, ['value']); | 
            
                                                                                                            
                            
            
                                    
            
            
                | 85 |  |  |          | 
            
                                                                                                            
                            
            
                                    
            
            
                | 86 |  |  |         if ($this->operator === 'A') { | 
            
                                                                                                            
                            
            
                                    
            
            
                | 87 |  |  |             $el->setAttribute(CDA::NS_CDA.'operator', 'A'); | 
            
                                                                                                            
                            
            
                                    
            
            
                | 88 |  |  |         } | 
            
                                                                                                            
                            
            
                                    
            
            
                | 89 |  |  |          | 
            
                                                                                                            
                            
            
                                    
            
            
                | 90 |  |  |         return $el; | 
                            
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                | 91 |  |  |     } | 
            
                                                                                                            
                            
            
                                    
            
            
                | 92 |  |  |  | 
            
                                                                                                            
                            
            
                                    
            
            
                | 93 |  |  |     protected function getElementTag() | 
            
                                                                                                            
                            
            
                                    
            
            
                | 94 |  |  |     { | 
            
                                                                                                            
                            
            
                                    
            
            
                | 95 |  |  |         return 'effectiveTime'; | 
            
                                                                                                            
                            
            
                                    
            
            
                | 96 |  |  |     } | 
            
                                                                                                            
                                                                
            
                                    
            
            
                | 97 |  |  | } | 
            
                                                        
            
                                    
            
            
                | 98 |  |  |  | 
            
                        
If you return a value from a function or method, it should be a sub-type of the type that is given by the parent type f.e. an interface, or abstract method. This is more formally defined by the Lizkov substitution principle, and guarantees that classes that depend on the parent type can use any instance of a child type interchangably. This principle also belongs to the SOLID principles for object oriented design.
Let’s take a look at an example:
Our function
my_functionexpects aPostobject, and outputs the author of the post. The base classPostreturns a simple string and outputting a simple string will work just fine. However, the child classBlogPostwhich is a sub-type ofPostinstead decided to return anobject, and is therefore violating the SOLID principles. If aBlogPostwere passed tomy_function, PHP would not complain, but ultimately fail when executing thestrtouppercall in its body.