Complex classes like SystemProperties often do a lot of different things. To break such a class down, we need to identify a cohesive component within that class. A common approach to find such a component is to look for fields/methods that share the same prefixes, or suffixes. You can also have a look at the cohesion graph to spot any un-connected, or weakly-connected components.
Once you have determined the fields that belong together, you can apply the Extract Class refactoring. If the component makes sense as a sub-class, Extract Subclass is also a candidate, and is often faster.
While breaking up the class, it is a good idea to analyze how other classes use SystemProperties, and based on these observations, apply Extract Interface, too.
| 1 | <?php  | 
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| 55 | class SystemProperties extends AbstractProperties  | 
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| 56 | { | 
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| 57 | /**  | 
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| 58 | * Collection name  | 
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| 59 | *  | 
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| 60 | * @var string  | 
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| 61 | */  | 
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| 62 | const COLLECTION = 'system';  | 
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| 63 | /**  | 
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| 64 | * ID property  | 
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| 65 | *  | 
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| 66 | * @var string  | 
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| 67 | */  | 
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| 68 | const PROPERTY_ID = 'id';  | 
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| 69 | /**  | 
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| 70 | * Type property  | 
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| 71 | *  | 
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| 72 | * @var string  | 
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| 73 | */  | 
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| 74 | const PROPERTY_TYPE = 'type';  | 
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| 75 | /**  | 
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| 76 | * Revision property  | 
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| 77 | *  | 
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| 78 | * @var string  | 
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| 79 | */  | 
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| 80 | const PROPERTY_REVISION = 'revision';  | 
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| 81 | /**  | 
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| 82 | * Created property  | 
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| 83 | *  | 
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| 84 | * @var string  | 
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| 85 | */  | 
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| 86 | const PROPERTY_CREATED = 'created';  | 
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| 87 | /**  | 
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| 88 | * Modified property  | 
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| 89 | *  | 
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| 90 | * @var string  | 
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| 91 | */  | 
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| 92 | const PROPERTY_MODIFIED = 'modified';  | 
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| 93 | /**  | 
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| 94 | * Published property  | 
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| 95 | *  | 
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| 96 | * @var string  | 
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| 97 | */  | 
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| 98 | const PROPERTY_PUBLISHED = 'published';  | 
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| 99 | /**  | 
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| 100 | * Deleted property  | 
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| 101 | *  | 
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| 102 | * @var string  | 
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| 103 | */  | 
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| 104 | const PROPERTY_DELETED = 'deleted';  | 
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| 105 | /**  | 
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| 106 | * Language property  | 
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| 107 | *  | 
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| 108 | * @var string  | 
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| 109 | */  | 
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| 110 | const PROPERTY_LANGUAGE = 'language';  | 
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| 111 | /**  | 
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| 112 | * Location property  | 
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| 113 | *  | 
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| 114 | * @var string  | 
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| 115 | */  | 
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| 116 | const PROPERTY_LOCATION = 'location';  | 
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| 117 | /**  | 
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| 118 | * Object ID (constant throughout revisions)  | 
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| 119 | *  | 
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| 120 | * @var Id  | 
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| 121 | */  | 
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| 122 | protected $uid = null;  | 
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| 123 | /**  | 
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| 124 | * Object type (constant throughout revisions)  | 
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| 125 | *  | 
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| 126 | * @var Type  | 
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| 127 | */  | 
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| 128 | protected $type = null;  | 
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| 129 | /**  | 
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| 130 | * Object revision  | 
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| 131 | *  | 
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| 132 | * @var Revision  | 
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| 133 | */  | 
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| 134 | protected $revision = null;  | 
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| 135 | /**  | 
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| 136 | * Creation date of this revision  | 
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| 137 | *  | 
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| 138 | * @var \DateTimeImmutable  | 
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| 139 | */  | 
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| 140 | protected $created = null;  | 
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| 141 | /**  | 
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| 142 | * Modification date of this revision  | 
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| 143 | *  | 
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| 144 | * @var \DateTimeImmutable  | 
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| 145 | */  | 
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| 146 | protected $modified = null;  | 
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| 147 | /**  | 
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| 148 | * Publication date of this revision  | 
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| 149 | *  | 
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| 150 | * @var \DateTimeImmutable  | 
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| 151 | */  | 
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| 152 | protected $published = null;  | 
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| 153 | /**  | 
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| 154 | * Deletion date of this revision  | 
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| 155 | *  | 
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| 156 | * @var \DateTimeImmutable  | 
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| 157 | */  | 
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| 158 | protected $deleted = null;  | 
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| 159 | /**  | 
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| 160 | * Location  | 
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| 161 | *  | 
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| 162 | * @var LocationProperties  | 
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| 163 | */  | 
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| 164 | protected $location = null;  | 
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| 165 | /**  | 
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| 166 | * Language (BCP 47 compliant)  | 
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| 167 | *  | 
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| 168 | * @var string  | 
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| 169 | * @see https://tools.ietf.org/html/bcp47  | 
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| 170 | */  | 
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| 171 | protected $language = null;  | 
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| 172 | |||
| 173 | /**  | 
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| 174 | * System properties constructor  | 
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| 175 | *  | 
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| 176 | * @param array $data Property data  | 
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| 177 | * @param ObjectInterface $object Owner object  | 
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| 178 | */  | 
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| 179 | 27 | public function __construct(array $data, ObjectInterface $object)  | 
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| 180 |     { | 
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| 181 | 27 | parent::__construct($data, $object);  | 
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| 182 | |||
| 183 | // Initialize the object ID  | 
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| 184 | 27 |         if (array_key_exists(self::PROPERTY_ID, $data)) { | 
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| 185 | 25 | $this->uid = Id::unserialize($data[self::PROPERTY_ID]);  | 
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| 186 | 25 | }  | 
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| 187 | |||
| 188 | // Initialize the object type  | 
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| 189 | 27 |         if (array_key_exists(self::PROPERTY_TYPE, $data)) { | 
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| 190 | 26 | $this->type = Type::unserialize($data[self::PROPERTY_TYPE]);  | 
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| 191 | 25 | }  | 
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| 192 | |||
| 193 | // Initialize the object revision  | 
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| 194 | 26 |         if (array_key_exists(self::PROPERTY_REVISION, $data)) { | 
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| 195 | 25 | $this->revision = Revision::unserialize($data[self::PROPERTY_REVISION]);  | 
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| 196 | 25 | }  | 
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| 197 | |||
| 198 | // Initialize the object creation date  | 
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| 199 | 26 |         if (array_key_exists(self::PROPERTY_CREATED, $data)) { | 
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| 200 | 25 |             $this->created = new \DateTimeImmutable('@'.$data[self::PROPERTY_CREATED]); | 
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| 201 | 25 | }  | 
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| 202 | |||
| 203 | // Initialize the object modification date  | 
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| 204 | 26 |         if (array_key_exists(self::PROPERTY_MODIFIED, $data)) { | 
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| 205 | 25 |             $this->modified = new \DateTimeImmutable('@'.$data[self::PROPERTY_MODIFIED]); | 
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| 206 | 25 | }  | 
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| 207 | |||
| 208 | // Initialize the object publication date  | 
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| 209 | 26 |         if (array_key_exists(self::PROPERTY_PUBLISHED, $data)) { | 
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| 210 | 20 |             $this->published = new \DateTimeImmutable('@'.$data[self::PROPERTY_PUBLISHED]); | 
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| 211 | 20 | }  | 
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| 212 | |||
| 213 | // Initialize the object deletion date  | 
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| 214 | 26 |         if (array_key_exists(self::PROPERTY_DELETED, $data)) { | 
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| 215 |             $this->deleted = new \DateTimeImmutable('@'.$data[self::PROPERTY_DELETED]); | 
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| 216 | }  | 
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| 217 | |||
| 218 | // Initialize the object language  | 
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| 219 | 26 |         if (array_key_exists(self::PROPERTY_LANGUAGE, $data)) { | 
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| 220 | 25 | $this->language = trim($data[self::PROPERTY_LANGUAGE]);  | 
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| 221 | 25 | }  | 
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| 222 | |||
| 223 | // Initialize the location  | 
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| 224 | 26 | $this->location = Kernel::create(  | 
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| 225 | 26 | LocationProperties::class,  | 
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| 226 | 26 | [empty($data[self::PROPERTY_LOCATION]) ? [] : $data[self::PROPERTY_LOCATION], $this->object]  | 
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| 227 | 26 | );  | 
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| 228 | |||
| 229 | // Test if all mandatory properties are set  | 
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| 230 | 26 | if (!($this->uid instanceof Id)  | 
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| 231 | 26 | || !($this->type instanceof Type)  | 
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| 232 | 25 | || !($this->revision instanceof Revision)  | 
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| 233 | 25 | || !($this->created instanceof \DateTimeImmutable)  | 
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| 234 | 25 | || !($this->modified instanceof \DateTimeImmutable)  | 
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| 235 | 25 | || !strlen($this->language)  | 
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| 236 | 26 |         ) { | 
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| 237 | 1 | throw new InvalidArgumentException(  | 
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| 238 | 1 | 'Invalid system properties',  | 
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| 239 | InvalidArgumentException::INVALID_SYSTEM_PROPERTIES  | 
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| 240 | 1 | );  | 
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| 241 | }  | 
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| 242 | 25 | }  | 
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| 243 | |||
| 244 | /**  | 
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| 245 | * Return the object ID  | 
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| 246 | *  | 
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| 247 | * @return Id Object ID  | 
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| 248 | */  | 
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| 249 | 5 | public function getId()  | 
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| 253 | |||
| 254 | /**  | 
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| 255 | * Return the object type  | 
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| 256 | *  | 
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| 257 | * @return Type Object type  | 
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| 258 | */  | 
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| 259 | 1 | public function getType()  | 
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| 263 | |||
| 264 | /**  | 
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| 265 | * Return the object revision  | 
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| 266 | *  | 
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| 267 | * @return Revision Object revision  | 
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| 268 | */  | 
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| 269 | 24 | public function getRevision()  | 
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| 273 | |||
| 274 | /**  | 
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| 275 | * Return the object draft mode  | 
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| 276 | *  | 
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| 277 | * @return boolean Object draft mode  | 
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| 278 | */  | 
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| 279 | 5 | public function isDraft()  | 
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| 283 | |||
| 284 | /**  | 
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| 285 | * Return the object publication state  | 
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| 286 | *  | 
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| 287 | * @return boolean Object is published  | 
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| 288 | */  | 
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| 289 | public function isPublished()  | 
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| 293 | |||
| 294 | /**  | 
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| 295 | * Return the object deletion state  | 
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| 296 | *  | 
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| 297 | * @return boolean Object is deleted  | 
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| 298 | */  | 
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| 299 | public function isDeleted()  | 
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| 303 | |||
| 304 | /**  | 
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| 305 | * Return the creation date & time of this revision  | 
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| 306 | *  | 
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| 307 | * @return \DateTimeImmutable Creation date & time  | 
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| 308 | */  | 
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| 309 | 1 | public function getCreated()  | 
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| 313 | |||
| 314 | /**  | 
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| 315 | * Return the modification date & time of this revision  | 
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| 316 | *  | 
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| 317 | * @return \DateTimeImmutable Modification date & time  | 
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| 318 | */  | 
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| 319 | 1 | public function getModified()  | 
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| 323 | |||
| 324 | /**  | 
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| 325 | * Return the publication date & time of this revision  | 
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| 326 | *  | 
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| 327 | * @return \DateTimeImmutable|null Publication date & time  | 
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| 328 | */  | 
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| 329 | 1 | public function getPublished()  | 
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| 333 | |||
| 334 | /**  | 
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| 335 | * Return the deletion date & time of this revision  | 
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| 336 | *  | 
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| 337 | * @return \DateTimeImmutable|null Deletion date & time  | 
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| 338 | */  | 
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| 339 | 1 | public function getDeleted()  | 
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| 343 | |||
| 344 | /**  | 
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| 345 | * Return the object language  | 
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| 346 | *  | 
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| 347 | * @return string  | 
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| 348 | */  | 
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| 349 | 1 | public function getLanguage()  | 
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| 353 | |||
| 354 | /**  | 
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| 355 | * Return the latitude  | 
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| 356 | *  | 
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| 357 | * @return float Latitude  | 
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| 358 | */  | 
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| 359 | 1 | public function getLatitude()  | 
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| 363 | |||
| 364 | /**  | 
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| 365 | * Set the latitude  | 
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| 366 | *  | 
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| 367 | * @param float $latitude Latitude  | 
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| 368 | * @return SystemProperties Self reference  | 
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| 369 | */  | 
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| 370 | 1 | public function setLatitude($latitude)  | 
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| 377 | |||
| 378 | /**  | 
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| 379 | * Return the longitude  | 
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| 380 | *  | 
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| 381 | * @return float Longitude  | 
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| 382 | */  | 
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| 383 | 1 | public function getLongitude()  | 
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| 387 | |||
| 388 | /**  | 
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| 389 | * Set the longitude  | 
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| 390 | *  | 
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| 391 | * @param float $longitude Longitude  | 
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| 392 | * @return SystemProperties Self reference  | 
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| 393 | */  | 
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| 394 | 1 | public function setLongitude($longitude)  | 
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| 401 | |||
| 402 | /**  | 
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| 403 | * Return the elevation  | 
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| 404 | *  | 
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| 405 | * @return float Elevation  | 
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| 406 | */  | 
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| 407 | 1 | public function getElevation()  | 
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| 411 | |||
| 412 | /**  | 
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| 413 | * Set the elevation  | 
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| 414 | *  | 
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| 415 | * @param float $elevation  | 
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| 416 | * @return SystemProperties Self reference  | 
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| 417 | */  | 
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| 418 | 1 | public function setElevation($elevation)  | 
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| 425 | |||
| 426 | /**  | 
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| 427 | * Derive draft system properties  | 
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| 428 | *  | 
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| 429 | * @param Revision $draftRevision Draft revision  | 
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| 430 | * @return SystemProperties Draft system properties  | 
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| 431 | */  | 
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| 432 | 4 | public function createDraft(Revision $draftRevision)  | 
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| 447 | |||
| 448 | /**  | 
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| 449 | * Indicate that the object got published  | 
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| 450 | *  | 
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| 451 | * @return SystemProperties System properties  | 
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| 452 | * @throws RuntimeException If the object is already published  | 
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| 453 | */  | 
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| 454 | 2 | public function publish()  | 
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| 468 | |||
| 469 | /**  | 
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| 470 | * Update the object's modification timestamp  | 
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| 471 | *  | 
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| 472 | * @return SystemProperties System properties  | 
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| 473 | */  | 
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| 474 | 7 | public function touch()  | 
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| 480 | |||
| 481 | /**  | 
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| 482 | * Set the object's deletion timestamp  | 
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| 483 | *  | 
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| 484 | * @return SystemProperties System properties  | 
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| 485 | */  | 
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| 486 | public function delete()  | 
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| 492 | |||
| 493 | /**  | 
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| 494 | * Unset the object's deletion timestamp  | 
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| 495 | *  | 
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| 496 | * @return SystemProperties System properties  | 
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| 497 | */  | 
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| 498 | public function undelete()  | 
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| 504 | |||
| 505 | /**  | 
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| 506 | * Return the property values as array  | 
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| 507 | *  | 
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| 508 | * @return array Property values  | 
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| 509 | */  | 
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| 510 | 5 | public function toArray()  | 
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| 525 | }  | 
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| 526 |