Complex classes like StateMachine 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.
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 StateMachine, and based on these observations, apply Extract Interface, too.
1 | <?php |
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22 | class StateMachine implements StateMachineInterface |
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23 | { |
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24 | /** |
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25 | * The stateful object. |
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26 | * |
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27 | * @var object |
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28 | */ |
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29 | protected $object; |
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30 | |||
31 | /** |
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32 | * The available states. |
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33 | * |
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34 | * @var array |
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35 | */ |
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36 | protected $states = array(); |
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37 | |||
38 | /** |
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39 | * The available transitions. |
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40 | * |
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41 | * @var array |
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42 | */ |
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43 | protected $transitions = array(); |
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44 | |||
45 | /** |
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46 | * The current state. |
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47 | * |
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48 | * @var StateInterface |
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49 | */ |
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50 | protected $currentState; |
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51 | |||
52 | /** |
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53 | * @var StateMachineDispatcher |
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54 | */ |
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55 | protected $dispatcher; |
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56 | |||
57 | /** |
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58 | * @var StateAccessorInterface |
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59 | */ |
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60 | protected $stateAccessor; |
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61 | |||
62 | /** |
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63 | * @var string |
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64 | */ |
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65 | protected $graph; |
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66 | |||
67 | /** |
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68 | * @param object $object |
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69 | * @param StateMachineDispatcher $dispatcher |
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70 | * @param StateAccessorInterface $stateAccessor |
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71 | */ |
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72 | 185 | public function __construct( |
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73 | $object = null, |
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74 | StateMachineDispatcher $dispatcher = null, |
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75 | StateAccessorInterface $stateAccessor = null |
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76 | ) { |
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77 | 185 | $this->object = $object; |
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78 | 185 | $this->dispatcher = $dispatcher ?: new StateMachineDispatcher(); |
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79 | 185 | $this->stateAccessor = $stateAccessor ?: new PropertyPathStateAccessor(); |
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80 | 185 | } |
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81 | |||
82 | /** |
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83 | * {@inheritdoc} |
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84 | */ |
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85 | 160 | public function initialize() |
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86 | { |
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87 | 160 | if (null === $this->object) { |
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88 | throw new Exception\ObjectException('No object bound to the State Machine'); |
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89 | } |
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90 | |||
91 | try { |
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92 | 160 | $initialState = $this->stateAccessor->getState($this->object); |
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93 | } catch (Exception\NoSuchPropertyException $e) { |
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94 | throw new Exception\ObjectException(sprintf( |
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95 | 'StateMachine can\'t be initialized because the defined property_path of object "%s" does not exist.', |
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96 | $this->getObject() ? get_class($this->getObject()) : null |
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97 | ), $e->getCode(), $e); |
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98 | } |
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99 | |||
100 | 160 | if (null === $initialState) { |
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101 | 20 | $initialState = $this->findInitialState(); |
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102 | 20 | $this->stateAccessor->setState($this->object, $initialState); |
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103 | |||
104 | 20 | $this->dispatcher->dispatch(FiniteEvents::SET_INITIAL_STATE, new StateMachineEvent($this)); |
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105 | } |
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106 | |||
107 | 158 | $this->currentState = $this->getState($initialState); |
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108 | |||
109 | 158 | $this->dispatcher->dispatch(FiniteEvents::INITIALIZE, new StateMachineEvent($this)); |
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110 | 144 | } |
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111 | |||
112 | /** |
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113 | * {@inheritdoc} |
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114 | * |
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115 | * @throws Exception\StateException |
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116 | */ |
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117 | 19 | public function apply($transitionName, array $parameters = array()) |
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118 | { |
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119 | 19 | $transition = $this->getTransition($transitionName); |
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120 | 19 | $event = new TransitionEvent($this->getCurrentState(), $transition, $this, $parameters); |
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121 | 19 | if (!$this->can($transition, $parameters)) { |
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122 | 5 | throw new Exception\StateException(sprintf( |
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123 | 5 | 'The "%s" transition can not be applied to the "%s" state of object "%s" with graph "%s".', |
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124 | 5 | $transition->getName(), |
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125 | 5 | $this->currentState->getName(), |
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126 | 5 | $this->getObject() ? get_class($this->getObject()) : null, |
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127 | 5 | $this->getGraph() |
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128 | )); |
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129 | } |
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130 | |||
131 | 19 | $this->dispatchTransitionEvent($transition, $event, FiniteEvents::PRE_TRANSITION); |
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132 | |||
133 | 19 | $returnValue = $transition->process($this); |
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134 | 19 | $this->stateAccessor->setState($this->object, $transition->getState()); |
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135 | 19 | $this->currentState = $this->getState($transition->getState()); |
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136 | |||
137 | 19 | $this->dispatchTransitionEvent($transition, $event, FiniteEvents::POST_TRANSITION); |
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138 | |||
139 | 19 | return $returnValue; |
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140 | } |
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141 | |||
142 | /** |
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143 | * {@inheritdoc} |
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144 | */ |
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145 | 52 | public function can($transition, array $parameters = array()) |
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162 | |||
163 | /** |
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164 | * {@inheritdoc} |
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165 | */ |
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166 | 185 | public function addState($state) |
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174 | |||
175 | /** |
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176 | * {@inheritdoc} |
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177 | */ |
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178 | 180 | public function addTransition($transition, $initialState = null, $finalState = null) |
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179 | { |
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180 | 180 | if ((null === $initialState || null === $finalState) && !$transition instanceof TransitionInterface) { |
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181 | throw new \InvalidArgumentException( |
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182 | 'You must provide a TransitionInterface instance or the $transition, '. |
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183 | '$initialState and $finalState parameters' |
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184 | ); |
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185 | } |
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186 | // If transition isn't a TransitionInterface instance, we create one from the states date |
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187 | 180 | if (!$transition instanceof TransitionInterface) { |
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188 | try { |
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189 | 155 | $transition = $this->getTransition($transition); |
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190 | 155 | } catch (Exception\TransitionException $e) { |
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191 | 155 | $transition = new Transition($transition, $initialState, $finalState); |
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192 | } |
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193 | } |
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194 | |||
195 | 180 | $this->transitions[$transition->getName()] = $transition; |
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196 | |||
197 | // We add missings states to the State Machine |
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198 | try { |
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199 | 180 | $this->getState($transition->getState()); |
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200 | 90 | } catch (Exception\StateException $e) { |
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201 | 90 | $this->addState($transition->getState()); |
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202 | } |
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203 | 180 | foreach ($transition->getInitialStates() as $state) { |
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204 | try { |
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205 | 180 | $this->getState($state); |
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206 | 35 | } catch (Exception\StateException $e) { |
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207 | 35 | $this->addState($state); |
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208 | } |
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209 | 180 | $state = $this->getState($state); |
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210 | 180 | if ($state instanceof State) { |
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211 | 180 | $state->addTransition($transition); |
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212 | } |
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213 | } |
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214 | 180 | } |
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215 | |||
216 | /** |
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217 | * {@inheritdoc} |
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218 | */ |
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219 | 159 | public function getTransition($name) |
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220 | { |
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221 | 159 | if (!isset($this->transitions[$name])) { |
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222 | 155 | throw new Exception\TransitionException(sprintf( |
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223 | 155 | 'Unable to find a transition called "%s" on object "%s" with graph "%s".', |
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224 | 155 | $name, |
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225 | 155 | $this->getObject() ? get_class($this->getObject()) : null, |
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226 | 155 | $this->getGraph() |
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227 | )); |
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228 | } |
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229 | |||
230 | 51 | return $this->transitions[$name]; |
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231 | } |
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232 | |||
233 | /** |
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234 | * {@inheritdoc} |
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235 | */ |
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236 | 185 | public function getState($name) |
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237 | { |
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238 | 185 | $name = (string) $name; |
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239 | |||
240 | 185 | if (!isset($this->states[$name])) { |
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241 | 95 | throw new Exception\StateException(sprintf( |
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242 | 95 | 'Unable to find a state called "%s" on object "%s" with graph "%s".', |
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243 | 95 | $name, |
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244 | 95 | $this->getObject() ? get_class($this->getObject()) : null, |
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245 | 95 | $this->getGraph() |
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246 | )); |
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247 | } |
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248 | |||
249 | 185 | return $this->states[$name]; |
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250 | } |
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251 | |||
252 | /** |
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253 | * {@inheritdoc} |
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254 | */ |
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255 | 5 | public function getTransitions() |
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259 | |||
260 | /** |
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261 | * {@inheritdoc} |
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262 | */ |
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263 | 5 | public function getStates() |
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267 | |||
268 | /** |
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269 | * {@inheritdoc} |
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270 | */ |
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271 | 150 | public function setObject($object) |
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272 | { |
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273 | 150 | $this->object = $object; |
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274 | 150 | } |
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275 | |||
276 | /** |
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277 | * {@inheritdoc} |
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278 | */ |
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279 | 174 | public function getObject() |
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283 | |||
284 | /** |
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285 | * {@inheritdoc} |
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286 | */ |
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287 | 100 | public function getCurrentState() |
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291 | |||
292 | /** |
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293 | * Find and return the Initial state if exists. |
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294 | * |
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295 | * @return string |
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296 | * |
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297 | * @throws Exception\StateException |
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298 | */ |
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299 | 20 | protected function findInitialState() |
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300 | { |
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301 | 20 | foreach ($this->states as $state) { |
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302 | 20 | if (State::TYPE_INITIAL === $state->getType()) { |
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303 | 20 | return $state->getName(); |
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304 | } |
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305 | } |
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306 | |||
307 | throw new Exception\StateException(sprintf( |
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308 | 'No initial state found on object "%s" with graph "%s".', |
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309 | $this->getObject() ? get_class($this->getObject()) : null, |
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310 | $this->getGraph() |
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311 | )); |
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312 | } |
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313 | |||
314 | /** |
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315 | * @param StateMachineDispatcher $dispatcher |
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316 | */ |
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317 | public function setDispatcher(StateMachineDispatcher $dispatcher) |
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318 | { |
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319 | $this->dispatcher = $dispatcher; |
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320 | } |
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321 | |||
322 | /** |
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323 | * @return StateMachineDispatcher |
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324 | */ |
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325 | 5 | public function getDispatcher() |
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329 | |||
330 | /** |
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331 | * @param StateAccessorInterface $stateAccessor |
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332 | */ |
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333 | 5 | public function setStateAccessor(StateAccessorInterface $stateAccessor) |
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334 | { |
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335 | 5 | $this->stateAccessor = $stateAccessor; |
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336 | 5 | } |
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337 | |||
338 | /** |
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339 | * {@inheritdoc} |
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340 | */ |
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341 | 15 | public function hasStateAccessor() |
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345 | |||
346 | /** |
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347 | * {@inheritdoc} |
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348 | */ |
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349 | 20 | public function setGraph($graph) |
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350 | { |
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351 | 20 | $this->graph = $graph; |
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352 | 20 | } |
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353 | |||
354 | /** |
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355 | * {@inheritdoc} |
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356 | */ |
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357 | 174 | public function getGraph() |
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361 | |||
362 | /** |
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363 | * {@inheritDoc} |
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364 | */ |
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365 | 10 | public function findStateWithProperty($property, $value = null) |
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366 | { |
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367 | 10 | return array_keys( |
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368 | 10 | array_map( |
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369 | 6 | function (State $state) { |
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370 | 10 | return $state->getName(); |
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371 | 10 | }, |
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372 | 10 | array_filter( |
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373 | 10 | $this->states, |
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374 | 10 | function (State $state) use ($property, $value) { |
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375 | 10 | if (!$state->has($property)) { |
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376 | 10 | return false; |
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377 | } |
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378 | |||
379 | 10 | if (null !== $value && $state->get($property) !== $value) { |
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380 | 5 | return false; |
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381 | } |
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382 | |||
383 | 10 | return true; |
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384 | 10 | } |
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385 | ) |
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386 | ) |
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387 | ); |
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388 | } |
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389 | |||
390 | /** |
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391 | * Dispatches event for the transition |
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392 | * |
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393 | * @param TransitionInterface $transition |
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394 | * @param TransitionEvent $event |
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395 | * @param type $transitionState |
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396 | */ |
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397 | 47 | private function dispatchTransitionEvent(TransitionInterface $transition, TransitionEvent $event, $transitionState) |
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405 | } |
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406 |
It seems like the type of the argument is not accepted by the function/method which you are calling.
In some cases, in particular if PHP’s automatic type-juggling kicks in this might be fine. In other cases, however this might be a bug.
We suggest to add an explicit type cast like in the following example: