spiral /
framework
| Total Complexity | 43 |
| Total Lines | 236 |
| Duplicated Lines | 0 % |
| Changes | 1 | ||
| Bugs | 0 | Features | 0 |
Complex classes like Traverser 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 Traverser, and based on these observations, apply Extract Interface, too.
| 1 | <?php |
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| 21 | final class Traverser |
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| 22 | { |
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| 23 | /** @var VisitorInterface[] */ |
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| 24 | private $visitors = []; |
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| 25 | |||
| 26 | /** @var bool */ |
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| 27 | private $stopTraversal = false; |
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| 28 | |||
| 29 | /** |
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| 30 | * @param array $visitors |
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| 31 | */ |
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| 32 | public function __construct(array $visitors = []) |
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| 36 | } |
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| 37 | } |
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| 38 | |||
| 39 | /** |
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| 40 | * Adds visitor. |
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| 41 | * |
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| 42 | * @param VisitorInterface $visitor |
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| 43 | */ |
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| 44 | public function addVisitor(VisitorInterface $visitor): void |
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| 45 | { |
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| 46 | $this->visitors[] = $visitor; |
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| 47 | } |
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| 48 | |||
| 49 | /** |
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| 50 | * @param VisitorInterface $visitor |
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| 51 | */ |
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| 52 | public function removeVisitor(VisitorInterface $visitor): void |
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| 58 | } |
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| 59 | } |
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| 60 | } |
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| 61 | |||
| 62 | /** |
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| 63 | * Traverses an array of nodes using added visitors. |
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| 64 | * |
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| 65 | * @param NodeInterface[] $nodes |
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| 66 | * @param VisitorContext $context |
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| 67 | * @return NodeInterface[] |
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| 68 | * |
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| 69 | * @throws \Throwable |
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| 70 | */ |
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| 71 | public function traverse(array $nodes, VisitorContext $context = null): array |
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| 72 | { |
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| 73 | $context = $context ?? new VisitorContext(); |
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| 74 | |||
| 75 | $ctx = clone $context; |
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| 76 | foreach ($nodes as $index => $node) { |
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| 77 | if ($this->stopTraversal) { |
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| 78 | break; |
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| 79 | } |
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| 80 | |||
| 81 | $traverseChildren = true; |
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| 82 | $breakVisitorID = null; |
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| 83 | |||
| 84 | if ($node instanceof NodeInterface) { |
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| 85 | $ctx = $context->withNode($node); |
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| 86 | } |
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| 87 | |||
| 88 | foreach ($this->visitors as $visitorID => $visitor) { |
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| 89 | $result = $visitor->enterNode($node, $ctx); |
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| 90 | |||
| 91 | switch (true) { |
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| 92 | case $result === null: |
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| 93 | break; |
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| 94 | |||
| 95 | case $result instanceof NodeInterface: |
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| 96 | $node = $result; |
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| 97 | break; |
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| 98 | |||
| 99 | case $result === VisitorInterface::DONT_TRAVERSE_CHILDREN: |
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| 100 | $traverseChildren = false; |
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| 101 | break; |
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| 102 | |||
| 103 | case $result === VisitorInterface::DONT_TRAVERSE_CURRENT_AND_CHILDREN: |
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| 104 | $traverseChildren = false; |
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| 105 | $breakVisitorID = $visitorID; |
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| 106 | break 2; |
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| 107 | |||
| 108 | case $result === VisitorInterface::STOP_TRAVERSAL: |
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| 109 | $this->stopTraversal = true; |
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| 110 | |||
| 111 | break 3; |
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| 112 | |||
| 113 | default: |
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| 114 | throw new \LogicException( |
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| 115 | 'enterNode() returned invalid value of type ' . gettype($result) |
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| 116 | ); |
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| 117 | } |
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| 118 | } |
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| 119 | |||
| 120 | // sub nodes |
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| 121 | if ($traverseChildren && $node instanceof NodeInterface) { |
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| 122 | $nodes[$index] = $this->traverseNode($node, $ctx); |
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| 123 | if ($this->stopTraversal) { |
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| 124 | break; |
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| 125 | } |
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| 126 | } |
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| 127 | |||
| 128 | foreach ($this->visitors as $visitorID => $visitor) { |
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| 129 | $result = $visitor->leaveNode($node, $ctx); |
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| 130 | |||
| 131 | switch (true) { |
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| 132 | case $result === null: |
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| 133 | break; |
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| 134 | |||
| 135 | case $result instanceof NodeInterface: |
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| 136 | $nodes[$index] = $result; |
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| 137 | break; |
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| 138 | |||
| 139 | case $result === VisitorInterface::REMOVE_NODE: |
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| 140 | unset($nodes[$index]); |
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| 141 | break; |
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| 142 | |||
| 143 | case $result === VisitorInterface::STOP_TRAVERSAL: |
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| 144 | $this->stopTraversal = true; |
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| 145 | break 3; |
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| 146 | |||
| 147 | default: |
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| 148 | throw new \LogicException( |
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| 149 | 'leaveNode() returned invalid value of type ' . gettype($result) |
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| 150 | ); |
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| 151 | } |
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| 152 | |||
| 153 | if ($breakVisitorID === $visitorID) { |
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| 154 | break; |
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| 155 | } |
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| 156 | } |
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| 157 | } |
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| 158 | |||
| 159 | return array_values($nodes); |
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| 160 | } |
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| 161 | |||
| 162 | /** |
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| 163 | * Recursively traverse a node. |
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| 164 | * |
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| 165 | * @param NodeInterface $node |
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| 166 | * @param VisitorContext $context |
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| 167 | * @return NodeInterface |
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| 168 | */ |
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| 169 | private function traverseNode(NodeInterface $node, VisitorContext $context): NodeInterface |
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| 257 | } |
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| 258 | } |
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| 259 |
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