Complex classes like FieldResolver 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 FieldResolver, and based on these observations, apply Extract Interface, too.
1 | <?php |
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37 | class FieldResolver extends ResolverBase |
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38 | { |
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39 | |||
40 | /** |
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41 | * @var mixed $model |
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42 | */ |
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43 | protected $model; |
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44 | |||
45 | /** |
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46 | * @var array $fields . |
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47 | */ |
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48 | protected $fields; |
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49 | |||
50 | |||
51 | /** |
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52 | * FieldResolver constructor. |
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53 | * |
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54 | * @param mixed $model The model instance. |
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55 | * @param array $fields The fields registered for the type. |
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56 | */ |
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57 | public function __construct($model, array $fields) |
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62 | |||
63 | |||
64 | /** |
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65 | * @param mixed $source The source that's passed down the GraphQL queries |
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66 | * @param array $args The inputArgs on the field |
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67 | * @param AppContext $context The AppContext passed down the GraphQL tree |
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68 | * @param ResolveInfo $info The ResolveInfo passed down the GraphQL tree |
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69 | * @return string |
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70 | * @throws EE_Error |
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71 | * @throws Exception |
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72 | * @throws InvalidArgumentException |
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73 | * @throws InvalidDataTypeException |
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74 | * @throws InvalidInterfaceException |
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75 | * @throws ReflectionException |
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76 | * @throws UserError |
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77 | * @throws UnexpectedEntityException |
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78 | * @since $VID:$ |
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79 | */ |
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80 | public function resolve($source, array $args, AppContext $context, ResolveInfo $info) |
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81 | { |
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82 | $fieldName = $info->fieldName; |
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83 | $field = isset($this->fields[ $fieldName ]) ? $this->fields[ $fieldName ] : null; |
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84 | // Field should exist in teh registered fields |
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85 | if ($field instanceof GraphQLField) { |
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86 | // check if the field should be resolved. |
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87 | if (! $field->shouldResolve()) { |
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88 | return null; |
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89 | } |
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90 | // Give priority to the internal resolver. |
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91 | if ($field->hasInternalResolver()) { |
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92 | return $field->resolve($source, $args, $context, $info); |
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93 | } |
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94 | if (! ($source instanceof EE_Base_Class)) { |
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95 | return null; |
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96 | } |
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97 | // Check if the field has a key mapped to model. |
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98 | if (! empty($field->key())) { |
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99 | $value = $source->{$field->key()}(); |
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100 | return $field->mayBeFormatValue($value, $source); |
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101 | } |
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102 | switch ($fieldName) { |
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103 | case 'id': // the global ID |
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104 | return $this->resolveId($source); |
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105 | case 'cacheId': |
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106 | return $this->resolveCacheId($source); |
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107 | case 'parent': |
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108 | return $this->resolveParent($source); |
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109 | case 'event': |
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110 | return $this->resolveEvent($source, $args, $context); |
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111 | case 'wpUser': |
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112 | case 'manager': |
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113 | return $this->resolveWpUser($source, $args, $context); |
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114 | case 'userId': |
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115 | return $this->resolveUserId($source, $args, $context); |
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116 | case 'state': // Venue |
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117 | return $this->resolveState($source); |
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118 | case 'country': // State, Venue |
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119 | return $this->resolveCountry($source); |
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120 | } |
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121 | } |
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122 | return null; |
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123 | } |
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124 | |||
125 | |||
126 | /** |
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127 | * Resolve the global ID |
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128 | * |
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129 | * @param mixed $source |
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130 | * @return string|null |
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131 | * @throws Exception |
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132 | * @since $VID:$ |
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133 | */ |
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134 | public function resolveId($source) |
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140 | |||
141 | |||
142 | /** |
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143 | * Resolve the cache ID |
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144 | * |
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145 | * @param mixed $source |
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146 | * @return string |
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147 | * @since $VID:$ |
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148 | */ |
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149 | public function resolveCacheId($source) |
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158 | |||
159 | |||
160 | /** |
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161 | * @param mixed $source |
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162 | * @param $args |
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163 | * @param $context |
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164 | * @return Deferred|null |
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165 | * @throws Exception |
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166 | * @since $VID:$ |
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167 | */ |
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168 | public function resolveWpUser($source, $args, $context) |
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175 | |||
176 | |||
177 | /** |
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178 | * @param mixed $source |
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179 | * @param $args |
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180 | * @param $context |
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181 | * @return Deferred|null |
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182 | * @throws Exception |
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183 | * @since $VID:$ |
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184 | */ |
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185 | public function resolveUserId($source, $args, $context) |
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190 | |||
191 | |||
192 | /** |
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193 | * @param mixed $source |
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194 | * @return EE_Base_Class|null |
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195 | * @throws EE_Error |
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196 | * @throws InvalidArgumentException |
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197 | * @throws InvalidDataTypeException |
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198 | * @throws InvalidInterfaceException |
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199 | * @throws ReflectionException |
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200 | * @since $VID:$ |
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201 | */ |
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202 | public function resolveParent($source) |
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206 | |||
207 | |||
208 | /** |
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209 | * @param mixed $source |
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210 | * @param $args |
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211 | * @param $context |
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212 | * @return Deferred|null |
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213 | * @throws EE_Error |
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214 | * @throws InvalidArgumentException |
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215 | * @throws InvalidDataTypeException |
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216 | * @throws InvalidInterfaceException |
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217 | * @throws ReflectionException |
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218 | * @throws UserError |
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219 | * @throws UnexpectedEntityException |
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220 | * @since $VID:$ |
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221 | */ |
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222 | public function resolveEvent($source, $args, $context) |
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240 | |||
241 | |||
242 | /** |
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243 | * @param mixed $source The source instance. |
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244 | * @return EE_Base_Class|null |
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245 | * @throws EE_Error |
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246 | * @throws InvalidArgumentException |
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247 | * @throws InvalidDataTypeException |
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248 | * @throws InvalidInterfaceException |
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249 | * @since $VID:$ |
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250 | */ |
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251 | public function resolveState($source) |
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266 | |||
267 | |||
268 | /** |
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269 | * @param mixed $source The source instance. |
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270 | * @return EE_Base_Class|null |
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271 | * @throws EE_Error |
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272 | * @throws InvalidArgumentException |
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273 | * @throws InvalidDataTypeException |
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274 | * @throws InvalidInterfaceException |
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275 | * @since $VID:$ |
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276 | */ |
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277 | public function resolveCountry($source) |
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296 | } |
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297 |
It seems like the method you are trying to call exists only in some of the possible types.
Let’s take a look at an example:
Available Fixes
Add an additional type-check:
Only allow a single type to be passed if the variable comes from a parameter: