Duplicate code is one of the most pungent code smells. A rule that is often used is to re-structure code once it is duplicated in three or more places.
Common duplication problems, and corresponding solutions are:
Complex classes like ReportTcpdf 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 ReportTcpdf, and based on these observations, apply Extract Interface, too.
1 | <?php |
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25 | class ReportTcpdf extends TCPDF { |
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26 | /** @var ReportBaseElement[] Array of elements in the header */ |
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27 | public $headerElements = []; |
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28 | |||
29 | /** @var ReportBaseElement[] Array of elements in the page header */ |
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30 | public $pageHeaderElements = []; |
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31 | |||
32 | /** @var ReportBaseElement[] Array of elements in the footer */ |
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33 | public $footerElements = []; |
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34 | |||
35 | /** @var ReportBaseElement[] Array of elements in the body */ |
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36 | public $bodyElements = []; |
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37 | |||
38 | /** @var ReportBaseFootnote[] Array of elements in the footer notes */ |
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39 | public $printedfootnotes = []; |
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40 | |||
41 | /** @var string Currently used style name */ |
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42 | public $currentStyle; |
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43 | |||
44 | /** @var int The last cell height */ |
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45 | public $lastCellHeight = 0; |
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46 | |||
47 | /** @var int The largest font size within a TextBox to calculate the height */ |
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48 | public $largestFontHeight = 0; |
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49 | |||
50 | /** @var int The last pictures page number */ |
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51 | public $lastpicpage = 0; |
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52 | |||
53 | /** @var ReportBase The current report. */ |
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54 | public $wt_report; |
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55 | |||
56 | /** |
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57 | * PDF Header -PDF |
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58 | */ |
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59 | public function header() { |
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79 | |||
80 | /** |
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81 | * PDF Body -PDF |
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82 | */ |
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83 | public function body() { |
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97 | |||
98 | /** |
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99 | * PDF Footnotes -PDF |
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100 | */ |
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101 | public function footnotes() { |
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112 | |||
113 | /** |
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114 | * PDF Footer -PDF |
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115 | */ |
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116 | View Code Duplication | public function footer() { |
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127 | |||
128 | /** |
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129 | * Add an element to the Header -PDF |
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130 | * |
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131 | * @param object|string $element |
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132 | * |
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133 | * @return int The number of the Header elements |
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134 | */ |
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135 | public function addHeader($element) { |
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140 | |||
141 | /** |
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142 | * Add an element to the Page Header -PDF |
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143 | * |
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144 | * @param object|string $element |
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145 | * |
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146 | * @return int The number of the Page Header elements |
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147 | */ |
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148 | public function addPageHeader($element) { |
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153 | |||
154 | /** |
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155 | * Add an element to the Body -PDF |
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156 | * |
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157 | * @param object|string $element |
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158 | * |
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159 | * @return int The number of the Body elements |
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160 | */ |
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161 | public function addBody($element) { |
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166 | |||
167 | /** |
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168 | * Add an element to the Footer -PDF |
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169 | * |
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170 | * @param object|string $element |
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171 | * |
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172 | * @return int The number of the Footer elements |
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173 | */ |
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174 | public function addFooter($element) { |
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179 | |||
180 | /** |
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181 | * Remove the header. |
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182 | * |
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183 | * @param $index |
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184 | */ |
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185 | public function removeHeader($index) { |
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188 | |||
189 | /** |
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190 | * Remove the page header. |
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191 | * |
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192 | * @param $index |
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193 | */ |
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194 | public function removePageHeader($index) { |
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197 | |||
198 | /** |
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199 | * Remove the body. |
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200 | * |
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201 | * @param $index |
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202 | */ |
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203 | public function removeBody($index) { |
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206 | |||
207 | /** |
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208 | * Remove the footer. |
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209 | * |
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210 | * @param $index |
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211 | */ |
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212 | public function removeFooter($index) { |
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215 | |||
216 | /** |
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217 | * Clear the Header -PDF |
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218 | */ |
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219 | public function clearHeader() { |
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223 | |||
224 | /** |
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225 | * Clear the Page Header -PDF |
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226 | */ |
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227 | public function clearPageHeader() { |
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231 | |||
232 | /** |
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233 | * Set the report. |
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234 | * |
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235 | * @param $r |
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236 | */ |
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237 | public function setReport($r) { |
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240 | |||
241 | /** |
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242 | * Get the currently used style name -PDF |
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243 | * |
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244 | * @return string |
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245 | */ |
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246 | public function getCurrentStyle() { |
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249 | |||
250 | /** |
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251 | * Setup a style for usage -PDF |
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252 | * |
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253 | * @param string $s Style name |
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254 | */ |
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255 | public function setCurrentStyle($s) { |
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260 | |||
261 | /** |
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262 | * Get the style -PDF |
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263 | * |
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264 | * @param string $s Style name |
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265 | * |
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266 | * @return array |
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267 | */ |
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268 | public function getStyle($s) { |
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276 | |||
277 | /** |
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278 | * Add margin when static horizontal position is used -PDF |
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279 | * RTL supported |
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280 | * |
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281 | * @param float $x Static position |
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282 | * |
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283 | * @return float |
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284 | */ |
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285 | public function addMarginX($x) { |
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296 | |||
297 | /** |
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298 | * Get the maximum line width to draw from the curren position -PDF |
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299 | * RTL supported |
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300 | * |
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301 | * @return float |
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302 | */ |
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303 | public function getMaxLineWidth() { |
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311 | |||
312 | /** |
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313 | * Get the height of the footnote. |
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314 | * |
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315 | * @return int |
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316 | */ |
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317 | public function getFootnotesHeight() { |
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325 | |||
326 | /** |
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327 | * Returns the the current font size height -PDF |
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328 | * |
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329 | * @return int |
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330 | */ |
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331 | View Code Duplication | public function getCurrentStyleHeight() { |
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339 | |||
340 | /** |
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341 | * Checks the Footnote and numbers them |
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342 | * |
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343 | * @param object $footnote |
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344 | * |
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345 | * @return bool false if not numbered befor | object if already numbered |
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346 | */ |
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347 | View Code Duplication | public function checkFootnote($footnote) { |
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368 | |||
369 | /** |
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370 | * Used this function instead of AddPage() |
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371 | * This function will make sure that images will not be overwritten |
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372 | */ |
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373 | public function newPage() { |
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379 | |||
380 | /** |
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381 | * Add a page if needed -PDF |
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382 | * |
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383 | * @param int $height Cell height |
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384 | * |
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385 | * @return bool true in case of page break, false otherwise |
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386 | */ |
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387 | public function checkPageBreakPDF($height) { |
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390 | |||
391 | /** |
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392 | * Returns the remaining width between the current position and margins -PDF |
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393 | * |
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394 | * @return float Remaining width |
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395 | */ |
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396 | public function getRemainingWidthPDF() { |
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399 | } |
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400 |
Let’s take a look at an example:
In the above example, the authenticate() method works fine as long as you just pass instances of MyUser. However, if you now also want to pass a different sub-classes of User which does not have a getDisplayName() method, the code will break.
Available Fixes
Change the type-hint for the parameter:
Add an additional type-check:
Add the method to the parent class: