docs(10_Wiki): Topic_Business/General/Graphic/Programming을 Topics/ 하위로 이동

최상위 10_Wiki/Topic_*였던 4개 카테고리 폴더를 10_Wiki/Topics/Topic_* 로 재배치. 콘텐츠 변경 없음(순수 폴더 이동) — Topics/ 하위 나머지 폴더는 이미 지난 커밋에서 전부 정리된 상태(잔존 항목은 에이전트 운영 상태 및 사용자가 보존을 요청한 업데이트0615/무제 3.canvas 뿐).
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+---
+id: php-exception
+title: "PHP Exception"
+category: "Programming_Language"
+status: "draft"
+verification_status: "conceptual"
+canonical_id: ""
+aliases: ["custom exception class", "re-throwing", "set_exception_handler", "PHP 예외 처리 심화"]
+duplicate_of: ""
+source_trust_level: "B"
+confidence_score: 0.9
+created_at: 2026-07-04
+updated_at: 2026-07-04
+review_reason: ""
+merge_history: []
+tags: ["php", "programming", "w3schools", "exceptions", "oop"]
+raw_sources: ["https://www.w3schools.com/php/php_exception.asp"]
+applied_in: []
+github_commit: ""
+---
+
+# [[PHP Exception]]
+
+## 🎯 한 줄 통찰 (One-line insight)
+Re-throwing an exception requires nesting a `try` block INSIDE another `try` block — the inner try catches the raw system exception, then throws a new user-friendly `customException` in its own catch block, which the OUTER catch finally handles; this two-layer structure is how PHP lets you translate an internal error into a message safe to show end users. [S1]
+
+## 🧠 핵심 개념 (Core concepts)
+- **Custom exception class** — must `extends Exception`; inherits `getLine()`, `getFile()`, `getMessage()`, and can add custom methods. [S1]
+- **Multiple exceptions** — a try block can have MULTIPLE catch blocks for different exception classes; PHP matches the first applicable one. [S1]
+- **Re-throwing** — nesting a try/catch inside another try, so a caught exception can be replaced with a different (often more user-friendly) one before reaching the outer catch. [S1]
+- **`set_exception_handler($functionName)`** — installs a top-level handler that catches ANY exception with no matching catch block anywhere. [S1]
+- **Core rule** — "If you throw something, you have to catch it" — every throw needs at least one corresponding catch (or a top-level handler as the ultimate fallback). [S1]
+
+## 📖 세부 내용 (Details)
+- Custom exception class: `class customException extends Exception { public function errorMessage() { return 'Error on line '.$this->getLine().' in '.$this->getFile().': '.$this->getMessage().' is not a valid E-Mail address'; } }`. [S1]
+- Using it: `try { if(filter_var($email, FILTER_VALIDATE_EMAIL) === FALSE) { throw new customException($email); } } catch (customException $e) { echo $e->errorMessage(); }`. [S1]
+- Multiple catch blocks for different conditions: `try { if(...) { throw new customException($email); } if(strpos($email, "example") !== FALSE) { throw new Exception("$email is an example e-mail"); } } catch (customException $e) { ... } catch(Exception $e) { ... }`. [S1]
+- Re-throwing pattern: `try { try { if(strpos($email, "example") !== FALSE) { throw new Exception($email); } } catch(Exception $e) { throw new customException($email); } } catch (customException $e) { echo $e->errorMessage(); }`. [S1]
+- Top-level handler: `function myException($exception) { echo "Exception: " . $exception->getMessage(); } set_exception_handler('myException'); throw new Exception('Uncaught Exception occurred');`. [S1]
+
+## ⚖️ 모순 및 업데이트 (Contradictions & updates)
+- **재발생(re-throw)의 이중 try 구조**: 원본 시스템 에러를 사용자 친화적 메시지로 바꾸려면 try 블록 안에 또 다른 try 블록을 중첩해야 한다는 구조적 필요성이 예제로 명확히 드러남. [S1]
+
+## 🛠️ 적용 사례 (Applied in summary)
+현재 발견된 실제 적용 사례가 없습니다 — 이메일 형식 오류를 커스텀 예외 클래스로 감싸 사용자 친화적 메시지를 보여주는 것이 실전 예외 설계의 대표 사례다. [S1]
+
+## 💻 코드 패턴 (Code patterns)
+Re-throwing a system exception as a user-friendly custom exception (PHP):
+```php
+class customException extends Exception {
+    public function errorMessage() {
+        return $this->getMessage() . ' is not a valid E-Mail address.';
+    }
+}
+try {
+    try {
+        if (strpos($email, "example") !== FALSE) {
+            throw new Exception($email);
+        }
+    } catch (Exception $e) {
+        throw new customException($email); // re-throw as friendlier exception
+    }
+} catch (customException $e) {
+    echo $e->errorMessage();
+}
+```
+
+## ✅ 검증 상태 및 신뢰도
+- **상태:** draft
+- **검증 단계:** conceptual
+- **출처 신뢰도:** B (W3Schools — widely used educational reference, not a primary standards body)
+- **신뢰 점수:** 0.90
+- **중복 검사 결과:** 신규 생성 (New discovery)
+
+## 🔗 지식 그래프 (Knowledge Graph)
+- **상위/루트:** [[PHP Tutorial]]
+- **관련 개념:** [[PHP Exceptions]], [[PHP Error Handling]], [[PHP OOP Inheritance]]
+- **참조 맥락:** 커스텀 예외 클래스와 상속 — OOP 섹션의 상속(Inheritance) 개념과 직접 연결됨.
+
+## 📚 출처 (Sources)
+- [S1] W3Schools — PHP Exception Handling — https://www.w3schools.com/php/php_exception.asp
+
+## 📝 변경 이력 (Change history)
+- 2026-07-04: Initial draft synthesized from the W3Schools "PHP Exception Handling" page (Astra wiki-curation, P-Reinforce v3.1 format).