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    • Jenkins μ‹œμž‘ν•˜κΈ°
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  • 개발 방법둠
    • TDD
  • Spring
    • IoC
    • Is Spring Bean Thread-Safe?
    • Spring Singleton
    • Component Scan
    • Spring Annotation
    • 의쑴 관계 μ£Όμž…(DI)
    • Lombok ν™œμš©ν•˜κΈ°
    • Bean 생λͺ…주기와 콜백
    • Bean Scope
    • AOP(1) - AOPλž€
    • AOP(2) - Aop Proxy
    • AOP(3) - Dynamic Proxy
    • AOP(4) - AspectJ
    • POJO
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    • Transaction
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    • JPA Entity
    • Spring Data JPA
    • Spring Data Specification
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    • Cache
    • restTemplate
    • YAML 파일 μ„€μ •
    • Spring Boot
      • H2 DB μ„€μ •
      • 닀쀑 λ°μ΄ν„°λ² μ΄μŠ€ μ„€μ •
      • Mybatis μ—°λ™ν•˜κΈ°
    • Spring Batch
      • Batch μ‹œμž‘ν•΄λ³΄κΈ°
      • Batch Job Flow
      • Job
      • Step
      • Batch Scope & Job Parameter
      • JobRepository와 λ©”νƒ€ν…Œμ΄λΈ”
      • Chunk μ§€ν–₯ ν”„λ‘œκ·Έλž˜λ°
      • ItemReader
      • ItemProcessor
      • ItemWriter
      • Batch Schedular
      • Job별 Beanλ“±λ‘ν•˜κΈ°
      • Batch κ΅¬ν˜„μ‹œ λ°œμƒν•œ 였λ₯˜ 정리
      • Spring Batch Scaling
        • Multithread Jobκ΅¬ν˜„μ‹œ μ΄μŠˆμ‚¬ν•­
    • Spring test
      • Junit5
        • ν…ŒμŠ€νŠΈ 이름 ν‘œκΈ°
        • ν…ŒμŠ€νŠΈ κ·Έλ£Ή μ‚¬μ΄μ˜ 관계
        • νƒœκ·Έμ™€ 필터링
        • 동적 ν…ŒμŠ€νŠΈ
        • ν…ŒμŠ€νŠΈ LifeCycle
        • ν…ŒμŠ€νŠΈ λ©”μ„œλ“œ
        • ν…ŒμŠ€νŠΈ μˆœμ„œ
        • AssertJ
        • ν…ŒμŠ€νŠΈ 병렬 μ‹€ν–‰
        • AssertJ
        • Mock
      • Spring Boot Test DB 뢄리
      • Spring Batch Test
  • Web Application
    • Web Server & WAS
    • κ΄€λ ¨ κ°œλ… - HTTP API, HTML, CSR, SSR
    • Servlet
    • JSP
    • Cookie And Session
    • μ˜ˆμ™ΈνŽ˜μ΄μ§€
    • Java Bean
    • JDBC
    • Connection Pool
    • 파일 μ—…λ‘œλ“œ
    • Expression Language
    • JSTL
    • FrontControllerνŒ¨ν„΄ Command νŒ¨ν„΄
    • Forwarding
    • MVC
    • νšŒμ›κ°€μž…μ˜ˆμ œ
    • μ°Έκ³ 
      • κ°œλ°œν™˜κ²½μ„€μ •
  • Java+
    • SOAP/WSDL vs REST
    • WSDL을 JAVA둜 λ³€ν™˜ν•˜κΈ°
    • SOAP 톡신 OPEN API둜 κ°œλ°œν•΄λ³΄κΈ°
  • Java
    • Basic
      • λ³€μˆ˜μ™€ νƒ€μž…
      • μ—°μ‚°μž
      • 쑰건문과 반볡문
      • μ°Έμ‘° νƒ€μž…
      • 클래슀
      • 상속(Inheritance)
      • μΈν„°νŽ˜μ΄μŠ€(Interface)
      • 쀑첩 ν΄λž˜μŠ€μ™€ 쀑첩 μΈν„°νŽ˜μ΄μŠ€
      • μ˜ˆμ™Έ 처리
      • API - Object, System, Class, Math, Wrapper
      • API - String, StringBuffer, StringBuilder
      • Thread
      • Generic
      • Lambda
      • Collection - List, Set
      • Collection - Map
      • Collection - Tree
      • Collection - Stack, Queue
      • Stream
      • Reflection
      • μ •κ·œν‘œν˜„μ‹
      • GUI
      • UML
      • Serializable
    • Advanced
      • OutOfMemoryError
      • AutoValue
      • meta-annotation
        • @Retention
        • @Target
        • @Repeatable
    • Effective Java 3/E
      • ITEM 1: Static Factory Method(정적 λ©”μ†Œλ“œ)
      • ITEM 2: Builder Pattern
      • ITEM 3: Singleton
      • ITEM 4: Private Constructor
      • ITEM 5: Dependency Injection
      • ITEM 6: Avoid Unnecessary Object
      • ITEM 7: Eliminate Object Reference
      • ITEM 8: Avoid finalizer and cleaner
      • ITEM 9: try-with-resources
      • ITEM 10: The gerneral contract when overriding equlas
      • ITEM 11: Overriding hashCode
      • ITEM 12: overriding toString
      • ITEM 13: overriding clone judiciously
      • ITEM 14: Consider implementing comparable
      • ITEM 15: ν΄λž˜μŠ€μ™€ λ©€λ²„μ˜ 접근을 μ΅œμ†Œν™”ν•΄λΌ
      • ITEM 16: Use Accessor methods
      • ITEM 17: λ³€κ²½ κ°€λŠ₯성을 μ΅œμ†Œν™”ν•΄λΌ(λΆˆλ³€ 클래슀)
      • ITEM 18: 상속보단 μ»΄ν¬μ§€μ…˜μ„ μ‚¬μš©ν•΄λΌ
      • ITEM 19: 상속을 κ³ λ €ν•΄ μ„€κ³„ν•˜κ³  λ¬Έμ„œν™”ν•΄λΌ
      • ITEM 20: 좔상 ν΄λž˜μŠ€λ³΄λ‹€ μΈν„°νŽ˜μ΄μŠ€λ₯Ό μš°μ„ ν•˜λΌ
      • ITEM 21: μΈν„°νŽ˜μ΄μŠ€λŠ” κ΅¬ν˜„ν•˜λŠ” μͺ½μ„ 생각해 섀계해라.
      • ITEM 22: μΈν„°νŽ˜μ΄μŠ€λŠ” νƒ€μž…μ„ μ •μ˜ν•˜λŠ” μš©λ„λ‘œλ§Œ μ‚¬μš©ν•΄λΌ
      • ITEM 23: νƒœκ·Έ 달린 ν΄λž˜μŠ€λ³΄λ‹€ 클래슀 계측ꡬ쑰λ₯Ό ν™œμš©ν•΄λΌ
      • ITEM 24: 멀버 ν΄λž˜μŠ€λŠ” λ˜λ„λ‘ static으둜 κ΅¬ν˜„ν•΄λΌ
      • ITEM 25: ν†±λ ˆλ²¨ ν΄λž˜μŠ€λŠ” ν•œ νŒŒμΌμ— ν•˜λ‚˜λ§Œ 생성해라.
      • ITEM 26: Raw type은 μ‚¬μš©ν•˜μ§€ 마라
      • ITEM 27: 비검사 κ²½κ³ λ₯Ό μ œκ±°ν•΄λΌ
      • ITEM 28: λ°°μ—΄λ³΄λ‹€λŠ” 리슀트λ₯Ό μ‚¬μš©ν•΄λΌ
      • ITEM 29: 이왕이면 μ œλ„€λ¦­ νƒ€μž…μœΌλ‘œ λ§Œλ“€μ–΄λΌ
      • ITEM 30: 이왕이면 μ œλ„€λ¦­ λ©”μ„œλ“œλ‘œ λ§Œλ“€μ–΄λΌ
      • ITEM 31 : ν•œμ •μ  μ™€μΌλ“œμΉ΄λ“œλ₯Ό μ‚¬μš©ν•΄ API μœ μ—°μ„±μ„ 높여라
      • ITEM 32: μ œλ„€λ¦­κ³Ό κ°€λ³€μΈμˆ˜λ₯Ό ν•¨κ»˜ μ“Έ λ•ŒλŠ” 신쀑해라
      • ITEM 33: νƒ€μž… μ•ˆμ „ 이쒅 μ»¨ν…Œμ΄λ„ˆλ₯Ό 고렀해라
      • ITEM 34: int μƒμˆ˜ λŒ€μ‹  μ—΄κ±° νƒ€μž…μ„ μ‚¬μš©ν•΄λΌ
      • ITEM 35: ordinal λ©”μ„œλ“œ λŒ€μ‹  μΈμŠ€ν„΄μŠ€ ν•„λ“œλ₯Ό μ‚¬μš©ν•΄λΌ
      • ITEM 36: λΉ„νŠΈ ν•„λ“œ λŒ€μ‹  EnumSet을 μ‚¬μš©ν•΄λΌ
      • ITEM 37: ordinal 인덱싱 λŒ€μ‹  EnumMap을 μ‚¬μš©ν•΄λΌ
      • TEM 38 : ν™•μž₯ν•  수 μžˆλŠ” μ—΄κ±°νƒ€μž…μ΄ ν•„μš”ν•˜λ©΄ μΈν„°νŽ˜μ΄μŠ€λ₯Ό μ‚¬μš©ν•΄λΌ
      • ITEM 39: λͺ…λͺ… νŒ¨ν„΄λ³΄λ‹€ μ• λ„ˆν…Œμ΄μ…˜μ„ μ‚¬μš©ν•΄λΌ
      • ITEM 40: @Override μ–΄λ…Έν…Œμ΄μ…˜μ„ μΌκ΄€λ˜κ²Œ μ‚¬μš©ν•΄λΌ
      • ITEM 41: μ •μ˜ν•˜λ €λŠ” 것이 νƒ€μž…μ΄λΌλ©΄ 마컀 μΈν„°νŽ˜μ΄μŠ€λ₯Ό μ‚¬μš©ν•΄λΌ
      • ITEM 42: 읡λͺ… ν΄λž˜μŠ€λ³΄λ‹€λŠ” λžŒλ‹€λ₯Ό μ‚¬μš©ν•΄λΌ
      • ITEM 43: λžŒλ‹€λ³΄λ‹€λŠ” λ©”μ„œλ“œ μ°Έμ‘°λ₯Ό μ‚¬μš©ν•΄λΌ
      • ITEM 44: ν‘œμ€€ ν•¨μˆ˜ν˜• μΈν„°νŽ˜μ΄μŠ€λ₯Ό μ‚¬μš©ν•΄λΌ
      • ITEM 45: μŠ€νŠΈλ¦Όμ€ μ£Όμ˜ν•΄μ„œ μ‚¬μš©ν•΄λΌ
      • ITEM 46: μŠ€νŠΈλ¦Όμ—μ„œ λΆ€μž‘μš© μ—†λŠ” ν•¨μˆ˜λ₯Ό μ‚¬μš©ν•΄λΌ
      • ITEM 47: λ°˜ν™˜ νƒ€μž…μœΌλ‘œλŠ” μŠ€νŠΈλ¦Όλ³΄λ‹€ μ»¬λ ‰μ…˜μ΄ λ‚«λ‹€.
      • ITEM 48: 슀트림 λ³‘λ ¬ν™”λŠ” μ£Όμ˜ν•΄μ„œ μ‚¬μš©ν•΄λΌ
      • ITEM 49: λ§€κ°œλ³€μˆ˜κ°€ μœ νš¨ν•œμ§€ 검사해라
      • ITEM 50: μ μ‹œμ— 방어적 볡사본을 λ§Œλ“€μ–΄λΌ
      • ITEM 51: λ©”μ„œλ“œ μ‹œκ·Έλ‹ˆμ²˜λ₯Ό μ‹ μ€‘νžˆ 섀계해라
      • ITEM 52: λ‹€μ€‘μ •μ˜λŠ” μ‹ μ€‘νžˆ μ‚¬μš©ν•΄λΌ
      • ITEM 53: κ°€λ³€μΈμˆ˜λŠ” μ‹ μ€‘νžˆ μ‚¬μš©ν•΄λΌ
      • ITEM 54: null이 μ•„λ‹Œ, 빈 μ»¬λ ‰μ…˜μ΄λ‚˜ 배열을 λ°˜ν™˜ν•΄λΌ
      • ITEM 55: Optional λ°˜ν™˜μ€ μ‹ μ€‘ν•˜κ²Œ 해라
      • ITEM 56: 곡개된 API μš”μ†Œμ—λŠ” 항상 주석을 μž‘μ„±ν•΄λΌ
      • ITEM 57: μ§€μ—­λ³€μˆ˜μ˜ λ²”μœ„λ₯Ό μ΅œμ†Œν™”ν•΄λΌ
      • ITEM 58: 전톡적인 for λ¬Έλ³΄λ‹€λŠ” for-each문을 μ‚¬μš©ν•΄λΌ
      • ITEM 59: 라이브러리λ₯Ό 읡히고 μ‚¬μš©ν•΄λΌ
      • ITEM 60: μ •ν™•ν•œ 닡이 ν•„μš”ν•˜λ‹€λ©΄ float와 double은 피해라
      • ITEM 61: λ°•μ‹±λœ κΈ°λ³Έ νƒ€μž…λ³΄λ‹€λŠ” κΈ°λ³Έ νƒ€μž…μ„ μ‚¬μš©ν•΄λΌ
      • ITEM 62: λ‹€λ₯Έ νƒ€μž…μ΄ μ μ ˆν•˜λ‹€λ©΄ λ¬Έμžμ—΄ μ‚¬μš©μ„ 피해라
      • ITEM 63: λ¬Έμžμ—΄ 연결은 λŠλ¦¬λ‹ˆ μ£Όμ˜ν•΄λΌ
      • ITEM 64: κ°μ²΄λŠ” μΈν„°νŽ˜μ΄μŠ€λ₯Ό μ‚¬μš©ν•΄ 참쑰해라
      • ITEM 65: λ¦¬ν”Œλ ‰μ…˜λ³΄λ‹€λŠ” μΈν„°νŽ˜μ΄μŠ€λ₯Ό μ‚¬μš©ν•΄λΌ
      • ITEM 66: λ„€μ΄ν‹°λΈŒ λ©”μ„œλ“œλŠ” μ‹ μ€‘νžˆ μ‚¬μš©ν•΄λΌ
      • ITEM 67: μ΅œμ ν™”λŠ” μ‹ μ€‘νžˆ 해라
      • ITEM 68: 일반적으둜 ν†΅μš©λ˜λŠ” λͺ…λͺ… κ·œμΉ™μ„ 따라라
    • 객체지ν–₯ 섀계 원칙(SOLID)
    • λ””μžμΈνŒ¨ν„΄
      • Strategy Pattern
      • Template Method Pattern
      • Factory Method Pattern
      • Singleton
      • Delegation
      • Proxy
      • Adapter Pattern
    • μ‹€μŠ΅
      • μΈν„°νŽ˜μ΄μŠ€ μ‹€μŠ΅ - Vehicle
      • μΈν„°νŽ˜μ΄μŠ€ μ‹€μŠ΅ - Remote
      • GUI μ‹€μŠ΅ - Calculator
      • GUI μ‹€μŠ΅ - button
      • GUI μ‹€μŠ΅ - lotto
      • Thread μ‹€μŠ΅ - μ’Œμ„μ˜ˆμ•½, 메세지보내기
    • Jar vs War
  • λ°μ΄ν„°λ² μ΄μŠ€
    • KEY
    • Index
    • Transaction
    • Trigger
    • Procedure / Function
    • Package
    • λ°μ΄ν„°λ² μ΄μŠ€ 배움터
      • λ°μ΄ν„°λ² μ΄μŠ€ μ‹œμŠ€ν…œ
      • 관계데이터 λͺ¨λΈ
      • κ΄€κ³„λŒ€μˆ˜μ™€ SQL
    • MySQL
      • Databaseλž€
      • MySQL μ‹œμž‘ν•˜κΈ°
      • MySQL Database
      • MySQL Table
      • CRUD
      • κ΄€κ³„ν˜• λ°μ΄ν„°λ² μ΄μŠ€
      • Server와 Client
    • PostgreSQL
    • NoSQL
      • Install Cassandra on mac
      • Cassandraλž€?
      • NiFiλž€
  • Algorithm
    • String
    • Recursion
    • Dynamic Programming
    • Array, Struct, Pointer
    • Math
    • Sort
    • List
    • Stack
    • Queue
    • Graph
    • Tree
    • Maze
    • AVL
    • μ΄μ§„νƒμƒ‰νŠΈλ¦¬(Binary Search Tree)
    • DFS와 BFS
    • λ‹€μ΅μŠ€νŠΈλΌ μ•Œκ³ λ¦¬μ¦˜(Dijkstra's Algorithm)
    • Red-Black 트리
    • A* μ•Œκ³ λ¦¬μ¦˜
    • Heap
    • Huffman Coding
    • Priority Queue
    • Bellman-Ford μ•Œκ³ λ¦¬μ¦˜
    • C++
      • Class
      • STL
        • STL pair
        • STL Container - Associate Container
        • STL Container - Sequence Container
        • STL Container - Container Adapter
  • JavaScript
    • JABASCRIPT BASIC
    • Shallow Copy vs Deep Copy
    • OBJECT MODEL
    • NODE
    • 동기 처리 vs 비동기 처리
    • AJAX
    • CALLBACK
    • PROMISE
    • DEFERRER
    • UNDERSCORE
    • WEBPACK
    • SCOPE
    • EXECUTION CONTEXT
    • Image Object
    • BFCacheλž€?
    • history.scrollRestoration
    • Intersection Observer
    • JWT - JSON Web Token
    • HTML vs JSON
  • Vue.js
    • ν™˜κ²½μ„€μ •
    • Vue.jsλž€?
    • Vue Instance
    • Vue Component
    • Vue Router
    • HTTP 톡신
    • Template
    • Single File Component
    • Vue Animation
    • Vuex
    • Djnago와 μ—°λ™ν•˜κΈ°
  • Backbone.js
    • Model
    • Collection
    • Sync
    • view
  • Node.js
    • Doit! - λ…Έλ“œλ‘œ λ§Œλ“€ 수 μžˆλŠ” λŒ€ν‘œμ μΈ μ„œλ²„μ™€ μš©λ„
    • Doit! - λ…Έλ“œμ— λŒ€ν•΄ μ•Œμ•„λ³΄κ³  개발 도ꡬ μ„€μΉ˜ν•˜κΈ°
    • Doit! - λ…Έλ“œ κ°„λ‹¨ν•˜κ²Œ μ‚΄νŽ΄λ³΄κΈ°
    • Doit! - λ…Έλ“œμ˜ μžλ°”μŠ€ν¬λ¦½νŠΈμ™€ μΉœν•΄μ§€κΈ°
    • Doit! - λ…Έλ“œμ˜ κΈ°λ³Έ κΈ°λŠ₯ μ•Œμ•„λ³΄κΈ°
    • Doit! - μ›Ή μ„œλ²„ λ§Œλ“€κΈ°
    • Doit! - λ°μ΄ν„°λ² μ΄μŠ€ μ‚¬μš©ν•˜κΈ°
    • Doit! - μ΅μŠ€ν”„λ ˆμŠ€ ν”„λ‘œμ νŠΈλ₯Ό λͺ¨λ“ˆν™”ν•˜κΈ°
    • Doit! - λ·° ν…œν”Œλ¦Ώ μ μš©ν•˜κΈ°
    • Doit! - 패슀포트둜 μ‚¬μš©μž μΈμ¦ν•˜κΈ°
    • Doit! - μ±„νŒ…μ„œλ²„ λ§Œλ“€κΈ°
    • Doit! - JSON-RPC μ„œλ²„ λ§Œλ“€κΈ°
  • Python
    • Warning-Could not import the lzma module
    • Pandas
      • Pandas 자료ꡬ쑰
      • Pandas 데이터 μž…μΆœλ ₯
      • DataFrame Data μ‚΄νŽ΄λ³΄κΈ°
      • μ‹œκ°ν™” 도ꡬ - Matplotlib
  • ML
    • μΆ”μ²œ μ‹œμŠ€ν…œ
      • Collaborative Filtering
      • Matrix Factorization
  • Django
    • Basic
      • ν™˜κ²½μ„€μ •
      • About Django
      • Start Django Project
      • Secret Key κ΄€λ¦¬ν•˜κΈ°
      • Settings λΆ„λ¦¬ν•˜κΈ°
      • Django App
      • Django View & URL (1)
      • Django Model
        • MySQL 연동
      • Django Admin
      • Django View & URL (2)
      • Django Template
      • Django Template & View & URL
      • Django Static
      • Django form
    • Advanced
      • Django Generic View
      • Django Automated Testing
      • Django Extenstion Template
      • Django Model Package
      • Django OpenSSL setting
    • REST framework
      • Rest API
      • Serializers
      • ViewSet
    • Error
      • ν™˜κ²½μ„€μ • zlib 였λ₯˜λ°œμƒ
      • ModuleNotFoundError
    • νŒ¨ν‚€μ§€
      • django-debug-toolbar
    • Vue.js μ—°λ™ν•˜κΈ°
  • Ruby
    • variable & input/output
    • 쑰건문
    • 반볡문
    • Array & Hash
    • Method
    • Proc&Lamda
    • Class
  • Ruby on Rails
    • Scaffolding
    • Controller
    • Model
    • Model-M:N relation
    • Model Validation
    • 멋사 10μ£Όμ°¨ μˆ˜μ—…(Tip)
  • HTML/CSS
    • Udacity - Intro to HTML/CSS
    • Udacity - Responsive Web Design
    • Udacity - Responsive Images
    • HTML Basic
    • CSS Basic
    • HTML5 Sementic Tag
    • HTML ν…μŠ€νŠΈ κ΄€λ ¨ νƒœκ·Έλ“€
    • HTML5 λ©€ν‹°λ―Έλ””μ–΄
    • HTML 폼 κ΄€λ ¨ νƒœκ·Έλ“€
    • ν…μŠ€νŠΈ κ΄€λ ¨ μŠ€νƒ€μΌ
    • 색상과 배경을 μœ„ν•œ μŠ€νƒ€μΌ
    • λ ˆμ΄μ•„μ›ƒμ„ μœ„ν•œ μŠ€νƒ€μΌ
    • CSS 포지셔닝
    • λ‹€μž¬λ‹€λŠ₯ν•œ CSS3 μ„ νƒμž
    • CSS와 μ• λ‹ˆλ©”μ΄μ…˜
    • λ°˜μ‘ν˜• μ›Ήμ΄λž€?
  • OS(운영체제)
    • Linux
      • Daemon
      • Cron
      • ν”„λ‘œμ„ΈμŠ€ κ΄€λ ¨ λͺ…λ Ήμ–΄
      • ν…μŠ€νŠΈ 파일 λͺ…λ Ήμ–΄
  • Network
    • λ„€νŠΈμ›Œν¬ κΈ°λ³Έ κ°œλ…
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  • λžŒλ‹€λž€?
  • λžŒλ‹€μ‹ κΈ°λ³Έ 문법
  • νƒ€κ²Ÿ νƒ€μž…κ³Ό ν•¨μˆ˜μ  μΈν„°νŽ˜μ΄μŠ€
  • @FunctionallInterface ν•¨μˆ˜μ  μΈν„°νŽ˜μ΄μŠ€
  • 맀개 λ³€μˆ˜μ™€ 리턴값이 μ—†λŠ” λžŒλ‹€μ‹
  • 맀개 λ³€μˆ˜κ°€ μžˆλŠ” λžŒλ‹€μ‹
  • 리턴값이 μžˆλŠ” λžŒλ‹€μ‹
  • 클래슀 멀버와 둜컬 λ³€μˆ˜ μ‚¬μš©
  • 클래슀 멀버 μ‚¬μš©
  • 둜컬 λ³€μˆ˜ μ‚¬μš©

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  1. Java
  2. Basic

Lambda

ν•¨μˆ˜ν˜• ν”„λ‘œκ·Έλž˜λ°μ€ λ³‘λ ¬μ²˜λ¦¬μ™€ 이벀트 μ§€ν–₯ ν”„λ‘œκ·Έλž˜λ°μ— μ ν•©ν•˜κΈ° λ•Œλ¬Έμ— λΆ€κ°λ˜κ³ μžˆλ‹€. μžλ°”λŠ” ν•¨μˆ˜μ  ν”„λ‘œκ·Έλž˜λ°μ„ μœ„ν•΄ λžŒλ‹€μ‹μ„ λ„μž…ν–ˆλ‹€.

λžŒλ‹€μ‹μ€ 읡λͺ… ν•¨μˆ˜λ₯Ό μƒμ„±ν•˜κΈ° μœ„ν•œ μ‹μœΌλ‘œ 객체 μ§€ν–₯ μ–Έμ–΄λ³΄λ‹€λŠ” ν•¨μˆ˜ μ§€ν–₯ 언어에 가깝닀.

  1. μžλ°” μ½”λ“œκ°€ 맀우 κ°„κ²° 해짐

  2. μ»¬λ ‰μ…˜μ˜ μš”μ†Œλ₯Ό ν•„ν„°λ§ν•˜κ±°λ‚˜ λ§€ν•‘ν•΄ μ›ν•˜λŠ” κ²°κ³Όλ₯Ό μ‰½κ²Œ 집계할 수 있음

λžŒλ‹€λž€?

LambdaλŠ” λ©”μ„œλ“œλ₯Ό ν•˜λ‚˜μ˜ μ‹μœΌλ‘œ ν‘œν˜„ν•œ κ²ƒμœΌλ‘œ, 읡λͺ…λ©”μ„œλ“œ 생성 문법이라 λ³Ό 수 μžˆλ‹€. 즉, λ©”μ„œλ“œλͺ…없이 κ΅¬ν˜„λΆ€λ§ŒμœΌλ‘œ μ„ μ–Έν•œ 것이닀. ν•˜μ§€λ§Œ Java의 λ©”μ„œλ“œλŠ” λ©”μ„œλ“œ 자체둜 혼자 μ„ μ–Έν•˜μ—¬ 쓰일 수 μ—†μœΌλ©°, 무쑰건 Class κ΅¬μ„±λ©€λ²„λ‘œ μ„ μ–Έλ˜μ–΄μ•Όν•œλ‹€. Lambdaλ₯Ό ν†΅ν•΄μ„œ μƒμ„±λ˜λŠ” 것은 λ©”μ„œλ“œ μžμ²΄κ°€ μ•„λ‹Œ μ‹€ν–‰λ¬Έ(λ©”μ„œλ“œ)λ₯Ό κ°€μ§„ 객체이닀. λžŒλ‹€μ‹μ€ 일반적인 객체가 μ•„λ‹Œ μΈν„°νŽ˜μ΄μŠ€λ₯Ό κ΅¬ν˜„ν•œ 읡λͺ…κ΅¬ν˜„κ°μ²΄λ₯Ό μƒμ„±ν•œλ‹€.

λžŒλ‹€μ‹ -> λ§€κ°œλ³€μˆ˜λ₯Ό κ°€μ§„ μ½”λ“œ 블둝 -> 읡λͺ…κ΅¬ν˜„κ°μ²΄

λžŒλ‹€μ‹μ˜ ν˜•νƒœλŠ” 맀개 λ³€μˆ˜λ₯Ό κ°€μ§„ μ½”λ“œ λΈ”λ‘μ΄μ§€λ§Œ, λŸ°νƒ€μž„ μ‹œμ— 읡λͺ… κ΅¬ν˜„ 객체λ₯Ό 생성

Runnable runnable = new Runnable(){ //읡λͺ…κ΅¬ν˜„κ°μ²΄
    public void run(){...}
};
Runnable runnable = () -> {...}; //λžŒλ‹€μ‹

λžŒλ‹€μ‹μ€ (λ§€κ°œλ³€μˆ˜)->{μ‹€ν–‰μ½”λ“œ} 의 ν˜•νƒœλ‘œ μž‘μ„±λœλ‹€.

λžŒλ‹€μ‹ κΈ°λ³Έ 문법

(νƒ€μž… λ§€κ°œλ³€μˆ˜, ...)->{μ‹€ν–‰λ¬Έ; ...}
  • (νƒ€μž… λ§€κ°œλ³€μˆ˜, ...) : 였λ₯Έμͺ½ μ€‘κ΄„ν˜Έ {}λ₯Ό μ‹€ν–‰ν•˜κΈ° μœ„ν•΄ ν•„μš”ν•œ 값을 μ œκ³΅ν•˜λŠ” μ—­ν• , λ§€κ°œλ³€μˆ˜ 이름은 κ°œλ°œμžκ°€ 자유둭게 쀄 수 μžˆλ‹€.

  • -> : 맀개 λ³€μˆ˜λ₯Ό μ΄μš©ν•΄μ„œ μ€‘κ΄„ν˜Έ{} λ₯Ό μ‹€ν–‰

(int a)->{System.out.println(a);}

맀개 λ³€μˆ˜ νƒ€μž…μ€ λŸ°νƒ€μž„μ‹œμ— λŒ€μž…λ˜λŠ” 값에 따라 μžλ™μœΌλ‘œ 인식될 수 있기 λ•Œλ¬Έμ— λžŒλ‹€μ‹μ—μ„œλŠ” 맀개 λ³€μˆ˜μ˜ νƒ€μž…μ„ 일반적으둜 μ–ΈκΈ‰ν•˜μ§€ μ•ŠλŠ”λ‹€.

(a)->{System.out.println(a);}

ν•˜λ‚˜μ˜ λ§€κ°œλ³€μˆ˜λ§Œ μžˆλ‹€λ©΄ () λ₯Ό μƒλž΅ν•  수 있고, ν•˜λ‚˜μ˜ μ‹€ν–‰λ¬Έλ§Œ μžˆλ‹€λ©΄ {} 도 μƒλž΅ν•  수 μžˆλ‹€.

a -> System.out.println(a);

λ§Œμ•½ λ§€κ°œλ³€μˆ˜κ°€ μ—†λ‹€λ©΄ λΉˆκ΄„ν˜Έ() λ₯Ό λ°˜λ“œμ‹œ μ‚¬μš©ν•΄μ•Όν•œλ‹€.

(x,y) -> { return x+y; }

싀행문을 μ‹€ν–‰ν•˜κ³  결과값을 λ¦¬ν„΄ν•΄μ•Όν•œλ‹€λ©΄ μœ„μ™€ 같이 return문으둜 결과값을 μ§€μ •ν•  수 μžˆλ‹€.

(x,y) -> x+y

λ§Œμ•½ {} 에 return문만 μžˆλŠ” κ²½μš°μ—λŠ” μœ„μ™€ 같이 return문을 μ‚¬μš©ν•˜μ§€ μ•Šκ³  μž‘μ„±ν•  수 μžˆλ‹€.

νƒ€κ²Ÿ νƒ€μž…κ³Ό ν•¨μˆ˜μ  μΈν„°νŽ˜μ΄μŠ€

μΈν„°νŽ˜μ΄μŠ€ λ³€μˆ˜ = λžŒλ‹€μ‹;

λžŒλ‹€μ‹μ€ μΈν„°νŽ˜μ΄μŠ€ λ³€μˆ˜μ— λŒ€μž…λœλ‹€. 즉, λžŒλ‹€μ‹μ€ μΈν„°νŽ˜μ΄μŠ€μ˜ 읡λͺ… κ΅¬ν˜„ 객체λ₯Ό μƒμ„±ν•œλ‹€λŠ” λœ»μ΄λ‹€. μΈν„°νŽ˜μ΄μŠ€λŠ” 직접 객체화할 수 μ—†κΈ° λ•Œλ¬Έμ— 읡λͺ… κ΅¬ν˜„ 클래슀λ₯Ό μƒμ„±ν•˜κ³  κ°μ²΄ν™”ν•œλ‹€. λžŒλ‹€μ‹μ€ λŒ€μž…λ  μΈν„°νŽ˜μ΄μŠ€μ˜ μ’…λ₯˜μ— 따라 μž‘μ„±λ²•μ΄ 달라지기 λ•Œλ¬Έμ— λžŒλ‹€μ‹μ΄ λŒ€μž…λ  μΈν„°νŽ˜μ΄μŠ€λ₯Ό λžŒλ‹€μ‹μ˜ νƒ€κ²Ÿνƒ€μž…(target type)이라 ν•œλ‹€.

@FunctionallInterface ν•¨μˆ˜μ  μΈν„°νŽ˜μ΄μŠ€

λžŒλ‹€μ‹μ΄ ν•˜λ‚˜μ˜ λ©”μ†Œλ“œλ₯Ό μ •μ˜ν•˜κΈ° λ•Œλ¬Έμ— 두 개 μ΄μƒμ˜ 좔상 λ©”μ†Œλ“œκ°€ μ„ μ–Έλœ μΈν„°νŽ˜μ΄μŠ€λŠ” λžŒλ‹€μ‹μ„ μ΄μš©ν•΄μ„œ κ΅¬ν˜„κ°μ²΄λ₯Ό 생성할 수 μ—†λ‹€. 즉, ν•˜λ‚˜μ˜ 좔상 λ©”μ†Œλ“œκ°€ μ„ μ–Έλœ μΈν„°νŽ˜μ΄μŠ€λ§Œμ΄ λžŒλ‹€μ‹μ˜ νƒ€κ²Ÿ νƒ€μž…μ΄ 될 수 있으며, 이λ₯Ό ν•¨μˆ˜μ  μΈν„°νŽ˜μ΄μŠ€λΌ ν•œλ‹€. μΈν„°νŽ˜μ΄μŠ€ μ„ μ–Έμ‹œ @FunctionallInterface μ–΄λ…Έν…Œμ΄μ…˜μ„ 뢙이면 μ»΄νŒŒμΌλŸ¬κ°€ 두 개 μ΄μƒμ˜ 좔상 λ©”μ†Œλ“œκ°€ μ„ μ–Έλ˜μ§€ μ•Šλ„λ‘ 체킹해쀀닀.

@FunctionalInterface
public interface MyFunctionalInterface{
    public void methodA();
    public void methodB(); // 컴파일 였λ₯˜
}

맀개 λ³€μˆ˜μ™€ 리턴값이 μ—†λŠ” λžŒλ‹€μ‹

@FunctionalInterface
public interface MyFunctionalInterface{
    public void method();
}
MyFunctionalInterface fi = ()->{...}

method()κ°€ λ§€κ°œλ³€μˆ˜ 값을 κ°€μ§€μ§€ μ•ŠκΈ° λ•Œλ¬Έμ— λžŒλ‹€μ‹μ—μ„œ λ§€κ°œλ³€μˆ˜κ°€ μ—†λ‹€.

fi.method();

λžŒλ‹€μ‹μ΄ λŒ€μž…λœ μΈν„°νŽ˜μ΄μŠ€μ˜ μ°Έμ‘° λ³€μˆ˜λŠ” μœ„μ™€ 같이 method()λ₯Ό ν˜ΈμΆœν•  수 있으며, ν˜ΈμΆœμ€ λžŒλ‹€μ‹μ˜ {...} λ₯Ό μ‹€ν–‰μ‹œν‚¨λ‹€.

맀개 λ³€μˆ˜κ°€ μžˆλŠ” λžŒλ‹€μ‹

@FunctionalInterface
public interface MyFunctionalInterface{
    public void method(int x);
}
MyFunctionalInterface fi = (x)->{...}
MyFunctionalInterface fi = x -> {...}
fi.method(5);

리턴값이 μžˆλŠ” λžŒλ‹€μ‹

@FunctionalInterface
public interface MyFunctionalInterface{
    public int method(int x, int y);
}
MyFunctionalInterface fi = (x, y)->{ ... ; return κ°’; }
MyFunctionalInterface fi = (x, y)->{ 
    return x + y;
}
MyFunctionalInterface fi = (x, y) -> x + y;
int result = fi.method(2,5);

클래슀 멀버와 둜컬 λ³€μˆ˜ μ‚¬μš©

λžŒλ‹€μ‹μ˜ μ‹€ν–‰ λΈ”λ‘μ—λŠ” 클래슀의 멀버(ν•„λ“œ, λ©”μ†Œλ“œ) 및 둜컬 λ³€μˆ˜λ₯Ό μ‚¬μš©ν•  수 μžˆλ‹€.

클래슀 멀버 μ‚¬μš©

클래슀의 멀버인 ν•„λ“œμ™€ λ©”μ†Œλ“œλŠ” μ œμ•½μ—†μ΄ μ‚¬μš©ν•  수 μžˆλ‹€. ν•˜μ§€λ§Œ this ν‚€μ›Œλ“œλ₯Ό μ‚¬μš©ν•  λ•ŒλŠ” μ£Όμ˜κ°€ ν•„μš”ν•˜λ‹€.

일반적으둜 읡λͺ… 객체 λ‚΄λΆ€μ—μ„œ thisλŠ” 읡λͺ… 객체의 μ°Έμ‘°μ΄μ§€λ§Œ, λžŒλ‹€μ‹μ—μ„œ thisλŠ” λ‚΄λΆ€μ μœΌλ‘œ μƒμ„±λ˜λŠ” λžŒλ‹€μ‹μ„ μ‹€ν–‰ν•œ 객체의 참쑰이닀.

public interface MyFunctionalInterface{
    public void method();
}
public class UsingThis{
    public int outterField = 10;

    class Inner{
        int innerField = 20;

        void method(){
            //λžŒλ‹€μ‹
            MyFunctionalInterface fi = ()->{
                // λ°”κΉ₯ 객체의 μ°Έμ‘°λ₯Ό μ–»κΈ° μœ„ν•΄μ„œλŠ” 클래슀λͺ….thisμ‚¬μš©
                System.out.println("outterField : "+ UsingThis.this.outterField);
                // λžŒλ‹€μ‹ λ‚΄λΆ€μ—μ„œ thisλŠ” Inner 객체λ₯Ό 잠쑰
                System.out.println("innerField : "+ this.innerField);
            };
            fi.method();
        }
    }
}
public class UsingThisEx {
    public static void main(String... args){
        UsingThis usingThis = new UsingThis();
        UsignThis.Inner inner = usingThis.new Inner();
        inner.method();
    }
}

둜컬 λ³€μˆ˜ μ‚¬μš©

λžŒλ‹€μ‹μ€ λ©”μ†Œλ“œ λ‚΄λΆ€μ—μ„œ 주둜 μž‘μ„±λ˜λ―€λ‘œ 둜컬 읡λͺ… κ΅¬ν˜„ 객체λ₯Ό μƒμ„±μ‹œν‚¨λ‹€κ³  λ΄μ•Όν•œλ‹€. λžŒλ‹€μ‹μ—μ„œ λ°”κΉ₯ 클래슀의 ν•„λ“œλ‚˜ λ©”μ†Œλ“œλŠ” μ œν•œ 없이 μ‚¬μš©ν•  수 μžˆμœΌλ‚˜, λ©”μ†Œλ“œμ˜ λ§€κ°œλ³€μˆ˜ λ˜λŠ” 둜컬 λ³€μˆ˜λ₯Ό μ‚¬μš©ν•˜λ©΄ 이 두 λ³€μˆ˜λŠ” final νŠΉμ„±μ„ κ°€μ Έμ•Όν•œλ‹€.

맀개 λ³€μˆ˜ λ˜λŠ” 둜컬 λ³€μˆ˜λ₯Ό λžŒλ‹€μ‹μ—μ„œ μ½λŠ” 것은 ν—ˆμš©λ˜μ§€λ§Œ, λžŒλ‹€μ‹ λ‚΄λΆ€ λ˜λŠ” μ™ΈλΆ€μ—μ„œ λ³€κ²½ν•  수 μ—†λ‹€.

public interface MyFunctionalInterface{
    public void method();
}
public class UsingLocalVariable{
    // argλŠ” final νŠΉμ„±
    void method(int arg){
        int localVar = 40; // localVal final νŠΉμ„±

        // finalνŠΉμ„±λ•Œλ¬Έμ— λ³€κ²½ λΆˆκ°€
        // arg = 31;
        // localVal = 20;

        // λžŒλ‹€μ‹
        MyFunctionalInterface fi = () -> {
            System.out.println("arg: " + arg);
            System.out.println("localVal: " + localVal);
        };
        fi.method();
    }
}
PreviousGenericNextCollection - List, Set

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[ λ₯Ό μ°Έμ‘°]

09. 쀑첩 ν΄λž˜μŠ€μ™€ 쀑첩 μΈν„°νŽ˜μ΄μŠ€ - 읡λͺ…κ°μ²΄μ˜ 둜컬 λ³€μˆ˜ μ‚¬μš©