Contenu du cours
Stream API
Stream API
1. Fundamentals and Functional Capabilities of Stream API
ArchitecturePrinciplesWhat Is a Functional Interface?Predicate: Data FilteringChallenge: Filtering Corporate Email AddressesFunction: Data TransformationChallenge: Income Tax CalculationComparable: Natural Ordering of DataComparator: Custom Comparison of DataChallenge: Sorting Employees Consumer: Processing Data Supplier: Data GenerationBi-versions of Functional InterfacesChallenge: Filtering Users by Two CriteriaBinaryOperator: Combining Two Values
2. Intermediate Operations in Stream API
Transforming Elements with the map() MethodFiltering Elements with the filter() MethodChallenge: Factory Product FilteringWorking with Nested Structures with the flatMap() MethodArranging Items in Order with the sorted() MethodChallenge: Selecting the Best Cars on the Production LineEliminating Duplicates with the distinct() MethodChallenge: Factory Quality ControlRestricting and Skipping Elements with the limit() and skip() MethodsChallenge: Finding the Top 3 Hardest-Working EmployeesIntermediate Processing with the peek() Method
3. Terminal Operations in the Stream API
collect() Gathering Stream Elements into a CollectionChallenge: Build a Custom Collector for Category CountingCollectors Utility Class for Stream APIProcessing Elements with the forEach() MethodHandling Values with the Optional ClassAggregating Elements with the reduce() MethodChallenge: Calculating Total Cost with Discounts and TaxCalculating Stream Statistics with count(), max(), and min()Retrieving Stream Summary Metrics with summaryStatistics() MethodRetrieving Elements from a Stream with findFirst() and findAny()Challenge: Selecting Random Products Within a CategoryChecking Stream Elements Against a Condition with allMatch()Challenge: Ensuring Fast Delivery for Expensive Products
4. Practical Applications of Stream API
Challenge: Build a Custom Collector for Category Counting
Tâche
Swipe to start coding
You need to implement a custom Collector that processes a list of products and counts how many products belong to each category.
- In the
supplier()method, return a newHashMap. - In the
accumulator()method, call theget()method on theproductmap to retrieve the value of the"category"key and pass it as the first parameter of themerge()method. - For the second parameter in the same method, provide the initial value (
1). - In the
combiner()method, pass thekeyofmap2as the first parameter of themerge()method. - For the second parameter in the same method, pass the
valueof themap2. - In the
finisher()method, return themapwithout modifying it using a lambda. - In the
characteristics()method, return a set that ensures the collection remains unchanged (IDENTITY_FINISH). - In the
collect()method, pass the implementation of theCollectorinterface (CategoryCountCollector).
Solution
solution
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Section 3. Chapitre 2
Challenge: Build a Custom Collector for Category Counting
Tâche
Swipe to start coding
You need to implement a custom Collector that processes a list of products and counts how many products belong to each category.
- In the
supplier()method, return a newHashMap. - In the
accumulator()method, call theget()method on theproductmap to retrieve the value of the"category"key and pass it as the first parameter of themerge()method. - For the second parameter in the same method, provide the initial value (
1). - In the
combiner()method, pass thekeyofmap2as the first parameter of themerge()method. - For the second parameter in the same method, pass the
valueof themap2. - In the
finisher()method, return themapwithout modifying it using a lambda. - In the
characteristics()method, return a set that ensures the collection remains unchanged (IDENTITY_FINISH). - In the
collect()method, pass the implementation of theCollectorinterface (CategoryCountCollector).
Solution
solution
Passez à un bureau pour une pratique réelleContinuez d'où vous êtes en utilisant l'une des options ci-dessousTout était clair ?
Merci pour vos commentaires !
Section 3. Chapitre 2
Passez à un bureau pour une pratique réelleContinuez d'où vous êtes en utilisant l'une des options ci-dessous