Stream API

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Stream API

Stream API

1. Fundamentals and Functional Capabilities of Stream API

Architecture Principles What Is a Functional Interface?Predicate: Data Filtering Challenge: Filtering Corporate Email Addresses Function: Data Transformation Challenge: Income Tax Calculation Comparable: Natural Ordering of Data Comparator: Custom Comparison of Data Challenge: Sorting Employees Consumer: Processing Data Supplier: Data Generation Bi-versions of Functional Interfaces Challenge: Filtering Users by Two Criteria BinaryOperator: Combining Two Values

2. Intermediate Operations in Stream API

Transforming Elements with the map() Method Filtering Elements with the filter() Method Challenge: Factory Product Filtering Working with Nested Structures with the flatMap() Method Arranging Items in Order with the sorted() Method Challenge: Selecting the Best Cars on the Production Line Eliminating Duplicates with the distinct() Method Challenge: Factory Quality Control Restricting and Skipping Elements with the limit() and skip() Methods Challenge: Finding the Top 3 Hardest-Working Employees Intermediate Processing with the peek() Method

3. Terminal Operations in the Stream API

collect() Gathering Stream Elements into a Collection Challenge: Build a Custom Collector for Category Counting Collectors Utility Class for Stream API Processing Elements with the forEach() Method Handling Values with the Optional Class Aggregating Elements with the reduce() Method Challenge: Calculating Total Cost with Discounts and Tax Calculating Stream Statistics with count(), max(), and min()Retrieving Stream Summary Metrics with summaryStatistics() Method Retrieving Elements from a Stream with findFirst() and findAny()Challenge: Selecting Random Products Within a Category Checking Stream Elements Against a Condition with allMatch()Challenge: Ensuring Fast Delivery for Expensive Products

4. Practical Applications of Stream API

Real-World Examples of Using Stream API Performance in Stream API Exception Handling in Stream API Summary

Challenge: Build a Custom Collector for Category Counting

Завдання

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 new HashMap.
In the accumulator() method, call the get() method on the product map to retrieve the value of the "category" key and pass it as the first parameter of the merge() method.
For the second parameter in the same method, provide the initial value (1).
In the combiner() method, pass the key of map2 as the first parameter of the merge() method.
For the second parameter in the same method, pass the value of the map2.
In the finisher() method, return the map without 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 the Collector interface (CategoryCountCollector).

Рішення

solution

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Секція 3. Розділ 2

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Challenge: Build a Custom Collector for Category Counting

Завдання

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 new HashMap.
In the accumulator() method, call the get() method on the product map to retrieve the value of the "category" key and pass it as the first parameter of the merge() method.
For the second parameter in the same method, provide the initial value (1).
In the combiner() method, pass the key of map2 as the first parameter of the merge() method.
For the second parameter in the same method, pass the value of the map2.
In the finisher() method, return the map without 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 the Collector interface (CategoryCountCollector).

Рішення

solution

Перейдіть на комп'ютер для реальної практикиПродовжуйте з того місця, де ви зупинились, використовуючи один з наведених нижче варіантів

Все було зрозуміло?

Дякуємо за ваш відгук!

Секція 3. Розділ 2

Перейдіть на комп'ютер для реальної практикиПродовжуйте з того місця, де ви зупинились, використовуючи один з наведених нижче варіантів

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