Kursinhalt

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: Calculating Total Cost with Discounts and Tax

Aufgabe

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Implement a shopping cart system that calculates the total order cost, applying a discount and sales tax based on predefined conditions.

Use map() to get the total price of each product (there is a dedicated method getTotalPrice() in the Product class).
Apply reduce() to sum up all product prices.
Use a ternary operator to check if the subtotal exceeds the discount threshold (DISCOUNT_THRESHOLD) and calculate the discount. If subtotal is greater than the threshold, apply a 10% discount (DISCOUNT_PERCENTAGE); otherwise, set the discount to 0.0.
Determine the discount amount by multiplying subtotal by DISCOUNT_PERCENTAGE.
Calculate the pre-tax amount (preTaxAmount) by subtracting discount from subtotal.
Compute the sales tax (tax) by multiplying preTaxAmount by the sales tax rate (SALES_TAX).
Return the final total, calculated as preTaxAmount + tax.

Lösung

solution

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Abschnitt 3. Kapitel 7

Challenge: Calculating Total Cost with Discounts and Tax

Aufgabe

Swipe to start coding

Implement a shopping cart system that calculates the total order cost, applying a discount and sales tax based on predefined conditions.

Use map() to get the total price of each product (there is a dedicated method getTotalPrice() in the Product class).
Apply reduce() to sum up all product prices.
Use a ternary operator to check if the subtotal exceeds the discount threshold (DISCOUNT_THRESHOLD) and calculate the discount. If subtotal is greater than the threshold, apply a 10% discount (DISCOUNT_PERCENTAGE); otherwise, set the discount to 0.0.
Determine the discount amount by multiplying subtotal by DISCOUNT_PERCENTAGE.
Calculate the pre-tax amount (preTaxAmount) by subtracting discount from subtotal.
Compute the sales tax (tax) by multiplying preTaxAmount by the sales tax rate (SALES_TAX).
Return the final total, calculated as preTaxAmount + tax.

Lösung

solution

Wechseln Sie zum Desktop, um in der realen Welt zu übenFahren Sie dort fort, wo Sie sind, indem Sie eine der folgenden Optionen verwenden

War alles klar?

Danke für Ihr Feedback!

Abschnitt 3. Kapitel 7

Wechseln Sie zum Desktop, um in der realen Welt zu übenFahren Sie dort fort, wo Sie sind, indem Sie eine der folgenden Optionen verwenden