List of Listings

Chapter 2. Passing code with behavior parameterization

Listing 2.1. Behavior parameterization: filtering apples with predicates

Chapter 3. Lambda expressions

Listing 3.1. Valid lambda expressions in Java 8

Listing 3.2. Working with a Predicate

Listing 3.3. Working with a Consumer

Listing 3.4. Working with a Function

Chapter 4. Introducing streams

Listing 4.1. Collections: external iteration with a for-each loop

Listing 4.2. Collections: external iteration using an iterator behind the scenes

Listing 4.3. Streams: internal iteration

Chapter 5. Working with streams

Listing 5.1. Finds all transactions in 2011 and sort by value (small to high)

Listing 5.2. What are all the unique cities where the traders work?

Listing 5.3. Finds all traders from Cambridge and sort them by name

Listing 5.4. Returns a string of all traders’ names sorted alphabetically

Listing 5.5. Are any traders based in Milan?

Listing 5.6. Prints all transactions’ values from the traders living in Cambridge

Listing 5.7. What’s the highest value of all the transactions?

Listing 5.8. Finds the transaction with the smallest value

Chapter 6. Collecting data with streams

Listing 6.1. Grouping transactions by currency in imperative style

Listing 6.2. Multilevel grouping

Listing 6.3. Finding the highest-calorie dish in each subgroup

Listing 6.4. The Collector interface

Listing 6.5. The ToListCollector

Listing 6.6. Partitioning the first n natural numbers into primes and nonprimes

Listing 6.7. The PrimeNumbersCollector

Chapter 7. Parallel data processing and performance

Listing 7.1. Measuring performance of a function summing the first n numbers

Listing 7.2. Executing a parallel sum using the fork/join framework

Listing 7.3. The Spliterator interface

Listing 7.4. An iterative word counter method

Listing 7.5. A class to count words while traversing a stream of Characters

Listing 7.6. The WordCounterSpliterator

Chapter 10. Domain-specific languages using lambdas

Listing 10.1. Reading the error lines in a log file in imperative style

Listing 10.2. Reading the error lines in a log file in functional style

Listing 10.3. A fluent grouping collectors builder

Listing 10.4. Creating a stock trading order by using the domain object’s API directly

Listing 10.5. Creating a stock trading order with method chaining

Listing 10.6. An order builder providing a method-chaining DSL

Listing 10.7. Creating a stock-trading order with nested functions

Listing 10.8. An order builder providing a nested-function DSL

Listing 10.9. Creating a stock-trading order with function sequencing

Listing 10.10. An order builder providing a function-sequencing DSL

Listing 10.11. Creating a stock-trading order by using multiple DSL patterns

Listing 10.12. An order builder providing a DSL that mixes multiple styles

Listing 10.13. The taxes that can be applied to the order’s net value

Listing 10.14. Applying taxes to the order’s net value with a set of Boolean flags

Listing 10.15. A tax calculator that fluently defines the taxes to be applied

Listing 10.16. A tax calculator that fluently combines the tax functions to be applied

Listing 10.17. Selecting books from a database by using the jOOQ DSL

Listing 10.18. Implementing a test scenario by using Cucumber annotations

Listing 10.19. Configuring a Spring Integration flow by using the Spring Integration DSL

Chapter 11. Using Optional as a better alternative to null

Listing 11.1. The Person/Car/Insurance data model

Listing 11.2. Null-safe attempt 1: deep doubts

Listing 11.3. Null-safe attempt 2: too many exits

Listing 11.4. Redefining the Person/Car/Insurance data model by using Optional

Listing 11.5. Finding a car’s insurance company name with Optionals

Listing 11.6. Finding distinct insurance company names used by a list of persons

Listing 11.7. Converting a String to an Integer returning an optional

Listing 11.8. Reading duration from a property imperatively

Chapter 12. New Date and Time API

Listing 12.1. Creating a LocalDate and reading its values

Listing 12.2. Reading LocalDate values by using a TemporalField

Listing 12.3. Creating a LocalTime and reading its values

Listing 12.4. Creating a LocalDateTime directly or by combining a date and a time

Listing 12.5. Creating Durations and Periods

Listing 12.6. Manipulating the attributes of a LocalDate in an absolute way

Listing 12.7. Manipulating the attributes of a LocalDate in a relative way

Listing 12.8. Using the predefined TemporalAdjusters

Listing 12.9. The TemporalAdjuster interface

Listing 12.10. Creating a DateTimeFormatter from a pattern

Listing 12.11. Creating a localized DateTimeFormatter

Listing 12.12. Building a DateTimeFormatter

Listing 12.13. Applying a time zone to a point in time

Chapter 16. CompletableFuture: composable asynchronous programming

Listing 16.1. Executing a long-lasting operation asynchronously in a Future

Listing 16.2. A method to simulate a 1-second delay

Listing 16.3. Introducing a simulated delay in the getPrice method

Listing 16.4. Implementing the getPriceAsync method

Listing 16.5. Using an asynchronous API

Listing 16.6. Propagating an error inside the CompletableFuture

Listing 16.7. Creating a CompletableFuture with the supplyAsync factory method

Listing 16.8. A findPrices implementation sequentially querying all the shops

Listing 16.9. Checking findPrices correctness and performance

Listing 16.10. Parallelizing the findPrices method

Listing 16.11. Implementing the findPrices method with CompletableFutures

Listing 16.12. A custom Executor fitting the best-price-finder application

Listing 16.13. An enumeration defining the discount codes

Listing 16.14. The Discount service

Listing 16.15. Simplest findPrices implementation that uses the Discount service

Listing 16.16. Implementing the findPrices method with CompletableFutures

Listing 16.17. Combining two independent CompletableFutures

Listing 16.18. Combining two Futures in Java 7

Listing 16.19. Adding a timeout to CompletableFuture

Listing 16.20. Completing a CompletableFuture with a default value after a timeout

Listing 16.21. A method to simulate a random delay between 0.5 and 2.5 seconds

Listing 16.22. Refactoring the findPrices method to return a stream of Futures

Listing 16.23. Reacting to CompletableFuture completion

Chapter 17. Reactive programming

Listing 17.1. The Flow.Publisher interface

Listing 17.2. The Flow.Subscriber interface

Listing 17.3. The Flow.Subscription interface

Listing 17.4. The Flow.Processor interface

Listing 17.5. A Java bean conveying the currently reported temperature

Listing 17.6. A Subscription sending a stream of TempInfo to its Subscriber

Listing 17.7. A Subscriber printing the received temperatures

Listing 17.8. A main class: creating a Publisher and subscribing TempSubscriber to it

Listing 17.9. Adding an Executor to the TempSubscription

Listing 17.10. A Processor transforming temperatures from Fahrenheit to Celsius

Listing 17.11. Main class: create a Publisher and subscribe TempSubscriber to it

Listing 17.12. Creating an Observable emitting temperature once a second

Listing 17.13. An Observer printing the received temperatures

Listing 17.14. A main class printing the temperatures in New York

Listing 17.15. Using map on Observable to transform Fahrenheit into Celsius

Listing 17.16. Merging the temperatures reported for one or more towns

Listing 17.17. A main class printing the temperatures in three towns

Chapter 18. Thinking functionally

Listing 18.1. Iterative factorial

Listing 18.2. Recursive factorial

Listing 18.3. Stream factorial

Listing 18.4. Tail-recursive factorial

Chapter 19. Functional programming techniques

Listing 19.1. Implementing pattern matching to simplify an expression

Appendix B. Miscellaneous library updates

Listing B.1. LongAdder to calculate the sum of values

Listing B.2. LongAccumulator to calculate the sum of values

Listing B.3. parallelPrefix cumulates in parallel elements of an array

Appendix C. Performing multiple operations in parallel on a stream

Listing C.1. Defining a StreamForker to execute multiple operations on a stream

Listing C.2. The build method used to create ForkingStreamConsumer

Listing C.3. Futures created with the getOperationResult method

Listing C.4. A ForkingStreamConsumer to add stream elements to multiple queues

Listing C.5. A Spliterator reading the elements it traverses from a BlockingQueue

Listing C.6. Putting the StreamForker to work

Appendix D. Lambdas and JVM bytecode

Listing D.1. A Function implemented as an anonymous inner class

Listing D.2. A Function implemented with a lambda expression