Working with streams - Java 8 in Action: Lambdas, Streams, and Functional-Style Programming - page 130

Operation Type Return

type

Type/functional
interface used

Function
descriptor

forEach Terminal void Consumer<T> T -> void

collect terminal R Collector<T, A, R>

reduce Terminal Optional<T> BinaryOperator<T> (T, T) -> T

(stateful-bounded)

count Terminal long

5.5. Putting it all into practice

In this section, you get to practice what you've learned about streams so far. We give a different
domain: traders executing transactions. You're asked by your manager to find answers to eight
queries. Can you do it? We give the solutions in section 5.5.2 , but you should try them yourself
first to get some practice.

1 . Find all transactions in the year 2011 and sort them by value (small to high).

2 . What are all the unique cities where the traders work?

3 . Find all traders from Cambridge and sort them by name.

4 . Return a string of all traders' names sorted alphabetically.

5 . Are any traders based in Milan?

6 . Print all transactions' values from the traders living in Cambridge.

7 . What's the highest value of all the transactions?

8 . Find the transaction with the smallest value.

5.5.1. The domain: Traders and Transactions

Here's the domain you'll be working with, a list of Traders and Transactions:

Trader raoul = new Trader("Raoul", "Cambridge");