package wen;

import java.util.*;

public class dome {
    public static void main(String[] args) {
        Trader raoul = new  Trader("Raoul", "Cambridge");
        Trader mario = new Trader("Mario", "Milan");
        Trader alan = new Trader("Alan", "Cambridge");
        Trader brian = new Trader("Brian", "Cambridge");

        List<Transaction> transactions = Arrays.asList(
                new Transaction(brian, 2011, 300),
                new Transaction(raoul, 2012, 1000),
                new Transaction(raoul, 2011, 400),
                new Transaction(mario, 2012, 710),
                new Transaction(mario, 2012, 700),
                new Transaction(alan, 2012, 950)
        );
        System.out.println("2011年的所有交易按低到高排序");
        transactions.stream()
                .filter(item->item.getYear()==2011)
                .sorted((o1,o2) -> o1.getValue() - o2.getValue())
                .forEach(System.out::println);
        System.out.println("(2) 交易员都在哪些不同的城市工作过？");
        transactions.stream()
                .map(item->item.getTrader().getCity())
                .distinct()
                .forEach(System.out::println);
        System.out.println("(3) 查找所有来自于剑桥的交易员，并按姓名排序。");
        transactions.stream()
                .filter(item->item.getTrader().getCity().equals("Cambridge"))
                .sorted(((o1, o2) -> o1.getTrader().getName().length()-o2.getTrader().getName().length()))
                .map(item->{
                    HashMap<Object, Object> hashMap = new HashMap<>();
                    hashMap.put("name",item.getTrader().getName());
                    return hashMap;
                }
                ).forEach(System.out::println);
        System.out.println("(4) 返回所有交易员的姓名字符串，按字母顺序排序");
        transactions.stream()
                .sorted(Comparator.comparing(item->item.getTrader().getName()))
                .map(item->{
                    HashMap<Object, Object> hashMap = new HashMap<>();
                    hashMap.put("name",item.getTrader().getName());
                    return hashMap;
                }
                ).forEach(System.out::println);
        System.out.println("(5) 有没有交易员是在米兰工作的？");
        transactions.stream()
                .filter(item->item.getTrader().getCity().equals("Milan"))
                .forEach(System.out::println);
        System.out.println("(6) 打印生活在剑桥的交易员的所有交易额。");
        Optional<Integer> cambridge = transactions.stream()
                .filter(item -> item.getTrader().getCity().equals("Cambridge"))
                .map(item -> item.getValue())
                .reduce((a, b) -> a + b);
        System.out.println(cambridge.get());
        System.out.println("(7) 所有交易中，最高的交易额是多少？");
        Optional<Transaction> max = transactions.stream()
                .max((o1, o2) -> o1.getValue() - o2.getValue());
        System.out.println(max.get().getValue());
        System.out.println("找到交易额最小的交易。");
        Optional<Transaction> min = transactions.stream()
                .min((o1, o2) -> o1.getValue() - o2.getValue());
        System.out.println(min.get().getValue());
    }

}
//交易员类
 class Trader {
    private final String name;
    private final String city;

    public Trader(String name, String city) {
        this.name = name;
        this.city = city;
    }

    public String getName() {
        return name;
    }

    public String getCity() {
        return city;
    }

    @Override
    public String toString() {
        return "Trader{" +
                "name='" + name + '\'' +
                ", city='" + city + '\'' +
                '}';
    }
}

//Transaction（交易记录）

 class Transaction {
    private final Trader trader;
    private final int year;
    private final int value;
    public Transaction(Trader trader, int year, int value){
        this.trader = trader;
        this.year = year;
        this.value = value;
    }
    public Trader getTrader(){
        return this.trader;
    }
    public int getYear(){
        return this.year;
    }
    public int getValue(){
        return this.value;
    }
    public String toString(){
        return "{" + this.trader + ", " +
                "year: "+this.year+", " +
                "value:" + this.value +"}";
    }
}