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iamlow/StreamAPI.java

Last active March 21, 2017 08:27
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Revisions

  1. iamlow revised this gist Mar 21, 2017. 1 changed file with 1 addition and 1 deletion.
    2 changes: 1 addition & 1 deletion StreamAPI.java
    View file
    Original file line number Diff line number Diff line change
    @@ -38,5 +38,5 @@ public static void main(String ...args) {

    // Query 8: What's the lowest value in all the transactions?
    System.out.println(transactions.stream().map(Transaction::getValue).reduce(Integer::min));
    }
    }
    }
  2. iamlow revised this gist Mar 21, 2017. 1 changed file with 26 additions and 26 deletions.
    52 changes: 26 additions & 26 deletions StreamAPI.java
    View file
    Original file line number Diff line number Diff line change
    @@ -4,39 +4,39 @@ public static void main(String ...args) {
    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)
    );

    // Query 1: Find all transactions from year 2011 and sort them by value (small to high).
    transactions.stream().filter(t -> t.getYear() == 2011).sorted(comparing(Transaction::getValue)).forEach(System.out::println);
    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)
    );

    // Query 2: What are all the unique cities where the traders work?
    transactions.stream().map(t -> t.getTrader().getCity()).distinct().forEach(System.out::println);
    // Query 1: Find all transactions from year 2011 and sort them by value (small to high).
    transactions.stream().filter(t -> t.getYear() == 2011).sorted(comparing(Transaction::getValue)).forEach(System.out::println);

    // Query 3: Find all traders from Cambridge and sort them by name.
    transactions.stream().map(Transaction::getTrader).filter(t -> t.getCity().equals("Cambridge")).distinct().sorted(comparing(Trader::getName)).forEach(System.out::println);
    // Query 2: What are all the unique cities where the traders work?
    transactions.stream().map(t -> t.getTrader().getCity()).distinct().forEach(System.out::println);

    // Query 4: Return a string of all traders’ names sorted alphabetically.
    System.out.println(transactions.stream().map(t -> t.getTrader().getName()).distinct().sorted().reduce("", (n1, n2) -> n1 + n2) + "\n");
    // Query 3: Find all traders from Cambridge and sort them by name.
    transactions.stream().map(Transaction::getTrader).filter(t -> t.getCity().equals("Cambridge")).distinct().sorted(comparing(Trader::getName)).forEach(System.out::println);

    // Query 5: Are there any trader based in Milan?
    System.out.println(transactions.stream().anyMatch(t -> t.getTrader().getCity().equals("Milan")));
    // Query 4: Return a string of all traders’ names sorted alphabetically.
    System.out.println(transactions.stream().map(t -> t.getTrader().getName()).distinct().sorted().reduce("", (n1, n2) -> n1 + n2) + "\n");

    // Query 6: Update all transactions so that the traders from Milan are set to Cambridge.
    Optional<Transaction> trans = transactions.stream().filter(t -> t.getTrader().getCity().equals("Cambridge")).findAny();
    System.out.println(trans);
    // Query 5: Are there any trader based in Milan?
    System.out.println(transactions.stream().anyMatch(t -> t.getTrader().getCity().equals("Milan")));

    // Query 7: What's the highest value in all the transactions?
    System.out.println(transactions.stream().map(Transaction::getValue).reduce(Integer::max));
    // Query 6: Update all transactions so that the traders from Milan are set to Cambridge.
    Optional<Transaction> trans = transactions.stream().filter(t -> t.getTrader().getCity().equals("Cambridge")).findAny();
    System.out.println(trans);

    // Query 8: What's the lowest value in all the transactions?
    System.out.println(transactions.stream().map(Transaction::getValue).reduce(Integer::min));
    // Query 7: What's the highest value in all the transactions?
    System.out.println(transactions.stream().map(Transaction::getValue).reduce(Integer::max));

    // Query 8: What's the lowest value in all the transactions?
    System.out.println(transactions.stream().map(Transaction::getValue).reduce(Integer::min));
    }
    }
  3. iamlow revised this gist Mar 21, 2017. No changes.
  4. iamlow revised this gist Mar 21, 2017. 1 changed file with 17 additions and 17 deletions.
    34 changes: 17 additions & 17 deletions StreamAPI.java
    View file
    Original file line number Diff line number Diff line change
    @@ -1,42 +1,42 @@
    public class StreamAPI {
    public static void main(String ...args){
    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)
    );
    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)
    );

    // Query 1: Find all transactions from year 2011 and sort them by value (small to high).
    transactions.stream().filter(t -> t.getYear() == 2011).sorted(comparing(Transaction::getValue)).forEach(System.out::println);

    // Query 2: What are all the unique cities where the traders work?
    transactions.stream().map(t -> t.getTrader().getCity()).distinct().forEach(System.out::println);

    // Query 3: Find all traders from Cambridge and sort them by name.
    transactions.stream().map(Transaction::getTrader).filter(t -> t.getCity().equals("Cambridge")).distinct().sorted(comparing(Trader::getName)).forEach(System.out::println);

    // Query 4: Return a string of all traders’ names sorted alphabetically.
    System.out.println(transactions.stream().map(t -> t.getTrader().getName()).distinct().sorted().reduce("", (n1, n2) -> n1 + n2) + "\n");

    // Query 5: Are there any trader based in Milan?
    System.out.println(transactions.stream().anyMatch(t -> t.getTrader().getCity().equals("Milan")));

    // Query 6: Update all transactions so that the traders from Milan are set to Cambridge.
    Optional<Transaction> trans = transactions.stream().filter(t -> t.getTrader().getCity().equals("Cambridge")).findAny();
    System.out.println(trans);

    // Query 7: What's the highest value in all the transactions?
    System.out.println(transactions.stream().map(Transaction::getValue).reduce(Integer::max));

    // Query 8: What's the lowest value in all the transactions?
    System.out.println(transactions.stream().map(Transaction::getValue).reduce(Integer::min));
    }
    }
    }
  5. iamlow revised this gist Mar 21, 2017. No changes.
  6. iamlow revised this gist Mar 21, 2017. 1 changed file with 2 additions and 2 deletions.
    4 changes: 2 additions & 2 deletions StreamAPI.java
    View file
    Original file line number Diff line number Diff line change
    @@ -38,5 +38,5 @@ public static void main(String ...args){

    // Query 8: What's the lowest value in all the transactions?
    System.out.println(transactions.stream().map(Transaction::getValue).reduce(Integer::min));
    }
    }
    }
    }
  7. iamlow created this gist Mar 21, 2017.
    42 changes: 42 additions & 0 deletions StreamAPI.java
    View file
    Original file line number Diff line number Diff line change
    @@ -0,0 +1,42 @@
    public class StreamAPI {
    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)
    );

    // Query 1: Find all transactions from year 2011 and sort them by value (small to high).
    transactions.stream().filter(t -> t.getYear() == 2011).sorted(comparing(Transaction::getValue)).forEach(System.out::println);

    // Query 2: What are all the unique cities where the traders work?
    transactions.stream().map(t -> t.getTrader().getCity()).distinct().forEach(System.out::println);

    // Query 3: Find all traders from Cambridge and sort them by name.
    transactions.stream().map(Transaction::getTrader).filter(t -> t.getCity().equals("Cambridge")).distinct().sorted(comparing(Trader::getName)).forEach(System.out::println);

    // Query 4: Return a string of all traders’ names sorted alphabetically.
    System.out.println(transactions.stream().map(t -> t.getTrader().getName()).distinct().sorted().reduce("", (n1, n2) -> n1 + n2) + "\n");

    // Query 5: Are there any trader based in Milan?
    System.out.println(transactions.stream().anyMatch(t -> t.getTrader().getCity().equals("Milan")));

    // Query 6: Update all transactions so that the traders from Milan are set to Cambridge.
    Optional<Transaction> trans = transactions.stream().filter(t -> t.getTrader().getCity().equals("Cambridge")).findAny();
    System.out.println(trans);

    // Query 7: What's the highest value in all the transactions?
    System.out.println(transactions.stream().map(Transaction::getValue).reduce(Integer::max));

    // Query 8: What's the lowest value in all the transactions?
    System.out.println(transactions.stream().map(Transaction::getValue).reduce(Integer::min));
    }
    }