Accessing Objects

Accessing Objects

The API of the JACIS store provides several methods to access the stored objects. Here is a list of the most important access methods:

TV get(K key);	Return the object for the passed key.
List<TV> getAll();	Return all objects in the store as a List.
List<TV> getAll(Predicate<TV> filter);	Return all objects matching the passed filter in the store as a List.
Stream<TV> stream();	Return all objects in the store as a stream.
Stream<TV> stream(Predicate<TV> filter);	Return all objects in the store matching the passed filter as a stream.
boolean containsKey(K key);	Check if the store contains an object.
int size();	Return the number of objects in the store.

To show some of the access methods in action we first we create some example objects to have some data to play around:

    container.withLocalTx(() -> {
      store.update("account0", new Account("account0").withdraw(100));
      store.update("account1", new Account("account1").deposit(100));
      store.update("account2", new Account("account2").deposit(200));
      store.update("account3", new Account("account3").deposit(300));
      store.update("account4", new Account("account4").deposit(400));
      store.update("account5", new Account("account5").deposit(500));
      store.update("account6", new Account("account6").deposit(600));
      store.update("account7", new Account("account7").deposit(700));
      store.update("account8", new Account("account8").deposit(800));
      store.update("account9", new Account("account9").deposit(900));
    });

Now we show some examples how to use the stream API:

    // Now we show some examples how to use the stream API:
    container.withLocalTx(() -> {

      // using stream methods (compute the total balance of all stored accounts):
      System.out.println("total balance=" + store.stream().mapToLong(Account::getBalance).sum());

      // using a filter (count accounts with a balance > 500):
      System.out.println("#>500=" + store.stream(acc -> acc.getBalance() > 500).count());

      // looping and updating (adding 10% interest to all accounts with a positive balance)
      store.stream(acc -> acc.getBalance() > 0).forEach(acc -> {
        store.update(acc.getName(), acc.deposit(acc.getBalance() / 10));
      });

      // output all accounts
      String str = store.stream().//
      sorted(Comparator.comparing(Account::getName)). //
      map(acc -> acc.getName() + ":" + acc.getBalance()).//
      collect(Collectors.joining(", "));
      System.out.println("Accounts: " + str);
    });