# Simple OAuth2 with Password and Bearer { #simple-oauth2-with-password-and-bearer }

Now let's build from the previous chapter and add the missing parts to have a complete security flow.

## Get the `username` and `password` { #get-the-username-and-password }

We are going to use **FastAPI** security utilities to get the `username` and `password`.

    Iterable<String> letters = Splitter.fixedLength(1).limit(100).split(simple);
    assertThat(letters).containsExactly("a", "b", "c", "d").inOrder();
  }

  public void testLimitOne() {
    String simple = "abcd";
    Iterable<String> letters = Splitter.fixedLength(1).limit(1).split(simple);
    assertThat(letters).containsExactly("abcd").inOrder();
  }

  public void testLimitFixedLength() {

		parities []int
		parity   int
	}{
		// More than simple majority consensus
		mkTest(15, 3, 11),
		// No simple majority consensus
		mkTest(15, 3, 7),
		// Exact simple majority consensus
		mkTest(15, 3, 8),
		// More than simple majority consensus
		mkTest(16, 4, 11),
		// No simple majority consensus
		mkTest(16, 4, 8),
		// Exact simple majority consensus
		mkTest(16, 4, 9),

        return args;
    }

    @Override
    public String getMessage() {
        return message;
    }

    /**
     * Returns a simple message without a message code.
     *
     * @return simple message without message code
     */
    public final String getSimpleMessage() {
        return simpleMessage;
    }

* external APIs
* authentication and authorization systems
* API usage monitoring systems
* response data injection systems
* etc.

## Simple and Powerful { #simple-and-powerful }

Although the hierarchical dependency injection system is very simple to define and use, it's still very powerful.

You can define dependencies that in turn can define dependencies themselves.

        String value;
        String[] result;

        // Single unquoted value
        value = "single";
        result = KuromojiCSVUtil.parse(value);
        assertEquals(1, result.length);
        assertEquals("single", result[0]);

        // Single quoted value - quotes preserved
        value = "\"single quoted\"";
        result = KuromojiCSVUtil.parse(value);

Apart from all the fancy words used here, the **Dependency Injection** system is quite simple.

Just functions that look the same as the *path operation functions*.

But still, it is very powerful, and allows you to declare arbitrarily deeply nested dependency "graphs" (trees).

/// tip

All this might not seem as useful with these simple examples.

But you will see how useful it is in the chapters about **security**.

     * @param simpleMessage
     *            Simple message with arguments expanded
     * @return Message with message code
     */
    public static String getFormattedMessage(final String messageCode, final String simpleMessage) {
        return "[" + messageCode + "]" + simpleMessage;
    }

    /**
     * Expands arguments and returns a simple message without a message code.
     *
     * @param messageCode

    private static final Logger logger = LogManager.getLogger(DataStoreFactory.class);

    /**
     * Map containing registered data store instances indexed by their names and class simple names.
     * All keys are stored in lowercase for case-insensitive lookup.
     */
    protected Map<String, DataStore> dataStoreMap = new LinkedHashMap<>();

    /**

```
Client #1596980209979 left the chat
```

/// tip

The app above is a minimal and simple example to demonstrate how to handle and broadcast messages to several WebSocket connections.

But keep in mind that, as everything is handled in memory, in a single list, it will only work while the process is running, and will only work with a single process.