JAVA myString['name'] = "my value"; (like in Php)

Question

In Php I really often use this one:

$conn_sets = array();
$conn_sets['login'] = "aaa";
$conn_sets['pass'] = "bbb";

How to do the same in JAVA 1.6. I tried to do this:

private method1() {    
    String[] mystring = new String[] {"login" => "aaa", "pass" => "bbb"};
}

But it give's me an error. I want to make this work, because I have an error lists declarations, and it is better to identify:

throw new MyException(myerrors['failed_login_error']);

than a:

throw new MyException(myerrors[116]);

I know I can do a new class, and throw an object:

throw new MyException(ERROR_CONSTANTS.FAILED_LOGIN_ERROR);

But I prefer the first one (the same as I use in Php).

So, any ideas?

Answer 1

In Java, you probably want to use the Map interface, such as a HashMap.

Although, I would say that using an Enum is actually what you should be doing in your second (list of errors) example. Forget about PHP when you're in Java. Enums are much better in this case because you want a well-defined list of keys.

Answer 2

You could use the double brace pattern:

Map<String, String> map = new HashMap<String, String>() {{
    put( "login", "aaa" );
    put( "pass", "bbb" );
}};

... and your other example:

throw new MyException( myErrors.get( "failed_login_error" ) );

Answer 3

You really should be using Properties (or better yet a ResourceBundle to abstract the properties file) for this particular case.

Here is a tutorial on the usage.

This is a much better way as you can internationalize (I18N) the messages (if you want) and you can specify them in text files rather than inside the code (messages are much better in text than in code so you can update them without having to rebuild).

Answer 4

You don't want to use a HashMap or a Properties object to store wildly named parameters. You really want to think object-oriented and use a class to encapsulate the data of an account and to express what an object really represents in the real world:

String username = "aaa";
String password = "bbb";
Account acc = new Account(username,password);
if (!tryLogin(acc)) {
 throw new LoginFailedException(account);
}

That way, clients who catch the LoginFailedException can make use of the information and use statically typed methods with good names to, for example, retrieve the username by calling loginFailedException.getUsername().