Composing complex strings

Perform this task to insert variable substrings into a localized string.

Identify strings that need to be localized.

The localized-text package supports the substitution of variable substrings into a localized string that is retrieved from the message catalog by key.

1. In the message catalog, specify the location of the substitution in the string to be retrieved. Variable components are designated by braces (for example, {0}).

2. In application code, create a LocalizableTextFormatter instance, passing in an array containing the variable value. If the variable substring must be localized, we can create a nested LocalizableTextFormatter instance and pass the instance in instead of a value.

3. Generate a localized string.
   When a format method is called on a formatter instance, the formatter takes each element of the array passed in the previous step and substitutes it for the placeholder with the matching index in the string that is retrieved from the message catalog. For example, the value at index 0 in the array replaces the {0} variable in the retrieved string.

Example

The following line from an English message catalog shows a string with a single substitution:

successfulTransaction = The operation on account {0} was successful.

The same key in message catalogs for other languages has a translation of this string with the variable at the appropriate location for each language.

The following code shows the creation of a single-element argument array and the creation and use of a LocalizableTextFormatter instance:

public void updateAccount(String transactionType) {
   ...
   Object[] arg = {new String(this.accountNumber)};
   ...
   LocalizableTextFormatter successLTF =
      new LocalizableTextFormatter ("BankingResources", "successfulTransaction", "BankingSample", arg);
   ...
   successLTF.format(this.applicationLocale);
   ...
}

Subtopics

• Nesting formatter instances for localized substrings
  The ability to substitute variable substrings into the strings retrieved from message catalogs adds a level of flexibility to the localizable-text package, but this capability is of limited use unless the variable value can be localized. We can localize this value by nesting LocalizableTextFormatter instances.

Related tasks

Set optional localization values

LocalizableTextFormatter class