How to use play.i18n

/**
 * Constructs a MessagesApi instance containing the given keys and values.
 *
 * @return a messagesApi instance containing given keys and values.
 */
public static MessagesApi stubMessagesApi(Map<String, Map<String, String>> messages, play.i18n.Langs langs) {
  return new play.i18n.MessagesApi(
    new play.api.i18n.DefaultMessagesApi(messages, langs)
  );
}

/**
* Translates a message.
*
* Uses `java.text.MessageFormat` internally to format the message.
*
* @param key the message key
* @param args the message arguments
* @return the formatted message or a default rendering if the key wasn't defined
*/
public static String get(String key, Object... args) {
  return getMessagesApi().get(getLang(), key, args);
}

/**
* Check if a message key is defined.
* @param lang the message lang
* @param key the message key
* @return a Boolean
*/
public static Boolean isDefined(Lang lang, String key) {
  return getMessagesApi().isDefinedAt(lang, key);
}

/**
 * Get the message at the given key.
 *
 * Uses `java.text.MessageFormat` internally to format the message.
 *
 * @param key the message key
 * @param args the message arguments
 * @return the formatted message or a default rendering if the key wasn't defined
 */
public String at(String key, Object... args) {
  return messages.get(lang, key, args);
}

/**
 * Get the message at the given key.
 *
 * Uses `java.text.MessageFormat` internally to format the message.
 *
 * @param key the message key
 * @param args the message arguments
 * @return the formatted message or a default rendering if the key wasn't defined
 */
default String apply(String key, Object... args) {
  return at(key, args);
}

/**
* Translates a message.
*
* Uses `java.text.MessageFormat` internally to format the message.
*
* @param lang the message lang
* @param key the message key
* @param args the message arguments
* @return the formatted message or a default rendering if the key wasn't defined
*/
public static String get(Lang lang, String key, Object... args) {
  return getMessagesApi().get(lang, key, args);
}

/**
* Check if a message key is defined.
* @param key the message key
* @return a Boolean
*/
public static Boolean isDefined(String key) {
  return getMessagesApi().isDefinedAt(getLang(), key);
}

/**
 * Check if a message key is defined.
 *
 * @param key the message key
 * @return a Boolean
 */
public Boolean isDefinedAt(String key) {
  return messagesApi.isDefinedAt(lang, key);
}

/**
 * Convert to a Java Locale value.
 */
public java.util.Locale toLocale() {
  return locale();
}

/**
 * Get the message at the given key.
 *
 * Uses `java.text.MessageFormat` internally to format the message.
 *
 * @param key the message key
 * @param args the message arguments
 * @return the formatted message or a default rendering if the key wasn't defined
 */
public String at(String key, Object... args) {
  return messagesApi.get(lang, key, args);
}

/**
* Translates the first defined message.
*
* Uses `java.text.MessageFormat` internally to format the message.
*
* @param keys the messages keys
* @param args the message arguments
* @return the formatted message or a default rendering if the key wasn't defined
*/
public static String get(List<String> keys, Object... args) {
  return getMessagesApi().get(getLang(), keys, args);
}

/**
 * Get the message at the first defined key.
 *
 * Uses `java.text.MessageFormat` internally to format the message.
 *
 * @param keys the messages keys
 * @param args the message arguments
 * @return the formatted message or a default rendering if the key wasn't defined
 */
default String apply(List<String> keys, Object... args) {
  return at(keys, args);
}

/**
* Translates the first defined message.
*
* Uses `java.text.MessageFormat` internally to format the message.
*
* @param lang the message lang
* @param keys the messages keys
* @param args the message arguments
* @return the formatted message or a default rendering if the key wasn't defined
*/
public static String get(Lang lang, List<String> keys, Object... args) {
  return getMessagesApi().get(lang, keys, args);
}

/**
 * Check if a message key is defined.
 *
 * @param key the message key
 * @return a Boolean
 */
public Boolean isDefinedAt(String key) {
  return messagesApi.isDefinedAt(lang, key);
}

/**
 * Constructs a MessagesApi instance containing the given keys and values.
 *
 * @return a messagesApi instance containing given keys and values.
 */
public static MessagesApi stubMessagesApi(Map<String, Map<String, String>> messages, play.i18n.Langs langs) {
  return new play.i18n.MessagesApi(
    new play.api.i18n.DefaultMessagesApi(messages, langs)
  );
}

/**
 * Get the message at the first defined key.
 *
 * Uses `java.text.MessageFormat` internally to format the message.
 *
 * @param keys the messages keys
 * @param args the message arguments
 * @return the formatted message or a default rendering if the key wasn't defined
 */
public String at(List<String> keys, Object... args) {
  return messagesApi.get(lang, keys, args);
}

/**
 * Get the message at the given key.
 *
 * Uses `java.text.MessageFormat` internally to format the message.
 *
 * @param key the message key
 * @param args the message arguments
 * @return the formatted message or a default rendering if the key wasn't defined
 */
default String apply(String key, Object... args) {
  return at(key, args);
}

/**
 * Constructs an empty messagesApi instance.
 *
 * @return a messagesApi instance containing no values.
 */
public static MessagesApi stubMessagesApi() {
  return new play.i18n.MessagesApi(new play.api.i18n.DefaultMessagesApi
      (Collections.emptyMap(), new DefaultLangs().asJava()));
}

/**
 * Get the message at the first defined key.
 *
 * Uses `java.text.MessageFormat` internally to format the message.
 *
 * @param keys the messages keys
 * @param args the message arguments
 * @return the formatted message or a default rendering if the key wasn't defined
 */
public String at(List<String> keys, Object... args) {
  return messagesApi.get(lang, keys, args);
}

/**
 * Constructs an empty messagesApi instance.
 *
 * @return a messagesApi instance containing no values.
 */
public static MessagesApi stubMessagesApi() {
  return new play.i18n.MessagesApi(new play.api.i18n.DefaultMessagesApi
      (Collections.emptyMap(), new DefaultLangs().asJava()));
}