# Class yii\i18n\MessageSource

Inheritance | yii\i18n\MessageSource » yii\base\Component » yii\base\BaseObject
Implements | yii\base\Configurable
Subclasses | yii\i18n\DbMessageSource, yii\i18n\GettextMessageSource, yii\i18n\PhpMessageSource, yii\mongodb\i18n\MongoDbMessageSource
Available since version | 2.0
Source Code | https://github.com/yiisoft/yii2/blob/master/framework/i18n/MessageSource.php

MessageSource is the base class for message translation repository classes.

A message source stores message translations in some persistent storage.

Child classes should override loadMessages() to provide translated messages.

## Public Properties

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Property | Type | Description | Defined By
--- | --- | --- | ---
$behaviors | yii\base\Behavior[] | List of behaviors attached to this component. This property is read-only. | yii\base\Component
$forceTranslation | boolean | Whether to force message translation when the source and target languages are the same. | yii\i18n\MessageSource
$sourceLanguage | string | The language that the original messages are in. | yii\i18n\MessageSource

## Public Methods

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Method | Description | Defined By
--- | --- | ---
__call() | Calls the named method which is not a class method. | yii\base\Component
__clone() | This method is called after the object is created by cloning an existing one. | yii\base\Component
__construct() | Constructor. | yii\base\BaseObject
__get() | Returns the value of a component property. | yii\base\Component
__isset() | Checks if a property is set, i.e. defined and not null. | yii\base\Component
__set() | Sets the value of a component property. | yii\base\Component
__unset() | Sets a component property to be null. | yii\base\Component
attachBehavior() | Attaches a behavior to this component. | yii\base\Component
attachBehaviors() | Attaches a list of behaviors to the component. | yii\base\Component
behaviors() | Returns a list of behaviors that this component should behave as. | yii\base\Component
canGetProperty() | Returns a value indicating whether a property can be read. | yii\base\Component
canSetProperty() | Returns a value indicating whether a property can be set. | yii\base\Component
className() | Returns the fully qualified name of this class. | yii\base\BaseObject
detachBehavior() | Detaches a behavior from the component. | yii\base\Component
detachBehaviors() | Detaches all behaviors from the component. | yii\base\Component
ensureBehaviors() | Makes sure that the behaviors declared in behaviors() are attached to this component. | yii\base\Component
getBehavior() | Returns the named behavior object. | yii\base\Component
getBehaviors() | Returns all behaviors attached to this component. | yii\base\Component
hasEventHandlers() | Returns a value indicating whether there is any handler attached to the named event. | yii\base\Component
hasMethod() | Returns a value indicating whether a method is defined. | yii\base\Component
hasProperty() | Returns a value indicating whether a property is defined for this component. | yii\base\Component
init() | Initializes this component. | yii\i18n\MessageSource
off() | Detaches an existing event handler from this component. | yii\base\Component
on() | Attaches an event handler to an event. | yii\base\Component
translate() | Translates a message to the specified language. | yii\i18n\MessageSource
trigger() | Triggers an event. | yii\base\Component

## Protected Methods

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Method | Description | Defined By
--- | --- | ---
loadMessages() | Loads the message translation for the specified language and category. | yii\i18n\MessageSource
translateMessage() | Translates the specified message. | yii\i18n\MessageSource

## Events

Hide inherited events

Event | Type | Description | Defined By
--- | --- | --- | ---
EVENT_MISSING_TRANSLATION | yii\i18n\MissingTranslationEvent | An event that is triggered when a message translation is not found. | yii\i18n\MessageSource

## Property Details

$forceTranslation public property

Whether to force message translation when the source and target languages are the same. Defaults to false, meaning translation is only performed when source and target languages are different.

public boolean $forceTranslation = false
$sourceLanguage public property

The language that the original messages are in. If not set, it will use the value of yii\base\Application::$sourceLanguage.

public string $sourceLanguage = null

## Method Details

init() public method

Initializes this component.

public void init ( )

loadMessages() protected method

Loads the message translation for the specified language and category.

If translation for specific locale code such as `en-US` isn't found it tries more generic `en`.

protected array loadMessages ( $category, $language )
$category | string | The message category
$language | string | The target language
return | array | The loaded messages. The keys are original messages, and the values are translated messages.

translate() public method

Translates a message to the specified language.

Note that unless $forceTranslation is true, if the target language is the same as the source language, the message will NOT be translated.

If a translation is not found, a missingTranslation event will be triggered.

public string|boolean translate ( $category, $message, $language )
$category | string | The message category
$message | string | The message to be translated
$language | string | The target language
return | string|boolean | The translated message or false if translation wasn't found or isn't required

translateMessage() protected method

Translates the specified message.

If the message is not found, a missingTranslation event will be triggered. If there is an event handler, it may provide a fallback translation. If no fallback translation is provided this method will return `false`.

protected string|boolean translateMessage ( $category, $message, $language )
$category | string | The category that the message belongs to.
$message | string | The message to be translated.
$language | string | The target language.
return | string|boolean | The translated message or false if translation wasn't found.

## Event Details

EVENT_MISSING_TRANSLATION event of type yii\i18n\MissingTranslationEvent

An event that is triggered when a message translation is not found.