Package com.aspectran.core.support.i18n.message

Class AbstractMessageSource

java.lang.Object

com.aspectran.core.support.i18n.message.MessageSourceSupport

com.aspectran.core.support.i18n.message.AbstractMessageSource

All Implemented Interfaces:

HierarchicalMessageSource, MessageSource

Direct Known Subclasses:

ResourceBundleMessageSource

public abstract class AbstractMessageSource
extends MessageSourceSupport
implements HierarchicalMessageSource

Abstract implementation of the HierarchicalMessageSource interface, implementing common handling of message variants, making it easy to implement a specific strategy for a concrete MessageSource.

Subclasses must implement the abstract resolveCode(java.lang.String, java.util.Locale) method. For efficient resolution of messages without arguments, the resolveCodeWithoutArguments(java.lang.String, java.util.Locale) method should be overridden as well, resolving messages without a MessageFormat being involved.

Note: By default, message texts are only parsed through MessageFormat if arguments have been passed in for the message. In case of no arguments, message texts will be returned as-is. As a consequence, you should only use MessageFormat escaping for messages with actual arguments, and keep all other messages unescaped. If you prefer to escape all messages, set the "alwaysUseMessageFormat" flag to "true".

Created: 2016. 2. 8.

Field Summary

Fields inherited from class com.aspectran.core.support.i18n.message.MessageSourceSupport

log

Constructor Summary

Constructors

Constructor	Description
AbstractMessageSource()

Method Summary

Modifier and Type	Method	Description
protected java.util.Properties	getCommonMessages()	Return a Properties object defining locale-independent common messages, if any.
protected java.lang.String	getDefaultMessage(java.lang.String code)	Return a fallback default message for the given code, if any.
java.lang.String	getMessage(java.lang.String code, java.lang.Object[] args, java.lang.String defaultMessage, java.util.Locale locale)	Try to resolve the message.
java.lang.String	getMessage(java.lang.String code, java.lang.Object[] args, java.util.Locale locale)	Try to resolve the message.
protected java.lang.String	getMessageFromParent(java.lang.String code, java.lang.Object[] args, java.util.Locale locale)	Try to retrieve the given message from the parent MessageSource, if any.
protected java.lang.String	getMessageInternal(java.lang.String code, java.lang.Object[] args, java.util.Locale locale)	Resolve the given code and arguments as message in the given Locale, returning null if not found.
MessageSource	getParentMessageSource()	Return the parent of this MessageSource, or null if none.
protected boolean	isUseCodeAsDefaultMessage()	Return whether to use the message code as default message instead of throwing a NoSuchMessageException.
protected abstract java.text.MessageFormat	resolveCode(java.lang.String code, java.util.Locale locale)	Subclasses must implement this method to resolve a message.
protected java.lang.String	resolveCodeWithoutArguments(java.lang.String code, java.util.Locale locale)	Subclasses can override this method to resolve a message without arguments in an optimized fashion, i.e.
void	setCommonMessages(java.util.Properties commonMessages)	Specify locale-independent common messages, with the message code as key and the full message String (may contain argument placeholders) as value.
void	setParentMessageSource(MessageSource parent)	Set the parent that will be used to try to resolve messages that this object can't resolve.
void	setUseCodeAsDefaultMessage(boolean useCodeAsDefaultMessage)	Set whether to use the message code as default message instead of throwing a NoSuchMessageException.

Methods inherited from class com.aspectran.core.support.i18n.message.MessageSourceSupport

createMessageFormat, formatMessage, isAlwaysUseMessageFormat, renderDefaultMessage, resolveArguments, setAlwaysUseMessageFormat

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

AbstractMessageSource

public AbstractMessageSource()

Method Detail

setParentMessageSource

public void setParentMessageSource(MessageSource parent)

Description copied from interface: HierarchicalMessageSource

Set the parent that will be used to try to resolve messages that this object can't resolve.

Specified by:

setParentMessageSource in interface HierarchicalMessageSource

Parameters:

parent - the parent MessageSource that will be used to resolve messages that this object can't resolve. May be null, in which case no further resolution is possible.

getParentMessageSource

public MessageSource getParentMessageSource()

Description copied from interface: HierarchicalMessageSource

Return the parent of this MessageSource, or null if none.

Specified by:

getParentMessageSource in interface HierarchicalMessageSource

Returns:

the parent message source

setCommonMessages

public void setCommonMessages(java.util.Properties commonMessages)

Specify locale-independent common messages, with the message code as key and the full message String (may contain argument placeholders) as value.

Parameters:

commonMessages - the common messages

getCommonMessages

protected java.util.Properties getCommonMessages()

Return a Properties object defining locale-independent common messages, if any.

Returns:

the common messages

setUseCodeAsDefaultMessage

public void setUseCodeAsDefaultMessage(boolean useCodeAsDefaultMessage)

Set whether to use the message code as default message instead of throwing a NoSuchMessageException. Useful for development and debugging. Default is "false".

Note: In case of a MessageSourceResolvable with multiple codes (like a FieldError) and a MessageSource that has a parent MessageSource, do not activate "useCodeAsDefaultMessage" in the parent: Else, you'll get the first code returned as message by the parent, without attempts to check further codes.

To be able to work with "useCodeAsDefaultMessage" turned on in the parent, AbstractMessageSource and AbstractApplicationContext contain special checks to delegate to the internal getMessageInternal(java.lang.String, java.lang.Object[], java.util.Locale) method if available. In general, it is recommended to just use "useCodeAsDefaultMessage" during development and not rely on it in production in the first place, though.

Parameters:

useCodeAsDefaultMessage - whether use code as default message

See Also:

#getMessage(String, Object[], Locale)

isUseCodeAsDefaultMessage

protected boolean isUseCodeAsDefaultMessage()

Return whether to use the message code as default message instead of throwing a NoSuchMessageException. Useful for development and debugging. Default is "false".

Alternatively, consider overriding the getDefaultMessage(java.lang.String) method to return a custom fallback message for an unresolvable code.

Returns:

whether use code as default message

See Also:

#getDefaultMessage(String)

getMessage

public final java.lang.String getMessage(java.lang.String code,
                                         java.lang.Object[] args,
                                         java.lang.String defaultMessage,
                                         java.util.Locale locale)

Description copied from interface: MessageSource

Try to resolve the message. Return default message if no message was found.

Specified by:

getMessage in interface MessageSource

Parameters:

code - the code to lookup up, such as 'calculator.noRateSet'. Users of this class are encouraged to base message names on the relevant fully qualified class name, thus avoiding conflict and ensuring maximum clarity.

args - array of arguments that will be filled in for params within the message (params look like "{0}", "{1,date}", "{2,time}" within a message), or null if none.

defaultMessage - String to return if the lookup fails

locale - the Locale in which to do the lookup

Returns:

the resolved message if the lookup was successful; otherwise the default message passed as a parameter

See Also:

MessageFormat

getMessage

public final java.lang.String getMessage(java.lang.String code,
                                         java.lang.Object[] args,
                                         java.util.Locale locale)
                                  throws NoSuchMessageException

Description copied from interface: MessageSource

Try to resolve the message. Treat as an error if the message can't be found.

Specified by:

getMessage in interface MessageSource

Parameters:

code - the code to lookup up, such as 'calculator.noRateSet'

args - Array of arguments that will be filled in for params within the message (params look like "{0}", "{1,date}", "{2,time}" within a message), or null if none.

locale - the Locale in which to do the lookup

Returns:

the resolved message

Throws:

NoSuchMessageException - if the message wasn't found

See Also:

MessageFormat

getMessageInternal

protected java.lang.String getMessageInternal(java.lang.String code,
                                              java.lang.Object[] args,
                                              java.util.Locale locale)

Resolve the given code and arguments as message in the given Locale, returning null if not found. Does not fall back to the code as default message. Invoked by getMessage methods.

Parameters:

code - the code to lookup up, such as 'calculator.noRateSet'

args - array of arguments that will be filled in for params within the message

locale - the Locale in which to do the lookup

Returns:

the resolved message, or null if not found

See Also:

#getMessage(String, Object[], String, Locale), #getMessage(String, Object[], Locale), #setUseCodeAsDefaultMessage

getMessageFromParent

protected java.lang.String getMessageFromParent(java.lang.String code,
                                                java.lang.Object[] args,
                                                java.util.Locale locale)

Try to retrieve the given message from the parent MessageSource, if any.

Parameters:

code - the code to lookup up, such as 'calculator.noRateSet'

args - array of arguments that will be filled in for params within the message

locale - the Locale in which to do the lookup

Returns:

the resolved message, or null if not found

See Also:

#getParentMessageSource()

getDefaultMessage

protected java.lang.String getDefaultMessage(java.lang.String code)

Return a fallback default message for the given code, if any.

Default is to return the code itself if "useCodeAsDefaultMessage" is activated, or return no fallback else. In case of no fallback, the caller will usually receive a NoSuchMessageException from getMessage.

Parameters:

code - the message code that we couldn't resolve and that we didn't receive an explicit default message for

Returns:

the default message to use, or null if none

See Also:

#setUseCodeAsDefaultMessage

resolveCodeWithoutArguments

protected java.lang.String resolveCodeWithoutArguments(java.lang.String code,
                                                       java.util.Locale locale)

Subclasses can override this method to resolve a message without arguments in an optimized fashion, i.e. to resolve without involving a MessageFormat.

The default implementation does use MessageFormat, through delegating to the resolveCode(java.lang.String, java.util.Locale) method. Subclasses are encouraged to replace this with optimized resolution.

Unfortunately, java.text.MessageFormat is not implemented in an efficient fashion. In particular, it does not detect that a message pattern doesn't contain argument placeholders in the first place. Therefore, it is advisable to circumvent MessageFormat for messages without arguments.

Parameters:

code - the code of the message to resolve

locale - the Locale to resolve the code for (subclasses are encouraged to support internationalization)

Returns:

the message String, or null if not found

See Also:

#resolveCode, MessageFormat

resolveCode

protected abstract java.text.MessageFormat resolveCode(java.lang.String code,
                                                       java.util.Locale locale)

Subclasses must implement this method to resolve a message.

Returns a MessageFormat instance rather than a message String, to allow for appropriate caching of MessageFormats in subclasses.

Subclasses are encouraged to provide optimized resolution for messages without arguments, not involving MessageFormat. See the resolveCodeWithoutArguments(java.lang.String, java.util.Locale) javadoc for details.

Parameters:

code - the code of the message to resolve

locale - the Locale to resolve the code for (subclasses are encouraged to support internationalization)

Returns:

the MessageFormat for the message, or null if not found

See Also:

#resolveCodeWithoutArguments(String, java.util.Locale)