public abstract class AbstractMessageSource extends MessageSourceSupport implements HierarchicalMessageSource
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".
Supports not only MessageSourceResolvables as primary messages but also resolution of message arguments that are in turn MessageSourceResolvables themselves.
This class does not implement caching of messages per code, thus subclasses can dynamically change messages over time. Subclasses are encouraged to cache their messages in a modification-aware fashion, allowing for hot deployment of updated messages.
resolveCode(String, java.util.Locale)
,
resolveCodeWithoutArguments(String, java.util.Locale)
,
MessageSourceSupport.setAlwaysUseMessageFormat(boolean)
,
MessageFormat
Modifier and Type | Field and Description |
---|---|
private java.util.Properties |
commonMessages |
private MessageSource |
parentMessageSource |
private boolean |
useCodeAsDefaultMessage |
logger
Constructor and Description |
---|
AbstractMessageSource() |
Modifier and Type | Method and 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(MessageSourceResolvable resolvable,
java.util.Locale locale)
Try to resolve the message using all the attributes contained within the
MessageSourceResolvable argument that was passed in. |
java.lang.String |
getMessage(java.lang.String code,
java.lang.Object[] args,
java.util.Locale locale)
Try to resolve the message.
|
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.
|
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 java.lang.Object[] |
resolveArguments(java.lang.Object[] args,
java.util.Locale locale)
Searches through the given array of objects, finds any MessageSourceResolvable
objects and resolves them.
|
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.
|
createMessageFormat, formatMessage, isAlwaysUseMessageFormat, renderDefaultMessage, setAlwaysUseMessageFormat
private MessageSource parentMessageSource
private java.util.Properties commonMessages
private boolean useCodeAsDefaultMessage
public void setParentMessageSource(MessageSource parent)
HierarchicalMessageSource
setParentMessageSource
in interface HierarchicalMessageSource
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.public MessageSource getParentMessageSource()
HierarchicalMessageSource
null
if none.getParentMessageSource
in interface HierarchicalMessageSource
public void setCommonMessages(java.util.Properties commonMessages)
May also link to an externally defined Properties object, e.g. defined
through a PropertiesFactoryBean
.
protected java.util.Properties getCommonMessages()
public void setUseCodeAsDefaultMessage(boolean useCodeAsDefaultMessage)
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.
protected boolean isUseCodeAsDefaultMessage()
Alternatively, consider overriding the getDefaultMessage(java.lang.String)
method to return a custom fallback message for an unresolvable code.
getDefaultMessage(String)
public final java.lang.String getMessage(java.lang.String code, java.lang.Object[] args, java.lang.String defaultMessage, java.util.Locale locale)
MessageSource
getMessage
in interface MessageSource
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 failslocale
- the Locale in which to do the lookupMessageFormat
public final java.lang.String getMessage(java.lang.String code, java.lang.Object[] args, java.util.Locale locale) throws NoSuchMessageException
MessageSource
getMessage
in interface MessageSource
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 lookupNoSuchMessageException
- if the message wasn't foundMessageFormat
public final java.lang.String getMessage(MessageSourceResolvable resolvable, java.util.Locale locale) throws NoSuchMessageException
MessageSource
MessageSourceResolvable
argument that was passed in.
NOTE: We must throw a NoSuchMessageException
on this method
since at the time of calling this method we aren't able to determine if the
defaultMessage
property of the resolvable is null or not.
getMessage
in interface MessageSource
resolvable
- value object storing attributes required to properly resolve a messagelocale
- the Locale in which to do the lookupNoSuchMessageException
- if the message wasn't foundMessageFormat
protected java.lang.String getMessageInternal(java.lang.String code, java.lang.Object[] args, java.util.Locale locale)
null
if not found. Does not fall back to
the code as default message. Invoked by getMessage
methods.code
- the code to lookup up, such as 'calculator.noRateSet'args
- array of arguments that will be filled in for params
within the messagelocale
- the Locale in which to do the lookupnull
if not foundgetMessage(String, Object[], String, Locale)
,
getMessage(String, Object[], Locale)
,
getMessage(MessageSourceResolvable, Locale)
,
setUseCodeAsDefaultMessage(boolean)
protected java.lang.String getMessageFromParent(java.lang.String code, java.lang.Object[] args, java.util.Locale locale)
code
- the code to lookup up, such as 'calculator.noRateSet'args
- array of arguments that will be filled in for params
within the messagelocale
- the Locale in which to do the lookupnull
if not foundgetParentMessageSource()
protected java.lang.String getDefaultMessage(java.lang.String code)
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
.
code
- the message code that we couldn't resolve
and that we didn't receive an explicit default message fornull
if nonesetUseCodeAsDefaultMessage(boolean)
protected java.lang.Object[] resolveArguments(java.lang.Object[] args, java.util.Locale locale)
Allows for messages to have MessageSourceResolvables as arguments.
resolveArguments
in class MessageSourceSupport
args
- array of arguments for a messagelocale
- the locale to resolve throughprotected java.lang.String resolveCodeWithoutArguments(java.lang.String code, java.util.Locale locale)
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.
code
- the code of the message to resolvelocale
- the Locale to resolve the code for
(subclasses are encouraged to support internationalization)null
if not foundresolveCode(java.lang.String, java.util.Locale)
,
MessageFormat
protected abstract java.text.MessageFormat resolveCode(java.lang.String code, java.util.Locale locale)
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.
code
- the code of the message to resolvelocale
- the Locale to resolve the code for
(subclasses are encouraged to support internationalization)null
if not foundresolveCodeWithoutArguments(String, java.util.Locale)