Package org.springframework.web.servlet.tags

Class MessageTag

java.lang.Object

jakarta.servlet.jsp.tagext.TagSupport

org.springframework.web.servlet.tags.RequestContextAwareTag

org.springframework.web.servlet.tags.HtmlEscapingAwareTag

org.springframework.web.servlet.tags.MessageTag

All Implemented Interfaces:

IterationTag, JspTag, Tag, TryCatchFinally, Serializable, ArgumentAware

Direct Known Subclasses:

ThemeTag

public class MessageTag
extends HtmlEscapingAwareTag
implements ArgumentAware

The <message> tag looks up a message in the scope of this page. Messages are resolved using the ApplicationContext and thus support internationalization.

Detects an HTML escaping setting, either on this tag instance, the page level, or the web.xml level. Can also apply JavaScript escaping.

If "code" isn't set or cannot be resolved, "text" will be used as default message. Thus, this tag can also be used for HTML escaping of any texts.

Message arguments can be specified via the arguments attribute or by using nested <spring:argument> tags.

Attribute Summary

Attribute	Required?	Runtime Expression?	Description
arguments	false	true	Set optional message arguments for this tag, as a (comma-)delimited String (each String argument can contain JSP EL), an Object array (used as argument array), or a single Object (used as single argument).
argumentSeparator	false	true	The separator character to be used for splitting the arguments string value; defaults to a 'comma' (',').
code	false	true	The code (key) to use when looking up the message. If code is not provided, the text attribute will be used.
htmlEscape	false	true	Set HTML escaping for this tag, as boolean value. Overrides the default HTML escaping setting for the current page.
javaScriptEscape	false	true	Set JavaScript escaping for this tag, as boolean value. Default is false.
message	false	true	A MessageSourceResolvable argument (direct or through JSP EL). Fits nicely when used in conjunction with Spring’s own validation error classes which all implement the MessageSourceResolvable interface. For example, this allows you to iterate over all of the errors in a form, passing each error (using a runtime expression) as the value of this 'message' attribute, thus effecting the easy display of such error messages.
scope	false	true	The scope to use when exporting the result to a variable. This attribute is only used when var is also set. Possible values are page, request, session and application.
text	false	true	Default text to output when a message for the given code could not be found. If both text and code are not set, the tag will output null.
var	false	true	The string to use when binding the result to the page, request, session or application scope. If not specified, the result gets outputted to the writer (i.e. typically directly to the JSP).

Author:

Rod Johnson, Juergen Hoeller, Nicholas Williams

See Also:

• setCode(java.lang.String)
• setText(java.lang.String)
• HtmlEscapingAwareTag.setHtmlEscape(boolean)
• setJavaScriptEscape(boolean)
• HtmlEscapeTag.setDefaultHtmlEscape(boolean)
• WebUtils.HTML_ESCAPE_CONTEXT_PARAM
• ArgumentTag
• Serialized Form

Field Summary

Fields

Modifier and Type	Field	Description
static final String	DEFAULT_ARGUMENT_SEPARATOR	Default separator for splitting an arguments String: a comma (",").

Fields inherited from class org.springframework.web.servlet.tags.RequestContextAwareTag

logger, REQUEST_CONTEXT_PAGE_ATTRIBUTE

Fields inherited from class jakarta.servlet.jsp.tagext.TagSupport

id, pageContext

Fields inherited from interface jakarta.servlet.jsp.tagext.IterationTag

EVAL_BODY_AGAIN

Fields inherited from interface jakarta.servlet.jsp.tagext.Tag

EVAL_BODY_INCLUDE, EVAL_PAGE, SKIP_BODY, SKIP_PAGE

Constructor Summary

Constructors

Constructor	Description
MessageTag()

Method Summary

Modifier and Type	Method	Description
void	addArgument(Object argument)	Callback hook for nested spring:argument tags to pass their value to the parent tag.
int	doEndTag()	Resolves the message, escapes it if demanded, and writes it to the page (or exposes it as variable).
protected final int	doStartTagInternal()	Called by doStartTag to perform the actual work.
protected MessageSource	getMessageSource()	Use the current RequestContext's application context as MessageSource.
protected String	getNoSuchMessageExceptionDescription(NoSuchMessageException ex)	Return default exception message.
void	release()
protected Object[]	resolveArguments(Object arguments)	Resolve the given arguments Object into an arguments array.
protected String	resolveMessage()	Resolve the specified message into a concrete message String.
void	setArguments(Object arguments)	Set optional message arguments for this tag, as a comma-delimited String (each String argument can contain JSP EL), an Object array (used as argument array), or a single Object (used as single argument).
void	setArgumentSeparator(String argumentSeparator)	Set the separator to use for splitting an arguments String.
void	setCode(String code)	Set the message code for this tag.
void	setJavaScriptEscape(boolean javaScriptEscape)	Set JavaScript escaping for this tag, as boolean value.
void	setMessage(MessageSourceResolvable message)	Set the MessageSourceResolvable for this tag.
void	setScope(String scope)	Set the scope to export the variable to.
void	setText(String text)	Set the message text for this tag.
void	setVar(String var)	Set PageContext attribute name under which to expose a variable that contains the resolved message.
protected void	writeMessage(String msg)	Write the message to the page.

Methods inherited from class org.springframework.web.servlet.tags.HtmlEscapingAwareTag

htmlEscape, isDefaultHtmlEscape, isHtmlEscape, isResponseEncodedHtmlEscape, setHtmlEscape

Methods inherited from class org.springframework.web.servlet.tags.RequestContextAwareTag

doCatch, doFinally, doStartTag, getRequestContext

Methods inherited from class jakarta.servlet.jsp.tagext.TagSupport

doAfterBody, findAncestorWithClass, getId, getParent, getValue, getValues, removeValue, setId, setPageContext, setParent, setValue

Methods inherited from class java.lang.Object

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

Field Details

DEFAULT_ARGUMENT_SEPARATOR

public static final String DEFAULT_ARGUMENT_SEPARATOR

Default separator for splitting an arguments String: a comma (",").

See Also:

• Constant Field Values

Constructor Details

MessageTag

public MessageTag()

Method Details

setMessage

public void setMessage(MessageSourceResolvable message)

Set the MessageSourceResolvable for this tag.

If a MessageSourceResolvable is specified, it effectively overrides any code, arguments or text specified on this tag.

setCode

public void setCode(String code)

Set the message code for this tag.

setArguments

public void setArguments(Object arguments)

Set optional message arguments for this tag, as a comma-delimited String (each String argument can contain JSP EL), an Object array (used as argument array), or a single Object (used as single argument).

setArgumentSeparator

public void setArgumentSeparator(String argumentSeparator)

Set the separator to use for splitting an arguments String. Default is a comma (",").

See Also:

• setArguments(java.lang.Object)

addArgument

public void addArgument(@Nullable
 Object argument)
                 throws JspTagException

Description copied from interface: ArgumentAware

Callback hook for nested spring:argument tags to pass their value to the parent tag.

Specified by:

addArgument in interface ArgumentAware

Parameters:

argument - the result of the nested spring:argument tag

Throws:

JspTagException

setText

public void setText(String text)

Set the message text for this tag.

setVar

public void setVar(String var)

Set PageContext attribute name under which to expose a variable that contains the resolved message.

See Also:

• setScope(java.lang.String)
• JspContext.setAttribute(java.lang.String, java.lang.Object)

setScope

public void setScope(String scope)

Set the scope to export the variable to. Default is SCOPE_PAGE ("page").

See Also:

• setVar(java.lang.String)
• TagUtils.SCOPE_PAGE
• JspContext.setAttribute(java.lang.String, java.lang.Object)

setJavaScriptEscape

public void setJavaScriptEscape(boolean javaScriptEscape)
                         throws JspException

Set JavaScript escaping for this tag, as boolean value. Default is "false".

Throws:

JspException

doStartTagInternal

protected final int doStartTagInternal()
                                throws JspException,
IOException

Description copied from class: RequestContextAwareTag

Called by doStartTag to perform the actual work.

Specified by:

doStartTagInternal in class RequestContextAwareTag

Returns:

same as TagSupport.doStartTag

Throws:

JspException

IOException

See Also:

• TagSupport.doStartTag()

doEndTag

public int doEndTag()
             throws JspException

Resolves the message, escapes it if demanded, and writes it to the page (or exposes it as variable).

Specified by:

doEndTag in interface Tag

Overrides:

doEndTag in class TagSupport

Throws:

JspException

See Also:

• resolveMessage()
• HtmlUtils.htmlEscape(String)
• JavaScriptUtils.javaScriptEscape(String)
• writeMessage(String)

release

public void release()

Specified by:

release in interface Tag

Overrides:

release in class TagSupport

resolveMessage

protected String resolveMessage()
                         throws JspException,
NoSuchMessageException

Resolve the specified message into a concrete message String. The returned message String should be unescaped.

Throws:

JspException

NoSuchMessageException

resolveArguments

@Nullable
protected Object[] resolveArguments(@Nullable
 Object arguments)
                             throws JspException

Resolve the given arguments Object into an arguments array.

Parameters:

arguments - the specified arguments Object

Returns:

the resolved arguments as array

Throws:

JspException - if argument conversion failed

See Also:

• setArguments(java.lang.Object)

writeMessage

protected void writeMessage(String msg)
                     throws IOException

Write the message to the page.

Can be overridden in subclasses, e.g. for testing purposes.

Parameters:

msg - the message to write

Throws:

IOException - if writing failed

getMessageSource

protected MessageSource getMessageSource()

Use the current RequestContext's application context as MessageSource.

getNoSuchMessageExceptionDescription

protected String getNoSuchMessageExceptionDescription(NoSuchMessageException ex)

Return default exception message.