com.devsphere.xml.taglib.process.tag
Class ProcessSupport

java.lang.Object
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  +--javax.servlet.jsp.tagext.TagSupport
        |
        +--javax.servlet.jsp.tagext.BodyTagSupport
              |
              +--com.devsphere.xml.taglib.support.tag.CommonSupport
                    |
                    +--com.devsphere.xml.taglib.process.tag.ProcessSupport

All Implemented Interfaces:

javax.servlet.jsp.tagext.BodyTag, javax.servlet.jsp.tagext.IterationTag, java.io.Serializable, javax.servlet.jsp.tagext.Tag, javax.servlet.jsp.tagext.TryCatchFinally

Direct Known Subclasses:

Data, Element, End, Parse, PI, Start

public abstract class ProcessSupport

extends CommonSupport

This class provides support for XML processing tag handlers. It provides methods for looping over a sequence of SAX events.

See Also:

Serialized Form

Field Summary

protected ProcessSupport	ancestor The tag handler of the nearest ancestor tag
protected EventSupport	event The event handled by this object
protected Handler	handler The event handler
protected int	indentLevel The indent level of the tag

Fields inherited from class com.devsphere.xml.taglib.support.tag.CommonSupport

cachedDebug, cachedLogger, DEBUG_ATTR, DEFAULT_DEBUG, DEFAULT_RESTORE_VALUE, DEFAULT_SCOPE, LOGGER_ATTR, originalValues

Fields inherited from class javax.servlet.jsp.tagext.BodyTagSupport

bodyContent

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

id, pageContext

Fields inherited from interface javax.servlet.jsp.tagext.BodyTag

EVAL_BODY_BUFFERED, EVAL_BODY_TAG

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

EVAL_BODY_AGAIN

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

EVAL_BODY_INCLUDE, EVAL_PAGE, SKIP_BODY, SKIP_PAGE

Constructor Summary

ProcessSupport()

Method Summary

protected abstract boolean	continueLoop() Subclasses must implement this method and return true if the event loop should be continued.
int	doAfterBody() Calls continueLoop().
int	doEndTag() Returns EVAL_PAGE.
void	doFinally() Calls finalizeLoop()
int	doStartTag() Calls initLoop() and then startLoop().
protected void	finalizeLoop() Subclasses may override this method if they need to execute some operations after the event loop is finished.
protected boolean	getEvent() Gets the current parsing event and returns true if this isn't null.
protected void	init() Initializes the fields of this tag handler.
protected void	initLoop() Initializes the event loop, finding the nearest ancestor tag so that the current tag can be validated and handled within its context.
protected void	logEvent() Logs an event if the debug flag is true.
protected void	logEvent(java.lang.String status) Logs an event if the debug flag is true.
protected boolean	removeEvent() Tries to removes the current parsing event in order to make room for another event.
protected abstract boolean	startLoop() Subclasses must implement this method and return true if the event loop should be started.
protected void	validate(CommonSupport ancestor) Verify if the handled tag was placed in the right context.

Methods inherited from class com.devsphere.xml.taglib.support.tag.CommonSupport

checkVarName, checkVarScope, doCatch, eval, evalBoolean, evalDouble, evalInt, evalString, export, export, getAllowedAncestors, getDebug, getLogger, getTagName, log, log, log, restore

Methods inherited from class javax.servlet.jsp.tagext.BodyTagSupport

doInitBody, getBodyContent, getPreviousOut, release, setBodyContent

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

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

Methods inherited from interface javax.servlet.jsp.tagext.Tag

getParent, setPageContext, setParent

Field Detail

ancestor

protected ProcessSupport ancestor

The tag handler of the nearest ancestor tag

handler

protected Handler handler

The event handler

event

protected EventSupport event

The event handled by this object

indentLevel

protected int indentLevel

The indent level of the tag

Constructor Detail

ProcessSupport

public ProcessSupport()

Method Detail

init

protected void init()

Initializes the fields of this tag handler.

Overrides:

init in class CommonSupport

validate

protected void validate(CommonSupport ancestor)
                 throws javax.servlet.jsp.JspException

Verify if the handled tag was placed in the right context. This methods throws a JspException if

• ancestor is null, but the allowed ancestors list is not empty or
• ancestor is not null, but the allowed ancestors list is empty or
• the name of the given ancestor tag is not found in the allowed ancestors list returned by getAllowedAncestors() or
• the ancestor tag is an <p:element> tag with a dom variable. Such tags may not contain tags of this library because a DOM sub-tree is constructed instead of generating SAX events.

Overrides:

validate in class CommonSupport

Parameters:

ancestor - the tag handler of an ancestor whose name is searched in the list of allowed ancestors

Throws:

javax.servlet.jsp.JspException - to signal a tag validation error

getEvent

protected boolean getEvent()

Gets the current parsing event and returns true if this isn't null.

Returns:

true if an event is available for processing

removeEvent

protected boolean removeEvent()

Tries to removes the current parsing event in order to make room for another event.

Returns:

true if the event was removed

logEvent

protected void logEvent()

Logs an event if the debug flag is true.

logEvent

protected void logEvent(java.lang.String status)

Logs an event if the debug flag is true.

Parameters:

status - a string describing the status of the event

initLoop

protected void initLoop()
                 throws javax.servlet.jsp.JspException

Initializes the event loop, finding the nearest ancestor tag so that the current tag can be validated and handled within its context.

Throws:

javax.servlet.jsp.JspException - to signal a tag validation error

startLoop

protected abstract boolean startLoop()
                              throws javax.servlet.jsp.JspException

Subclasses must implement this method and return true if the event loop should be started.

Returns:

true if the event loop should be started

Throws:

javax.servlet.jsp.JspException - to signal an error

continueLoop

protected abstract boolean continueLoop()
                                 throws javax.servlet.jsp.JspException

Subclasses must implement this method and return true if the event loop should be continued.

Returns:

true if the event loop should be continued

Throws:

javax.servlet.jsp.JspException - to signal an error

finalizeLoop

protected void finalizeLoop()

Subclasses may override this method if they need to execute some operations after the event loop is finished.

doStartTag

public int doStartTag()
               throws javax.servlet.jsp.JspException

Calls initLoop() and then startLoop(). If the latter returns true, this method returns EVAL_BODY_INCLUDE so that the body of the tag is evaluated getting the chance to process one or more parsing events. Otherwise it returns SKIP_BODY.

Specified by:

doStartTag in interface javax.servlet.jsp.tagext.Tag

Overrides:

doStartTag in class javax.servlet.jsp.tagext.BodyTagSupport

Returns:

EVAL_BODY_INCLUDE or SKIP_BODY depending on the value returned by startLoop()

Throws:

javax.servlet.jsp.JspException - to signal an error

doAfterBody

public int doAfterBody()
                throws javax.servlet.jsp.JspException

Calls continueLoop(). If that returns true, this method returns EVAL_BODY_AGAIN so that the body of the tag is re-evaluated getting the chance to process new events. Otherwise it returns SKIP_BODY.

Specified by:

doAfterBody in interface javax.servlet.jsp.tagext.IterationTag

Overrides:

doAfterBody in class javax.servlet.jsp.tagext.BodyTagSupport

Returns:

EVAL_BODY_AGAIN or SKIP_BODY depending on the value returned by continueLoop()

Throws:

javax.servlet.jsp.JspException - to signal an error

doEndTag

public int doEndTag()
             throws javax.servlet.jsp.JspException

Returns EVAL_PAGE.

Specified by:

doEndTag in interface javax.servlet.jsp.tagext.Tag

Overrides:

doEndTag in class javax.servlet.jsp.tagext.BodyTagSupport

Returns:

EVAL_PAGE.

javax.servlet.jsp.JspException

doFinally

public void doFinally()

Calls finalizeLoop()

Specified by:

doFinally in interface javax.servlet.jsp.tagext.TryCatchFinally

Overrides:

doFinally in class CommonSupport