com.devsphere.xml.taglib.output.tag
Class OutputSupport

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

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:

Attribute, Attributes, Comment, Data, Element, Fragment, PI

public abstract class OutputSupport

extends CommonSupport

This class provides support for XML output tag handlers.

See Also:

Serialized Form

Field Summary

protected OutputSupport	ancestor The tag handler of the nearest ancestor tag.
protected java.io.Writer	previousOut The previous JSP out used by the serializer object.
protected Serializer	serializer An object used to produce the XML content.

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

OutputSupport()

Method Summary

int	doEndTag() Calls endOutput() and returns EVAL_PAGE.
int	doStartTag() Calls initOutput() and then startOutput().
protected void	emptyComment() Produces an empty comment.
protected abstract void	endOutput() Subclasses must implement this method to end the XML content that the handled tag is supposed to produce.
protected void	init() Initializes the fields of this tag handler.
protected void	initOutput() Initializes this tag handler for output, finding the nearest ancestor tag so that the current tag can be validated and handled within its context.
protected boolean	shouldBufferContent() Returns false.
protected boolean	shouldIgnoreContent() Returns false.
protected abstract void	startOutput() Subclasses must implement this method to start the XML content that the handled tag is supposed to produce.

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

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

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

doAfterBody, 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 OutputSupport ancestor

The tag handler of the nearest ancestor tag.

serializer

protected Serializer serializer

An object used to produce the XML content.

previousOut

protected java.io.Writer previousOut

The previous JSP out used by the serializer object.

Constructor Detail

OutputSupport

public OutputSupport()

Method Detail

init

protected void init()

Initializes the fields of this tag handler.

Overrides:

init in class CommonSupport

shouldIgnoreContent

protected boolean shouldIgnoreContent()

Returns false. Subclasses may override this method to return true if the body content of the handled tag should be ignored during the execution of the JSP page.

Returns:

a flag indicating whether the body content of this tag should be ignored or evaluated

shouldBufferContent

protected boolean shouldBufferContent()

Returns false. Subclasses may override this method to return true if the body content of the handled tag should be buffered during the execution of the JSP page.

Returns:

a flag indicating if the body content of this tag should be buffered

initOutput

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

Initializes this tag handler for output, 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

startOutput

protected abstract void startOutput()
                             throws javax.servlet.jsp.JspException,
                                    org.xml.sax.SAXException

Subclasses must implement this method to start the XML content that the handled tag is supposed to produce.

Throws:

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

org.xml.sax.SAXException - to signal an error

endOutput

protected abstract void endOutput()
                           throws javax.servlet.jsp.JspException,
                                  org.xml.sax.SAXException

Subclasses must implement this method to end the XML content that the handled tag is supposed to produce.

Throws:

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

org.xml.sax.SAXException - to signal an error

emptyComment

protected void emptyComment()
                     throws javax.servlet.jsp.JspException,
                            org.xml.sax.SAXException

Produces an empty comment. This forces the serializer to flush its buffer. Those empty comments are eliminated by a filter and do not show up in the final output.

Throws:

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

org.xml.sax.SAXException - to signal an error

doStartTag

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

Calls initOutput() and then startOutput(). This method returns

• SKIP_BODY if shouldIgnoreContent() returns true
• EVAL_BODY_BUFFERED if shouldIgnoreContent() returns false and shouldBufferContent() returns true
• EVAL_BODY_INCLUDE if shouldIgnoreContent() returns false and shouldBufferContent() returns false

Specified by:

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

Overrides:

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

Returns:

a code that tells the Servlet container what to do with the body content of the handled tag.

Throws:

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

doEndTag

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

Calls endOutput() and 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