Package com.aoindustries.encoding.taglib.legacy

Class EncodingFilteredBodyTag

java.lang.Object

javax.servlet.jsp.tagext.TagSupport

javax.servlet.jsp.tagext.BodyTagSupport

com.aoindustries.encoding.taglib.legacy.EncodingFilteredBodyTag

All Implemented Interfaces:

Serializable, BodyTag, IterationTag, JspTag, Tag, TryCatchFinally

Direct Known Subclasses:

EncodingTag, JavaScriptTag, JsonTag, LdJsonTag, MysqlTag, PsqlTag, ShTag, TextTag, UrlTag, XhtmlAttributeTag, XhtmlTag

public abstract class EncodingFilteredBodyTag
extends BodyTagSupport
implements TryCatchFinally

An implementation of BodyTagSupport that automatically validates its content and automatically encodes its output correctly given its context. It also validates its own output when used in a non-validating context. For higher performance, it filters the output from its body instead of buffering.

The content validation is primarily focused on making sure the contained data is properly encoded. This is to avoid data corruption or intermingling of data and code. It does not go through great lengths such as ensuring that XHTML Strict is valid or JavaScript will run correctly.

In additional to checking that its contents are well behaved, it also is well behaved for its container by properly encoding its output for its context. To determine its context, it uses the content type of the currently registered RequestEncodingContext to perform proper encoding. If it fails to find any such context, it uses the content type of the HttpServletResponse.

Finally, if no existing RequestEncodingContext is found, this will validate its own output against the content type of the HttpServletResponse to make sure it is well-behaved.

Author:

AO Industries, Inc.

See Also:

Serialized Form

Field Summary

Fields

Modifier and Type	Field	Description
static int	EVAL_BODY_FILTERED	Return value for doStartTag(java.io.Writer).

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

Constructors

Constructor	Description
EncodingFilteredBodyTag()

Method Summary

Modifier and Type	Method	Description
int	doAfterBody()	Deprecated. You should probably be implementing in doAfterBody(java.io.Writer)
protected int	doAfterBody(Writer out)	While the out JspWriter is still replaced to output the proper content type, this version of doAfterBody() is called.
void	doCatch(Throwable t)
int	doEndTag()	Deprecated. You should probably be implementing in doEndTag(java.io.Writer)
protected int	doEndTag(Writer out)	While the out JspWriter is still replaced to output the proper content type, this version of doEndTag() is called.
void	doFinally()
void	doInitBody()	The only way to replace the "out" variable in the generated JSP is to use BodyTag.EVAL_BODY_BUFFERED.
int	doStartTag()	Deprecated. You should probably be implementing in doStartTag(java.io.Writer)
protected int	doStartTag(Writer out)	Once the out JspWriter has been replaced to output the proper content type, this version of doStartTag() is called.
abstract MediaType	getContentType()	Gets the type of data that is contained by this tag.
protected void	setMediaEncoderOptions(MediaEncoder mediaEncoder)	Sets the media encoder options.
protected void	writeEncoderPrefix(MediaEncoder mediaEncoder, JspWriter out)
protected void	writeEncoderSuffix(MediaEncoder mediaEncoder, JspWriter out)
protected void	writePrefix(MediaType containerType, Writer out)	Writes any prefix in the container's media type.
protected void	writeSuffix(MediaType containerType, Writer out)	Writes any suffix in the container's media type.

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

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

EVAL_BODY_FILTERED

public static final int EVAL_BODY_FILTERED

Return value for doStartTag(java.io.Writer). It will be converted to either Tag.EVAL_BODY_INCLUDE or BodyTag.EVAL_BODY_BUFFERED, as appropriate to the given filtering and validation.

See Also:

Constant Field Values

Constructor Detail

EncodingFilteredBodyTag

public EncodingFilteredBodyTag()

Method Detail

getContentType

public abstract MediaType getContentType()

Gets the type of data that is contained by this tag. This is also the output type.

doStartTag

@Deprecated
public int doStartTag()
               throws JspException

Deprecated.

You should probably be implementing in doStartTag(java.io.Writer)

Specified by:

doStartTag in interface Tag

Overrides:

doStartTag in class BodyTagSupport

Throws:

JspException

See Also:

doStartTag(java.io.Writer)

doStartTag

protected int doStartTag(Writer out)
                  throws JspException,
                         IOException

Once the out JspWriter has been replaced to output the proper content type, this version of doStartTag() is called.

Parameters:

out - the output. If passed-through, this will be a JspWriter

Returns:

Must return either EVAL_BODY_FILTERED (the default) or Tag.SKIP_BODY

Throws:

JspException

IOException

doInitBody

public void doInitBody()
                throws JspException

The only way to replace the "out" variable in the generated JSP is to use BodyTag.EVAL_BODY_BUFFERED. Without this, any writer given to JspContext.pushBody(java.io.Writer) is not used. We don't actually want to buffer the content, but only want to filter and validate the data on-the-fly.

To workaround this issue, this very hackily replaces the writer field directly on the BodyContentImpl. When unable to replace the field, falls back to using the standard buffering (much less desirable).

This is similar to the direct field access performed by BodyContentImplCoercionOptimizerInitializer.

Specified by:

doInitBody in interface BodyTag

Overrides:

doInitBody in class BodyTagSupport

Throws:

JspException

doAfterBody

@Deprecated
public int doAfterBody()
                throws JspException

Deprecated.

You should probably be implementing in doAfterBody(java.io.Writer)

Specified by:

doAfterBody in interface IterationTag

Overrides:

doAfterBody in class BodyTagSupport

Throws:

JspException

See Also:

doAfterBody(java.io.Writer)

doAfterBody

protected int doAfterBody(Writer out)
                   throws JspException,
                          IOException

While the out JspWriter is still replaced to output the proper content type, this version of doAfterBody() is called.

Parameters:

out - the output. If passed-through, this will be a JspWriter

Returns:

Must return either Tag.SKIP_BODY (the default) or IterationTag.EVAL_BODY_AGAIN

Throws:

JspException

IOException

doEndTag

@Deprecated
public int doEndTag()
             throws JspException

Deprecated.

You should probably be implementing in doEndTag(java.io.Writer)

Specified by:

doEndTag in interface Tag

Overrides:

doEndTag in class BodyTagSupport

Throws:

JspException

See Also:

doEndTag(java.io.Writer)

doEndTag

protected int doEndTag(Writer out)
                throws JspException,
                       IOException

While the out JspWriter is still replaced to output the proper content type, this version of doEndTag() is called.

Parameters:

out - the output. If passed-through, this will be a JspWriter

Returns:

Must return either Tag.EVAL_PAGE (the default) or Tag.SKIP_PAGE

Throws:

JspException

IOException

doCatch

public void doCatch(Throwable t)
             throws Throwable

Specified by:

doCatch in interface TryCatchFinally

Throws:

Throwable

doFinally

public void doFinally()

Specified by:

doFinally in interface TryCatchFinally

writePrefix

protected void writePrefix(MediaType containerType,
                           Writer out)
                    throws JspException,
                           IOException

Writes any prefix in the container's media type. The output must be valid for the provided type.

This default implementation prints nothing.

Throws:

JspException

IOException

setMediaEncoderOptions

protected void setMediaEncoderOptions(MediaEncoder mediaEncoder)

Sets the media encoder options. This is how subclass tag attributes can effect the encoding.

writeEncoderPrefix

protected void writeEncoderPrefix(MediaEncoder mediaEncoder,
                                  JspWriter out)
                           throws JspException,
                                  IOException

Throws:

JspException

IOException

writeEncoderSuffix

protected void writeEncoderSuffix(MediaEncoder mediaEncoder,
                                  JspWriter out)
                           throws JspException,
                                  IOException

Throws:

JspException

IOException

writeSuffix

protected void writeSuffix(MediaType containerType,
                           Writer out)
                    throws JspException,
                           IOException

Writes any suffix in the container's media type. The output must be valid for the provided type.

This default implementation prints nothing.

Throws:

JspException

IOException