Examples of javax.servlet.jsp.tagext.BodyTag

javax.servlet.jsp.tagext.BodyTag
The BodyTag interface extends IterationTag by defining additional methods that let a tag handler manipulate the content of evaluating its body.
It is the responsibility of the tag handler to manipulate the body content. For example the tag handler may take the body content, convert it into a String using the bodyContent.getString method and then use it. Or the tag handler may take the body content and write it out into its enclosing JspWriter using the bodyContent.writeOut method.
A tag handler that implements BodyTag is treated as one that implements IterationTag, except that the doStartTag method can return SKIP_BODY, EVAL_BODY_INCLUDE or EVAL_BODY_BUFFERED.
If EVAL_BODY_INCLUDE is returned, then evaluation happens as in IterationTag.
If EVAL_BODY_BUFFERED is returned, then a BodyContent object will be created (by code generated by the JSP compiler) to capture the body evaluation. The code generated by the JSP compiler obtains the BodyContent object by calling the pushBody method of the current pageContext, which additionally has the effect of saving the previous out value. The page compiler returns this object by calling the popBody method of the PageContext class; the call also restores the value of out.
The interface provides one new property with a setter method and one new action method.
Properties
There is a new property: bodyContent, to contain the BodyContent object, where the JSP Page implementation object will place the evaluation (and reevaluation, if appropriate) of the body. The setter method (setBodyContent) will only be invoked if doStartTag() returns EVAL_BODY_BUFFERED.
Methods
In addition to the setter method for the bodyContent property, there is a new action methods: doInitBody(), which is invoked right after setBodyContent() and before the body evaluation. This method is only invoked if doStartTag() returns EVAL_BODY_BUFFERED.
Lifecycle
Lifecycle details are described by the transition diagram below. Exceptions that are thrown during the computation of doStartTag(), setBodyContent(), doInitBody(), BODY, doAfterBody() interrupt the execution sequence and are propagated up the stack, unless the tag handler implements the TryCatchFinally interface; see that interface for details.

Empty and Non-Empty Action
If the TagLibraryDescriptor file indicates that the action must always have an empty action, by an <body-content> entry of "empty", then the doStartTag() method must return SKIP_BODY. Otherwise, the doStartTag() method may return SKIP_BODY, EVAL_BODY_INCLUDE, or EVAL_BODY_BUFFERED.
If SKIP_BODY is returned the body is not evaluated, and doEndTag() is invoked.
If EVAL_BODY_INCLUDE is returned, setBodyContent() is not invoked, doInitBody() is not invoked, the body is evaluated and "passed through" to the current out, doAfterBody() is invoked and then, after zero or more iterations, doEndTag() is invoked.
If EVAL_BODY_BUFFERED is returned, setBodyContent() is invoked, doInitBody() is invoked, the body is evaluated, doAfterBody() is invoked, and then, after zero or more iterations, doEndTag() is invoked.

                        return TransformControl.SKIP_BODY;
                    }
                    case BodyTag.EVAL_BODY_BUFFERED: {
                        if(isBodyTag) {
                            initBuffer();
                            BodyTag btag = (BodyTag)tag;
                            btag.setBodyContent(this);
                            btag.doInitBody();
                        }
                        else {
                            throw new TemplateModelException("Can't buffer body since " + tag.getClass().getName() + " does not implement BodyTag.");
                        }
                        // Intentional fall-through

View Full Code Here

                {
                    IterationTag iterationTag = (IterationTag) this.tag;
                    if ((status == BodyTag.EVAL_BODY_BUFFERED)
                        && (this.tag instanceof BodyTag))
                    {
                        BodyTag bodyTag = (BodyTag) this.tag;
                        body = pageContext.pushBody();
                        if (log.isDebugEnabled())
                        {
                            log.debug("Pushed body content ["
                                + body.getString() + "]");
                        }
                        bodyTag.setBodyContent(body);
                        bodyTag.doInitBody();
                    }
                    int iteration = 0;
                    do
                    {
                        fireEvalBody(iteration, body);

View Full Code Here

                {
                    IterationTag iterationTag = (IterationTag) this.tag;
                    if ((status == BodyTag.EVAL_BODY_BUFFERED)
                        && (this.tag instanceof BodyTag))
                    {
                        BodyTag bodyTag = (BodyTag) this.tag;
                        body = pageContext.pushBody();
                        if (log.isDebugEnabled())
                        {
                            log.debug("Pushed body content ["
                                + body.getString() + "]");
                        }
                        bodyTag.setBodyContent(body);
                        bodyTag.doInitBody();
                    }
                    int iteration = 0;
                    do
                    {
                        fireEvalBody(iteration, body);

View Full Code Here

                {
                    IterationTag iterationTag = (IterationTag) this.tag;
                    if ((status == BodyTag.EVAL_BODY_BUFFERED)
                        && (this.tag instanceof BodyTag))
                    {
                        BodyTag bodyTag = (BodyTag) this.tag;
                        body = pageContext.pushBody();
                        if (log.isDebugEnabled())
                        {
                            log.debug("Pushed body content ["
                                + body.getString() + "]");
                        }
                        bodyTag.setBodyContent(body);
                        bodyTag.doInitBody();
                    }
                    int iteration = 0;
                    do
                    {
                        fireEvalBody(iteration, body);

View Full Code Here

                {
                    IterationTag iterationTag = (IterationTag) this.tag;
                    if ((status == BodyTag.EVAL_BODY_BUFFERED)
                        && (this.tag instanceof BodyTag))
                    {
                        BodyTag bodyTag = (BodyTag) this.tag;
                        body = pageContext.pushBody();
                        if (log.isDebugEnabled())
                        {
                            log.debug("Pushed body content ["
                                + body.getString() + "]");
                        }
                        bodyTag.setBodyContent(body);
                        bodyTag.doInitBody();
                    }
                    int iteration = 0;
                    do
                    {
                        fireEvalBody(iteration, body);

View Full Code Here

                        return TransformControl.SKIP_BODY;
                    }
                    case BodyTag.EVAL_BODY_BUFFERED: {
                        if(isBodyTag) {
                            initBuffer();
                            BodyTag btag = (BodyTag)tag;
                            btag.setBodyContent(this);
                            btag.doInitBody();
                        }
                        else {
                            throw new TemplateModelException("Can't buffer body since " + tag.getClass().getName() + " does not implement BodyTag.");
                        }
                        // Intentional fall-through

View Full Code Here

                        return TransformControl.SKIP_BODY;
                    }
                    case BodyTag.EVAL_BODY_BUFFERED: {
                        if(isBodyTag) {
                            initBuffer();
                            BodyTag btag = (BodyTag)tag;
                            btag.setBodyContent(this);
                            btag.doInitBody();
                        }
                        else {
                            throw new TemplateModelException("Can't buffer body since " + tag.getClass().getName() + " does not implement BodyTag.");
                        }
                        // Intentional fall-through

View Full Code Here

                {
                    IterationTag iterationTag = (IterationTag) this.tag;
                    if ((status == BodyTag.EVAL_BODY_BUFFERED)
                        && (this.tag instanceof BodyTag))
                    {
                        BodyTag bodyTag = (BodyTag) this.tag;
                        body = pageContext.pushBody();
                        if (log.isDebugEnabled())
                        {
                            log.debug("Pushed body content ["
                                + body.getString() + "]");
                        }
                        bodyTag.setBodyContent(body);
                        bodyTag.doInitBody();
                    }
                    int iteration = 0;
                    do
                    {
                        fireEvalBody(iteration, body);

View Full Code Here

TOP

Related Classes of javax.servlet.jsp.tagext.BodyTag

freemarker.ext.jsp.TagTransformModel$TagWriter

org.apache.cactus.extension.jsp.JspTagLifecycle

All source code are property of their respective owners. Java is a trademark of Sun Microsystems, Inc and owned by ORACLE Inc. Contact coftware#gmail.com.