Package javax.faces.webapp

Class UIComponentClassicTagBase

  • All Implemented Interfaces:
    BodyTag, IterationTag, JspIdConsumer, JspTag, Tag
    Direct Known Subclasses:
    UIComponentELTag, UIComponentTag

    public abstract class UIComponentClassicTagBase
extends UIComponentTagBase
implements JspIdConsumer, BodyTag

    UIComponentTagBase is the base class for all JSP tags that use the "classic" JSP tag interface that correspond to a UIComponent instance in the view. In Faces 1.2, all component tags are BodyTag instances to allow for the execution of the page to build the component tree, but not render it. Rendering happens only after the component tree is completely built.

    UIComponentTag extends UIComponentClassicTagBase to add support for properties that conform to the Faces 1.1 EL.

    UIComponentELTag extends UIComponentClassicTagBase class to add support for properties that conform to the EL API.

    The default implementation allows the proper interweaving of template text, non-Faces JSP tag output, and Faces component tag output in the same page, as expected by the page author.

    The CASE markers in the following example will be cited in the method descriptions of this class.

    • CASE 1 describes template text and/or non-component custom tag output occurring as the child of a component tag, but before the first component tag child of that component tag.

    • CASE 2 describes template text and/or non-component custom tag output occurring between two sibling component tags.

    • CASE 3 describes template text and/or non-component custom tag output occurring as the child content of an <f:verbatim> tag at any point in the page.

    • CASE 4 describes template text and/or non-component custom tag output occurring between the last child component tag and its enclosing parent component tag's end tag.

    

 <h:panelGrid style="color:red" border="4" columns="2">
 CASE 1
 <h:outputText value="component 1"/>
 CASE 2
 <h:outputText value="component 2"/>
 <f:verbatim>CASE 3</f:verbatim>
 <c:out value="${pageScope.CASE4}" />
 </h:panelGrid>

    The preceding arrangement of faces component tags, must yield markup that will render identically to the following (assuming that ${pageScope.CASE4} evaluates to "CASE 4" without the quotes).

    

 <table border="4" style="color:red">

 <tbody>

 <tr><td>CASE 1</td></tr> <tr><td>component 1</td></tr>

 <tr><td>CASE 2</td> <tr><td>component 2</td></tr>

 <tr><td>CASE 3</td> <td>CASE 4</td></tr>

 </tbody>

 </table>

    • Field Detail

      • UNIQUE_ID_PREFIX

        protected static final java.lang.String UNIQUE_ID_PREFIX
        Used as the prefix for ids. This is necessary to avoid uniqueness conflicts with the transient verbatim components.
        See Also:
        Constant Field Values

      • bodyContent

        protected BodyContent bodyContent

        The bodyContent for this tag handler.

      • pageContext

        protected PageContext pageContext

        The JSP PageContext for the page we are embedded in.

    • Constructor Detail

      • UIComponentClassicTagBase

        public UIComponentClassicTagBase​()

    • Method Detail

      • getDoStartValue

        protected int getDoStartValue​()
                       throws JspException

        Return the flag value that should be returned from the doStart() method when it is called. Subclasses may override this method to return the appropriate value.

        Returns:
        the value to return from doStart()
        Throws:
        JspException - to cause doStart() to throw an exception

      • getDoEndValue

        protected int getDoEndValue​()
                     throws JspException

        Return the flag value that should be returned from the doEnd() method when it is called. Subclasses may override this method to return the appropriate value.

        Returns:
        the value to return from doEnd()
        Throws:
        JspException - to cause doEnd() to throw an exception

      • encodeBegin

        protected void encodeBegin​()
                    throws java.io.IOException
        Deprecated. No encoding is done during JSP page execution. Encoding is deferred until the page has completed executing to allow the entire tree to be built before any encoding occurs.

        Delegate to the encodeBegin() method of our corresponding UIComponent. This method is called from doStartTag(). Normally, delegation occurs unconditionally; however, this method is abstracted out so that advanced tags can conditionally perform this call.

        Throws:
        java.io.IOException - if an input/output error occurs

      • encodeChildren

        protected void encodeChildren​()
                       throws java.io.IOException
        Deprecated. No encoding is done during JSP page execution. Encoding is deferred until the page has completed executing to allow the entire tree to be built before any encoding occurs.

        Delegate to the encodeChildren() method of our corresponding UIComponent. This method is called from doStartTag(). Normally, delegation occurs unconditionally; however, this method is abstracted out so that advanced tags can conditionally perform this call.

        Throws:
        java.io.IOException - if an input/output error occurs

      • encodeEnd

        protected void encodeEnd​()
                  throws java.io.IOException
        Deprecated. No encoding is done during JSP page execution. Encoding is deferred until the page has completed executing to allow the entire tree to be built before any encoding occurs.

        Delegate to the encodeEnd() method of our corresponding UIComponent. This method is called from doStartTag(). Normally, delegation occurs unconditionally; however, this method is abstracted out so that advanced tags can conditionally perform this call.

        Throws:
        java.io.IOException - if an input/output error occurs

      • setPageContext

        public void setPageContext​(PageContext pageContext)

        Set the PageContext of the page containing this tag instance.

        Specified by:
        setPageContext in interface Tag
        Parameters:
        pageContext - The enclosing PageContext

      • setParent

        public void setParent​(Tag parent)

        Set the Tag that is the parent of this instance.

        Specified by:
        setParent in interface Tag
        Parameters:
        parent - The new parent Tag

      • findComponent

        protected UIComponent findComponent​(FacesContext context)
                             throws JspException

        Find and return the UIComponent, from the component tree, that corresponds to this tag handler instance. If there is no such UIComponent, create one and add it as a child or facet of the UIComponent associated with our nearest enclosing UIComponentTag. The process for locating or creating the component is:

        1. If we have previously located this component, return it.
        2. Locate the parent component by looking for a parent UIComponentTag instance, and ask it for its component. If there is no parent UIComponentTag instance, this tag represents the root component, so get it from the current Tree and return it.
        3. If this UIComponentTag instance has the facetName attribute set, ask the parent UIComponent for a facet with this name. If not found, create one, call setProperties() with the new component as a parameter, and register it under this name. Return the found or created facet UIComponent.
        4. Determine the component id to be assigned to the new component, as follows: if this UIComponentTag has an id attribute set, use that value; otherwise, generate an identifier that is guaranteed to be the same for this UIComponent every time this page is processed (i.e. one based on the location of all UIComponentTag instances without an id attribute set).
        5. Ask the parent UIComponent for a child with this identifier. If not found, create one, call setProperties() with the new component as a parameter, and register it as a child with this identifier. Return the found or created child UIComponent.

        When creating a component, the process is:

        1. Retrieve the component type by calling UIComponentTagBase.getComponentType()
        2. If the component has a binding attribute, create an expression from it, and call Application.createComponent(java.lang.String) with that expression, the FacesContext, and the component type. Store the expression using the key "binding".
        3. Otherwise, call Application.createComponent(java.lang.String) with only the component type.
        4. Call setProperties().
        5. Add the new component as a child or facet of its parent
        Parameters:
        context - the FacesContext for the current request.
        Returns:
        the found component
        Throws:
        JspException - if an unexpected condition arises while finding the component

      • getParentUIComponentClassicTagBase

        public static UIComponentClassicTagBase getParentUIComponentClassicTagBase​(PageContext context)

        Locate and return the nearest enclosing UIComponentClassicTagBase if any; otherwise, return null.

        Parameters:
        context - PageContext for the current page
        Returns:
        the parent tag

      • getIndexOfNextChildTag

        protected int getIndexOfNextChildTag​()
        Description copied from class: UIComponentTagBase

        Return the index of the next child to be added as a child of this tag. The default implementation maintains a list of created components and returns the size of the list.

        Specified by:
        getIndexOfNextChildTag in class UIComponentTagBase
        Returns:
        the index

      • addFacet

        protected void addFacet​(java.lang.String name)
        Description copied from class: UIComponentTagBase

        Add the facet name of the specified facet to the list of facet names created or located by nested UIComponentTags processing this request.

        Specified by:
        addFacet in class UIComponentTagBase
        Parameters:
        name - Facet name to be added

      • createVerbatimComponentFromBodyContent

        protected UIComponent createVerbatimComponentFromBodyContent​()

        Create a transient UIOutput component from the body content, of this tag instance or return null if there is no body content, the body content is whitespace, or the body content is a comment.

        Returns:
        the component

      • createVerbatimComponent

        protected UIOutput createVerbatimComponent​()

        Use the Application instance to create a new component with the following characteristics.

        componentType is javax.faces.HtmlOutputText.

        transient is true.

        escape is false.

        id is FacesContext.getViewRoot().createUniqueId()

        Returns:
        the component

      • addVerbatimBeforeComponent

        protected void addVerbatimBeforeComponent​(UIComponentClassicTagBase parentTag,
                                          UIComponent verbatim,
                                          UIComponent component)

        Add verbatim as a sibling of component in component in the parent's child list. verbatim is added to the list at the position immediatly preceding component.

        Parameters:
        parentTag - the parent tag
        verbatim - the verbatim to add before the component
        component - the component to be added after the component

      • addVerbatimAfterComponent

        protected void addVerbatimAfterComponent​(UIComponentClassicTagBase parentTag,
                                         UIComponent verbatim,
                                         UIComponent component)

        Add verbatim as a sibling of component in component in the parent's child list. verbatim is added to the list at the position immediatly following component.

        Parameters:
        parentTag - the parent tag
        verbatim - the verbatim to add after the component
        component - the component to be added before the component

      • doEndTag

        public int doEndTag​()
             throws JspException

        Perform any processing necessary to handle the content implications of CASE 3 in the class description.

        The default implementation, which is intended to be sufficient for most components, calls createVerbatimComponentFromBodyContent() on this instance and adds it as a child of the component for this tag's component at the end of the child list. In addition, the following housekeeping steps are taken.

        • Retrieve from the UIComponent the set of component ids of child components created by UIComponentTag instances the last time this page was processed (if any). Compare it to the list of children created during this page processing pass, and remove all children present in the old list but not the new. Save the new list as a component attribute so that it gets saved as part of the component's state.
        • Retrieve from the UIComponent the set of facet names of facets created by UIComponentTag instances the last time this page was processed (if any). Compare it to the list of facets created during this page processing pass, and remove all facets present in the old list but not the new. Save the new list as a component attribute so that it gets saved as part of the component's state.
        • Release all references to the component, and pop it from the component stack for this response, removing the stack if this was the outermost component.

        The flag value to be returned is acquired by calling the getDoEndValue() method, which tag subclasses may override if they do not want the default value.

        Specified by:
        doEndTag in interface Tag
        Returns:
        indication of whether to continue evaluating the JSP page.
        Throws:
        JspException - if an error occurs

      • release

        public void release​()

        Release any resources allocated during the execution of this tag handler.

        Specified by:
        release in interface Tag

      • getDoAfterBodyValue

        protected int getDoAfterBodyValue​()
                           throws JspException

        Return the flag value that should be returned from the doAfterBody() method when it is called. Subclasses may override this method to return the appropriate value.

        Returns:
        the value to return from doAfterBody()
        Throws:
        JspException - if an unexpected condition arises while getting the value

      • setBodyContent

        public void setBodyContent​(BodyContent bodyContent)

        Set the bodyContent for this tag handler. This method is invoked by the JSP page implementation object at most once per action invocation, before doInitiBody(). This method will not be invoked for empty tags or for non-empty tags whose doStartTag() method returns SKIP_BODY or EVAL_BODY_INCLUDE.

        Specified by:
        setBodyContent in interface BodyTag
        Parameters:
        bodyContent - The new BodyContent for this tag
        See Also:
        BodyTag.doInitBody(), IterationTag.doAfterBody()

      • getPreviousOut

        public JspWriter getPreviousOut​()

        Get the JspWriter from our BodyContent.

        Returns:
        the writer

      • getBodyContent

        public BodyContent getBodyContent​()

      • doInitBody

        public void doInitBody​()
                throws JspException

        Prepare for evaluation of the body. This method is invoked by the JSP page implementation object after setBodyContent() and before the first time the body is to be evaluated. This method will not be invoked for empty tags or for non-empty tags whose doStartTag() method returns SKIP_BODY or EVAL_BODY_INCLUDE.

        Specified by:
        doInitBody in interface BodyTag
        Throws:
        JspException - if an error is encountered
        See Also:
        IterationTag.doAfterBody()

      • doAfterBody

        public int doAfterBody​()
                throws JspException

        Perform any processing necessary to handle the content implications of CASE 4 in the class description.

        Return result from getDoAfterBodyValue()

        Specified by:
        doAfterBody in interface IterationTag
        Returns:
        whether additional evaluations of the body are desired
        Throws:
        JspException - if an error is encountered

      • getId

        protected java.lang.String getId​()

        Return the id value assigned by the page author.

        Returns:
        the id of this tag

      • getFacesJspId

        protected java.lang.String getFacesJspId​()

        If this method has been called before on this tag's useful lifetime (before release() was called), return the previously returned value. Otherwise, if getJspId() returns non-null, prepend UNIQUE_ID_PREFIX to the jspId and return the result.

        Returns:
        the value as specified above

      • getCreatedComponents

        protected java.util.List<java.lang.String> getCreatedComponents​()
        Returns the List of UIComponent ids created or located by nested UIComponentTags while processing the current request.
        Returns:
        the created components

      • setJspId

        public void setJspId​(java.lang.String id)

        Defined on JspIdConsumer. This method is called by the container before doStartTag(). The argument is guaranteed to be unique within the page.

        IMPLEMENTATION NOTE: This method will detect where we are in an include and assign a unique ID for each include in a particular 'logical page'. This allows us to avoid possible duplicate ID situations for included pages that have components without explicit IDs.

        Specified by:
        setJspId in interface JspIdConsumer
        Parameters:
        id - the container generated id for this tag, guaranteed to be unique within the page.

      • getJspId

        public java.lang.String getJspId​()

      • setProperties

        protected abstract void setProperties​(UIComponent component)

        Override properties and attributes of the specified component, if the corresponding properties of this tag handler instance were explicitly set. This method must be called ONLY if the specified UIComponent was in fact created during the execution of this tag handler instance, and this call will occur BEFORE the UIComponent is added to the view.

        Tag subclasses that want to support additional set properties must ensure that the base class setProperties() method is still called. A typical implementation that supports extra properties foo and bar would look something like this:

         protected void setProperties(UIComponent component) {
   super.setProperties(component);
   if (foo != null) {
     component.setAttribute("foo", foo);
   }
   if (bar != null) {
     component.setAttribute("bar", bar);
   }
 }

        The default implementation overrides the following properties:

        • rendered - Set if a value for the rendered property is specified for this tag handler instance.
        • rendererType - Set if the getRendererType() method returns a non-null value.
        Parameters:
        component - UIComponent whose properties are to be overridden

      • hasBinding

        protected abstract boolean hasBinding​()

        Return true if this component has a non-null binding attribute. This method is necessary to allow subclasses that expose the binding property as an Faces 1.1 style EL property as well as subclasses that expose it as an EL API property.

        Returns:
        whether or not this component has a binding attribute

      • getComponentInstance

        public UIComponent getComponentInstance​()

        Return the UIComponent instance that is associated with this tag instance. This method is designed to be used by tags nested within this tag, and only returns useful results between the execution of doStartTag() and doEndTag() on this tag instance.

        Specified by:
        getComponentInstance in class UIComponentTagBase
        Returns:
        the component

      • getCreated

        public boolean getCreated​()

        Return true if we dynamically created a new component instance during execution of this tag. This method is designed to be used by tags nested within this tag, and only returns useful results between the execution of doStartTag() and doEndTag() on this tag instance.

        Specified by:
        getCreated in class UIComponentTagBase
        Returns:
        the result as specified above

      • getFacesContext

        protected FacesContext getFacesContext​()
        Description copied from class: UIComponentTagBase

        Return the FacesContext instance for the current request. This value will be non-null only from the beginning of doStartTag() through the end of doEndTag() for each tag instance.

        Specified by:
        getFacesContext in class UIComponentTagBase
        Returns:
        the FacesContext for the current request.

      • getFacetName

        protected java.lang.String getFacetName​()

        Return the facet name that we should be stored under, if any; otherwise, return null (indicating that we will be a child component).

        Returns:
        the name of the facet