Class NullTag

  • All Implemented Interfaces:
    org.apache.commons.jelly.Tag

    public class NullTag
    extends org.apache.commons.jelly.TagSupport

    A tag handler class for specifying null values.

    This tag handler class can appear in the body of a tag implementing the ValueSupport interface. It sets the value of its parent tag to null.

    The main use case for this tag is to be placed in the body of a ParameterTag or SetPropertyTag. These tags require a value to set; otherwise they throw an exception. Using this tag means "there is a value, but it is null".

    Version:
    $Id: NullTag.java 205 2012-01-29 18:29:57Z oheger $
    Author:
    Oliver Heger
    • Field Summary

      • Fields inherited from class org.apache.commons.jelly.TagSupport

        body, context, hasTrimmed, parent, shouldTrim
    • Constructor Summary

      Constructors 
      Constructor Description
      NullTag()  
    • Method Summary

      All Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      void doTag​(org.apache.commons.jelly.XMLOutput out)
      Executes this tag.
      • Methods inherited from class org.apache.commons.jelly.TagSupport

        findAncestorWithClass, findAncestorWithClass, findAncestorWithClass, findAncestorWithClass, findAncestorWithClass, findAncestorWithClass, getBody, getBodyText, getBodyText, getContext, getParent, invokeBody, isEscapeText, isTrim, setBody, setContext, setEscapeText, setParent, setTrim, trimBody
    • Constructor Detail

      • NullTag

        public NullTag()
    • Method Detail

      • doTag

        public void doTag​(org.apache.commons.jelly.XMLOutput out)
                   throws org.apache.commons.jelly.JellyTagException
        Executes this tag. This implementation checks whether the parent tag implements the ValueSupport interface. If this is the case, its value is set to null. Otherwise an exception is thrown.
        Parameters:
        out - the output object
        Throws:
        org.apache.commons.jelly.JellyTagException - if the tag is used incorrectly