Question: TLD and custom Tag Usage.

Question

Hi, I am new to the custom tags and I am confused with one of the examples.
          The TLD has
          <tag>
          <name>item</name>
          <tagclass>com.taglib.wdjsp.mut.OutlineItemTag</tagclass>
          <bodycontent>JSP</bodycontent>
          <info>
          Delineates an item, possibly including subitems,
          within a nested outline.
          </info>
          <attribute>
          <name>text</name>
          <required>true</required>
          <rtexprvalue>true</rtexprvalue>
          </attribute>
          </tag>
          This TLD specifies that the tag has body content that is JSP and not empty.
          The author uses the tag in the JSP page in the following way..
          <mut:item text="What is JSP"/>
          <mut:item text="Evolution of dynamic content technologies">
          <mut:item text="Common Gateway Interface"/>
          </mut:item>
          I wonder why the usage "<mut:item text="What is JSP"/>" - where the
          bodycontent is empty - does not violate the TLD.
          Is the bodycontent optional even if it is specified in TLD. What if it is
          tagdependent?
          thanks - Sri
          

Answer 1

then in your code
public void setEnabled(String enabled) {
this.enabled = true;
in your endtag reset the boolean to false;
IMO, a cleaner approach would be
private boolean enabled = false;
public void setEnabled(boolean enabled) {
     this.enabled = enabled;
}The advanatge is that
<foo other_attributes enabled= "false"/> and
<foo other_attributes/> will both evaluate to false;
<foo other_attributes enabled= "true"/> will evaluate to true
<foo other_attributes enabled= "will_this_work"/> will give an exception
as the container cannot resolve it to a boolean value so that users will
be forced to use true or false (or skip the attribute) which is how it
should be.
Also note the container cannot convert runtime expressions to boolean
values. So if there's a String variable,say prompt in scope that has the
value true, then<%
String prompt = "true";
pageContext.setAttribute("prompt", prompt);
%>
<foo other_attributes enabled= "<%=prompt>"/>
will throw an error. (to do this you would have to specify rtexpr value of
this attribute to true)
For the above to work, your tag should be coded as shown below
private boolean enabled = false;
//note rtexpr value will always be Strings
//container does not provide auto conversions
public void setEnabled(String enabled) {
     this.enabled = new Boolean(enabled).booleanValue();
}cheers,
ram.