Re: Custom Tags in JSP and the ID attribute

"Mize-ze" <>
30 Oct 2006 06:04:46 -0800
I guess that my problem is that the tree attribute in condition tag is
treated by me as a TreeTag object in the setTree method:

 public void setTree(Tags.TreeTag tree) {
         this.tree = tree;
         this.treeObj = tree.getTreeObject();

While from the JSP point of view I am transferring a string.
Is that my problem? how can I send a treeTag or better yet a real


Mize-ze wrote:

I've tried something else, my JSP file looks something like that now:

<aot:tree id="tree" />
<aot:condition id="1" tree="tree" operator="eq" property="cpu-time"

I assume that the id attribute in aot:tree relates to the TagSupport
object, Which I called treeTag.
The condition tag then gets the reference to the TreeTag which holds
the Tree object itself.
However I could not get it to work.
Any Ideas?

TreeTag:: public int doStartTag ()
        this.treeObject = new AndOrTree();
        return SKIP_BODY;

ConditionTag:: public void setTree(Tags.TreeTag tree) {
        this.tree = tree;
        this.treeObj = tree.getTreeObject();

Then the ConditionTag::doStartTag uses the treeObj!
Makes sense?

steen wrote:

you could do a little something like this :

public class TreeTag extends javax.servlet.jsp.tagext.TagSupport {
  private AndOrTree tree = new AndOrTree();

  public AndOrTree getAndOrTree() {
    return tree;

and then in your sub-tags, you can do this whenever you need the tree :
  ((TreeTag) getParent()).getAndOrTree()

but this requires that your condition and accumulator tags always are
inside a treetag.
  <aot:condition .... />
  <aot:accumulator ... />


Mize-ze wrote:


I want to add a custom tag to my application so it will be more
Let's say I have some tree like structure that can be used like that in
a scriptlet:

 AndOrTree t = new AndOrTree();

The addCondition and addAccumulator functions take as a first argument
an "id"
this id uniquelly identifies the node in the tree.

The addAccumulator takes two "ids" of nodes, which will be the new
Node's sons.

So basically when I create a new "Accumulator" with
t.addAccumulator("5","3","4",AndOrTree.ACCUMULATOR.OR); I create a new
Node with identifier 5 that is a parent of nodes 3 and 4.

Now, I want to keep the same functionallity under customer Tags.
In my vision, it should look something like that:

<aot:condition id="1" operator="<" property="size" value="8" >
<aot:condition id="2" operator="<" property="cpu-time" value="85" >
<aot:accumulator id="3" name1="1" name2="2" ...>

Since there is a Tree out there, I guess I should also implement a tag
that initializes the tree
The tree should also be transferred to other tags for reference, so it
should be something like that:

<aot:tree id="myTree">
<aot:condition tree="myTree" id="1" operator="<" property="size"
value="8" >
<aot:condition tree="myTree" id="2" operator="<" property="cpu-time"
value="85" >
<aot:accumulator tree="myTree" id="3" name1="1" name2="2" ...>

I "extended" TagSupport and did the previous bit of
inside the doStartTag () function.
My problem is with the TreeTag, How can I implement and extended
TagSupport that will have a reference to a AndOrTree that I can later
set as a member of the other Tag classes?

My tag handlers looks like that:
public class ConditionTag extends javax.servlet.jsp.tagext.TagSupport{

     //For the TLD calls;
    private String property;
    private String operator;
    private String value;
    private AndOrTree tree;

    /** Creates a new instance of ConditionTag */
    public ConditionTag() {
       public void setOperator(String operator) {
        this.operator = operator;

    public String getOperator() {
        return operator;

    public String getValue() {
        return value;

    public String getProperty() {
        return property;

    public void setValue(String value) {
        this.value = value;

    public void setProperty(String property) { = property;

    public AndOrTree getTree() {
        return tree;

    public void setTree(AndOrTree tree) {
        this.tree = tree;

    public int doStartTag ()


        return SKIP_BODY;

   public int doEndTag()
        return EVAL_PAGE;


How should I implement the TreeTag class?

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