public int doStartTag() throws JspException {
        super.setValue(new ArrayList<Attribute>());
        return super.doStartTag();
    }

    /**
     * PutListAttributeTag may not have any body, except for PutAttribute tags.
     *
     * @return <code>SKIP_BODY</code>.
     * @throws JspException if a JSP exception has occurred
     */
    public int doAfterBody() throws JspException {
        return (SKIP_BODY);
    }

    /**
     * Release the state of this put list by
     * clearing the contents of the list.
     */
    public void release() {
        super.setValue(null);
        super.release();
    }

    /**
     * Process nested &lg;putAttribute&gt; tag.
     * <p/>
     * Places the value of the nested tag within the
     * {@link org.apache.tiles.AttributeContext}.It is the responsibility
     * of the descendent to check security.  Tags extending
     * the {@link org.apache.tiles.jsp.taglib.ContainerTagSupport} will automatically provide
     * the appropriate security.
     *
     * @param nestedTag the put tag desciendent.
     */
    public void processNestedTag(AddAttributeTag nestedTag) {
        Attribute attribute = new Attribute(
            nestedTag.getValue(), nestedTag.getRole(),
            AttributeType.getType(nestedTag.getType()));

        this.addValue(attribute);
    }

    /**
     * Adds an attribute value to the list.
     *
     * @param attribute The attribute to add.
     */
    private void addValue(Attribute attribute) {
        this.getValue().add(attribute);
    }
}