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NetUI Tag Library Overview

NetUI Tag Library Overview

This topic provides an overview of the NetUI JSP tag libraries. NetUI provides three tag libraries, the core HTML tags, the data grid tags and a simple set of template tags.

Tag Library URIPrefixDescription
http://beehive.apache.org/netui/tags-html-1.0netui This is the primary tag library supporting HTML, including the form controls. It provides a number of features, used throughout the tag libraries, such as error reporting and base tags. In addition, it contains the Tree support.
http://beehive.apache.org/netui/tags-databinding-1.0netui-data This tag library provides binding to relational data, providing the Data Grid. The feature spans uses from simple tables, to sortable, filterable, pageable and updateable grids.
http://beehive.apache.org/netui/tags-template-1.0netui-template This tag library provides a very simple templating facility, allowing common elements such as headers, footers, etc.

The prefix is the prefix used within the documentation set and obviously can be changed.

In a typical JSP, the following lines would be used to include each of the NetUI tag libraries:

<%@ taglib uri="http://beehive.apache.org/netui/tags-html-1.0" prefix="netui"%>
<%@ taglib uri="http://beehive.apache.org/netui/tags-databinding-1.0" prefix="netui-data"%>
<%@ taglib uri="http://beehive.apache.org/netui/tags-template-1.0" prefix="netui-template"%>

For more information on JSPs with NetUI see the JSP Files topic. In particular, there is a very simple template providing a starting point for developing NetUI enabled JSPs.

The NetUI tags support binding values from implicit object to attributes through the JSP 2.0 Expression Language (EL). This support is for read-only data. In addition, many tags support read-write access to implicit objects. This support is almost always done through the dataSource attribute on the tags. In addition, there are a number of binding contexts introduced to allow binding to page flows and other NetUI implicit objects. For more information on data binding see the Data binding to NetUI Implicit Objects topic.

Runtime Error Reporting

The tag libraries report runtime errors in a common way. In the page fragment below, a set of anchors have invalid attribute values. There is an error reported where the tag would normally have rendered HTML. In addition, there is a table rendered at the end of the document that contains the details of the errors. In many cases, runtime errors in the tags result in the tag reporting an error and rendering continues on. This means that multiple errors will be reported. In addition, many tags will report multiple errors. Typically, errors wouldn't occur in production because they would be fixed during development. The error reporting is intended to make developing new pages easier by making errors obvious.

Runtime Errors Reported in a Rendered Page

Runtime Errors produced by the tags

Core HTML Tags

The core HTML tag library provides the core HTML elements. These include both the HTML structure and the HTML form controls. In addition, the tags provide a number of core features that are used by all of the NetUI tag libraries.

The HTML tags have a simple and expected mapping to the HTML elements that they generate. See the HTML to NetUI Tag Mapping for details. In addition, the HTML controls, called form controls in this document, have additional details in the NetUI Form Control Tags topic.

The HTML tags can support multiple versions of the HTML specifications, including HTML 4.01 and XHTML 1.0 Transitional. The default format is specified for a WebApp and may be overridden for an individual document. For more information see the HTLM and XHTML Support topic.

NetUI provides the ability to build pages that are part of a larger composite page such as a portal. Part of this support is the ability to scope the HTML id attributes. In order to allow client side JavaScript to run, the core tags provide support for accessing the generated id and name values based upon a local name. For more information on JavaScript support see the Tags Support for JavaScript topic.

Finally, the core tags provides a set of tags and classes that can be used to build complex tree representations. See the Tree Tags topic for information on creating trees.

Data Tags

The NetUI data tag library provides tags that render complex, high-level HTML markup in a page or that support data binding in JSPs. The library supports a range of features from simple tables rendered with the repeater to complex data grids rendered with the data grid tag set. The data grid includes support for sortable columns, filtering, paging and updatable grids. Styles can be applied to the grids to customize their presentation. For more information on the data grid see Beehive NetUI Data Grids. For more information on the repeater tags, see Repeating JSP Tags.

Template Tags

The template tags represent a very simple templating system. The tags allow for a very simple template page to be created. Content pages then include their template to form the resulting rendered page. The content pages are written as sections of content that are inserted into defined points inside the template. For more information on the template tags see the NetUI Template Tags topic.