Accessors

Traditionally, custom tags are used to access logic and data from within JSP pages. With the integration of the expression language (EL) into the JSP 2.0 standard, many custom tags have become obsolete. Consequent usage of EL expressions in combination with the Java Standard Tag Library (JSTL) may now lead to very nice JSP code. Calyxo supports this approach by providing so-called accessors, that present themselves as a hierarchy of beans and maps, ready to be used in EL expressions.

Beside implementing various concrete accessors, the Calyxo Base component provides the Access API, which may be used by application programmers to contribute their own accessors.

Please refer to the Accessors reference to explore the accessors provided by Calyxo Base.

Using Accessors

The tree of accessors is instantiated and installed into request scope using the <base:access> tag, like in

<jsp:root xmlns:jsp="http://java.sun.com/JSP/Page" version="2.0"
  xmlns:base="http://calyxo.odysseus.de/jsp/base">
    ...
    <base:access var="calyxo"/>
    ...
</jsp:root>

By convention, we use calyxo to denote the root.

Now, that the accessors have been installed into request scope at attribute calyxo, JSP EL expression of the form calyxo.* are used to select and invoke accessors.

As an example, to take property foo from the bean at attribute mybean in module scope, you would use an expressions like ${calyxo.base.module.attribute['mybean'].foo}.