Rendering (Stamping) the Table Data
The immediate children of an af:table component must all be af:column components. Each visible af:column component creates a separate column in the table.
The child components of each column display the data for each row in that column. The column does not create child components per row; instead, each child is repeatedly rendered (stamped) once per row.
Because of this stamping behavior, some components many not work inside the table. Any component that is pure output, with no behavior, will work without problems. ADF Faces input components work properly. Components that themselves support stamping are not supported, such as tables within a table.
As each row is stamped, the data for the current row is copied into a property that can be addressed using an EL expression. You specify the name to use for this property in the var property on the table. After the table has completed rendering, this property is removed or reverted back to its previous value.
In the example in the slide, the data for each row is referenced by using the variable row, which identifies the data to be displayed in the table. Each column displays the data for each row as defined by a particular attribute.