KeyDefSyntax

Introduction

The view file is defined at runtime by the higher application. There is only one view active at a time.

It aims to:

• list accessible data for a data source
• organize data into a structure (that is human friendly or according the needs of the software)

Only keywords listed in the view will be available to the application. It restrict the number of keywords usable. Indeed the full list of keywords for a particular mapping, or all the ones defined in a concepts file would make a legion. Therefore method listing available data items of data source would be useless.

Below an example of a view file structured in a tree:

<!DOCTYPE data-def SYSTEM "view_file.dtd">
<data-def name="DATA_REDUCTION"> 
    <group key="detectors"> 
        <group key="detector"> 
            <item key="camera"/> 
            <item key="dark"/> 
            <item key="distance"/> 
            <item key="exposureTime"/> 
            <item key="shutterCloseDelay"/> 
            <item key="xBin"/> 
            <item key="yBin"/> 
        </group> 
        <group key="monitor"> 
            <item key="mi"/> 
            <item key="gain"/> 
            <item key="intensity_monitor"/>
        </group> 
        <group key="monochromator"> 
            <item key="lambda"/> 
            <item key="energy_mono"/> 
        </group> 
    </group> 
    <group key="data"> 
        <item key="images"/> 
        <item key="spectrums"/> 
        <item key="x_position"/> 
        <item key="y_position"/> 
    </group> 
    <group key="info"> 
        <item key="comments"/> 
    </group> 
</data-def>

It is also possible to have exactly the same list of available data items, but in a flat view:

<!DOCTYPE data-def SYSTEM "view_file.dtd">
<data-def name="DATA_REDUCTION"> 
    <item key="camera"/> 
    <item key="dark"/> 
    <item key="distance"/> 
    <item key="exposureTime"/> 
    <item key="shutterCloseDelay"/> 
    <item key="xBin"/> 
    <item key="yBin"/> 
    <item key="mi"/> 
    <item key="gain"/> 
    <item key="intensity_monitor"/>
    <item key="lambda"/> 
    <item key="energy_mono"/> 
    <item key="images"/> 
    <item key="spectrums"/> 
    <item key="x_position"/> 
    <item key="y_position"/> 
    <item key="comments"/> 
</data-def>

In the first view the distance item will be accessible using with the following calls in Java:

LogicalGroup group = dataset.getLogicalRoot();
IDataItem lambda = group.getDataItem( "detectors:detector:distance" );

In the second one the distance comes as following:

LogicalGroup group = dataset.getLogicalRoot();
IDataItem lambda = group.getDataItem( "distance" );