export ANT_HOME=/path/to/apache-ant
export CATALINA_HOME=/path/to/apache-tomcat
export JAVA_HOME=/path/to/jdk8
export PATH=$ANT_HOME/bin:$JAVA_HOME/bin:$PATH

ant clean war

First, install the PV Web Socket, which must be available on the same Tomcat instance.

Set the following environment variables, for example in $CATALINA_HOME/bin/setenv.sh:

• DBWR1, DBWR2, ...: URLs of displays to suggest on the start page.

Place dbwr.war in $CATALINA_HOME/webapps

Open the main page of the running instance for explanation of URLs used to open displays. Assuming Tomcat on localhost:8080, open

http://localhost:8080/dbwr

The following widget types and features have been implemented with basic functionality:

• Label
• Rectangle
• Ellipse
• Arc
• Polyline
• Polygon
• Text Update
• Text Input (can write)
• Text formatting (precision, units, enum labels)
• LED
• Multi-State LED
• Action Button to open display or web link
• Action Button to write value to PV
• Combo
• Group with group border
• Embedded Displays
• Tabs
• XYPlot
• Image, runtime options to change scaling and color map
• Macro support
• Alarm-sensitive border based on PV
• Limited Rule support: Color of rect/circle/label, visibility
• Caching

In principle, the PV Web Socket supports both Channel Access and PV Access, but so far all testing of the display builder web runtime has concentrated on Channel Access.

Each widget needs to derive from dbwr.widgets.Widget and register in widget.properties. The widget constructor parses the display file XML for the widget.

A static widget implements Widget.fillHTML() to create the static HTML content.

A dynamic widget registers Javascript in a static initializer that calls WidgetFactory.addJavaScript(). That Javascript can then register init or update methods via DisplayBuilderWebRuntime.prototype.widget_init_methods and DisplayBuilderWebRuntime.prototype.widget_update_methods.

Any widget with a data-pv attribute in its widget HTML will automatically subscribe to that PV. It should register a java script method in DisplayBuilderWebRuntime.prototype.widget_update_methods to handle the received PV updates.

PVs with multiple PVs can subscribe to additional PVs in their widget_init_methods.