Chapter 31 - Create Your Point Discovery Preferences

In the previous chapters of today's lesson, you defined a point discovery parameters object, point discovery leaf, point discovery request, and a point discovery response. This chapter will tie all of these classes together so that the developer driver's point manager can use them to discover the data points available on a field-device.

NOTE: This class is similar to the device discovery preferences class from yesterday's lesson.

Create a class named BYourDriverPointDiscoveryPreferences that extends BDdfAutoDiscoveryPreferences. Create this in the package com.yourCompany.yourDriver.discover.

To do this, create a text file named BYourDriverPointDiscoveryPreferences.java in the jarFileName/src/com/yourCompany/yourDriver/discover folder. Inside the text file, start with the following text:

package com.yourCompany.yourDriver.discover;

import com.tridium.ddf.identify.*;
import com.tridium.ddf.discover.auto.*;

import com.yourCompany.yourDriver.identify.*;

import javax.baja.sys.*;

public class BYourDriverPointDiscoveryPreferences
  extends BDdfAutoDiscoveryPreferences
{
  /*-
  class BYourDriverPointDiscoveryPreferences
  {
    properties
    {
    }
  }
  -*/
}

In the slotomatic properties section, redefine the following properties:

timeOut

Specify the default amount of time that your driver should wait after transmitting your point discovery request before timing out.

retryCount

Specify the default number of retries that your driver should attempt after a request times-out (before giving up on that particular request).

NOTE: Sometimes during a discovery process it could be helpful to specify shorter time-outs and less retries so that the entire point discovery process can complete sooner.

min

Specify the default to be a copy of whatever your point discovery parameters class returns from its getFirst method (or whatever your read request parameters class returns from its getFirst method, if you chose to have it serve in the discovery process).

max

Specify the default to be a copy of whatever your point discovery params class returns from its getLast method (or whatever your read request parameters class returns from its getLast method, if you chose to have it serve in the discovery process).

NOTE: Your min and max properties will be instances of the read request id if you re-use your read request as the discovery request. If not, your min and max will be instances of the BYourDriverPointDiscoverParams object that you created during today's lesson.

doNotAskAgain (optional)

Declare the default value as True if you do not want the integrator to receive a special prompt when he or she clicks the Discover button on the device manager. If you set this to true then the discovery process will automatically loop from the min to the max that you also specify here. Once you finish today's lesson, we encourage you to try this both ways and decide which way makes the most sense for your driver.

Please use the following source as a guide:

package com.yourCompany.yourDriver.discover;

import com.tridium.ddf.identify.*;
import com.tridium.ddf.discover.auto.*;

import com.yourCompany.yourDriver.identify.*;

import javax.baja.sys.*;

public class BYourDriverPointDiscoveryPreferences
  extends BDdfAutoDiscoveryPreferences
{
  /*-
  class BYourDriverPointDiscoveryPreferences
  {
    properties
    {
      timeout : BRelTime
        -- This is the amount of time to wait per field-bus request before timing out
        default{[BRelTime.makeSeconds(3)]}
        slotfacets{[BFacets.make(BFacets.make(BFacets.SHOW_MILLISECONDS,BBoolean.TRUE),
                                 BFacets.MIN,BRelTime.make(0))]}
      retryCount : int
        -- This is the number of discovery field-message retransmissions
        -- per request.
        default{[1]}
        slotfacets{[BFacets.make(BFacets.MIN,BInteger.make(0))]}
      min : BDdfIdParams
        -- This is the id of the lowest data point for your driver to attempt to
        -- learn by default
        default{[(BDdfIdParams)new BTestDriverReadParams().getFirst()]}
      max : BDdfIdParams
        -- This is the id of the highest point for your driver to attempt to
        -- learn by default
        default{[(BDdfIdParams)new BTestDriverReadParams().getLast()]}
    }
  }
  -*/
}

Redefine the discoveryPreferences property on the BYourDriverPointDeviceExt class that you created back during the lesson for day 2. Specify the default value to be an instance of BYourDriverPointDiscoveryPreferences.

NOTE: Please also add statements to import com.yourCompany.yourDriver.discover.*; and com.tridium.ddf.discover.*;

package com.yourCompany.yourDriver;

import javax.baja.sys.*;
import javax.baja.util.*;

import com.tridium.ddf.*;
import com.tridium.ddf.discover.*;

import com.yourCompany.yourDriver.point.*;
import com.yourCompany.yourDriver.discover.*;

public class BYourDriverPointDeviceExt
  extends BDdfPointDeviceExt
{
  /*-
  class BYourDriverPointDeviceExt
  {
    properties
    {
      discoveryPreferences : BDdfDiscoveryPreferences
        -- This saves the last set of discovery parameters that the user provided.
        -- It also allows the dev driver framework to automatically learn points
        flags{hidden}
        default{[ new BYourDriverPointDiscoveryPreferences()]}
    }
  }
  -*/
}

Run slotomatic and perform a full build on your driver (as described in Chapter 2).