Time for action – finding the leak

It is necessary to know how many resources are allocated in order to know whether the leak has been plugged or not. Fortunately, SWT provides a mechanism to do this via the Display and the DeviceData class. Normally, this is done by a separate plug-in, but in this example, the ClockView will be modified to show this behavior.

1. At the start of the ClockView class's createPartControl method, add a call to obtain the number of allocated objects, via the DeviceData of the Display class:

   public void createPartControl(Composite parent) {
     Object[] objects = parent.getDisplay().getDeviceData().objects;

2. Iterate through the allocated objects, counting how many are instances of Color:

     int count = 0;
     for (int i = 0; i < objects.length; i++) {
       if (objects[i] instanceof Color) {
         count++;
       }
     }

3. Print the count to the standard error stream:

   System.err.println("There are " + count + " Color instances");

4. Now run the code in debug mode and show the Clock View...