Wood J. Object-Oriented Programming with ABAP Objects

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Debugging Objects Using the Classic ABAP Debugger

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Figure A.2 Displaying the Attributes of an Object/Class

4. In the OBJECT display mode, you can edit individual primitive attributes by dou-

ble-clicking their names in the ATTRIBUTES/INTERFACES column. Similarly, you

can edit complex types by drilling into structures, internal tables, and embed-

ded objects.

5. You also can filter the display to specific types of attributes. For example, in Fig-

ure A.2, notice that both the static and instance attributes are displayed for an

object of type CL_SALV_TABLE. YOU can also filter attributes based on visibility

section assignment (e.g.. public, private, or protected).

6. Finally, if the class of the object in question implements an interface, you can

filter the attribute list to just those fields defined within the interface.

335

A | Debugging Objects

A.1.2 Tracing Through Methods

The process of tracing method logic is no different from tracing through a subrou-

tine or function module. Prior to a method invocation, you can select the SINGLE

STEP button to debug the method's implementation code. Inside the method, you

can continue to step into or step over individual lines of code as usual.

Similarly, if you want to exit from the method and resume debugging after the

method call, you can select the RETURN button. Of course, if you want to step over

the method implementation entirely, you can select the EXECUTE button to exe-

cute the method.

One thing to note is that constructor methods do not behave in the same way as

normal methods in the debugger. Ifyou step into the

CREATE OBJECT

statement,

the debugger will begin tracing through the constructor method. This is not the

case, however, with class constructors. Here, you must explicitly set a breakpoint

to debug the class constructor logic.

A.1.3 Displaying Events and Event Handler Methods

To display the registered events for an object/class:

1. Open the OBJECT display mode in the debugger.

2. Click on the EVENTS button to switch from object mode to events mode (see Fig-

ure A.3).

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Figure A.3 Displaying the Registered Events for an Object — Part 1

336

Debugging Objects Using the Classic ABAP Debugger

3. This view shows you all of the events defined for the object/class as well as any

registered handling objects for the events. You can navigate to the objects

shown in the HANDLING OBJECT column to set breakpoints in the event handler

methods to debug event handling scenarios. This can be sometimes useful in

frameworks when you are not real clear about where event handlers are regis-

tered, and so on.

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Figure A.4 Displaying the Registered Events for an Object — Part 2

A.1.4 Viewing Reference Assignments for an Object

You may encounter situations where an object is manipulated in ways that you

didn't expect. Here, it is possible that more than one reference to the object

exists. To view reference assignments for an object:

1. You can identify the set of references to an object by selecting GOTO • SYSTEM •

FIND REFERENCE in the menu area.

2. This menu option opens a dialog box showing you all of the references to the

object in question in the system (see Figure A.5). For instance, you can see that

337

A | Debugging Objects

the object of type CL_SALV_TABLE has four references, including the attribute

grid from class

cl_query_ctrl as well as the kernel reference.

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A.1.5 Troubleshooting Class-Based Exceptions

Whenever a statement triggers an exception during a debugging session, the

ABAP debugger traces the exception propagation process back to the exception

handler block that captures the exception — assuming there was one. Often, you

will encounter debugging scenarios where a developer chose not to capture the

exception situation in an exception object. This information can be crucial for

debugging complex exception situations. Therefore, you can modify the debug-

ger session settings to dynamically generate an exception object that you can use

to troubleshoot an error. To configure this setting, follow these steps:

1. Select the SETTINGS display mode, and click on the ALWAYS CREATE EXCEPTION

OBJECT checkbox (see Figure A.6).

2. After the exception is triggered, the cursor is placed at the beginning of the

CATCH block defined to handle the exception. If this CATCH block is not defined

using the INTO addition, then you can display the exception object by clicking

on the DISPLAY EXCEPTION OBJECT button (see Figure A.7). Otherwise, you can

double-click on the exception object reference just as you would for any nor-

mal object reference variable.

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Debugging Objects Using the Classic ABAP Debugger I A.1

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339

A | Debugging Objects

3. The exception object is displayed in the OBJECT display mode just like any other

object type. Here, you can trace the exception chain via the PREVIOUS attribute

in addition to any custom attributes that further define the exception situation

(sec Figure A.8).

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A.2 Debugging Objects Using the New ABAP Debugger

In most respects, the process of debugging objects in the New ABAP Debugger is

quite similar to the process of debugging objects in the Classic ABAP Debugger.

The primary difference from a functional perspective is in the layout of the

OBJECT display area. Context-sensitive access to this view is provided in all of the

various variable display sections within the debugger window. For example, by

double-clicking the object ID in the VALUE column shown in Figure A.9, you are

taken to the OBJECT display shown in Figure A.10.

340

Debugging Objects Using the New ABAP Debugger

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A | Debugging Objects

As you can see in Figure A.10, the OBJECT display in the New ABAP Debugger is

much more streamlined. Here, by default, you can see the attributes of the object/

class in question arranged hierarchically according to the inheritance hierarchy.

You can turn this feature off by selecting the SUPERCLASSES ON/OFF button directly

above the attribute display. Events and their registered event handler methods

are displayed using the EVENTS button. References to the object in question can be

viewed using the DISPLAY REFERENCES button.

In addition to all of the standard features carried over from the Classic ABAP

Debugger, the New ABAP Debugger also provides a function to display the inher-

itance hierarchy of a given object at runtime. This function can be accessed by

clicking on the DISPLAY INHERITANCE HIERARCHY button. Figure A.11 shows the

INHERITANCE RELATIONSHIP view for an object of type

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342

B The Author

James Wood is the founder and principal consultant of

I Bowdark Consulting, Inc., an SAP NetWeaver consulting

I and training organization. With more than seven years of

W*^ I experience as a software engineer, James specializes in cus-

I torn development in the areas of ABAP Objects, Java/J2EE,

SAP NetWeaver Process Integration, and the SAP

^^H^^^Hj NetWeaver Portal.

Before starting Bowdark Consulting. Inc. in 2006, James was

an SAP NetWeaver consultant for SAP America, Inc. and

IBM Corporation where he was involved in multiple SAP implementations. He

holds a master's degree in software engineering from Texas Tech University. To

learn more about James and the book, please check out his website at http://

www. bowda rkconsulting. com.

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