../../AspectXLib/CodeInstrumentation/Base/aspects/TraceMethodEntry.ax
printf
instruction that
writes a message to the output device stating the name of the method and the name of the class
to which it belongs. In this example, the identification of the methods for which tracing is to
be performed (and which therefore must be modified by the aspect) is done "by name". This is
probably the simplest approach in AspectX.
This aspect defines four advices that describe four separate but related
changes. The first advice inserts the tracing code in the target methods. The second advice
inserts a new include
statement to include the stdio
library that is
required by the printf
method. The third advice modifies the comments of the
classes that are affected by the change to include a statement that the class code has been
automatically modified by an aspect program. The fourth advice modifies the comment of the
methods that are affected by the change to include a description of the type of change that has
been woven into the code.
This sample aspect program targets all methods called
fTwoParameter
.
Pointcuts | |
function | targetMethodImplementation |
Points to the implementations of the methods that must be modified | |
function_decl | targetMethodDeclaration |
Points to all declarations of the target methods | |
comment | targetMethodComment |
Points to the method comments that must be modified | |
class | targetClass |
Points to all classes that contain a target method | |
comment | targetClassComment |
Points to the class comments that must be modified | |
unit | targetImplementationUnit |
Points to all the units that contain implementations of methods that must be
modified | |
Advices | |
begin | insertTrace |
Insert the tracing instruction in the target methods | |
add | addInclude |
Add the #include statement for the stdio library | |
end | insertClassComment |
Add a comment at the end of the comment of the classes that are modified by other advices | |
end | insertMethodComment |
Add a comment at the end of the comment of the methods that are modified by other advices |
fTwoParameter
.
The implementation of the restriction relies on the
fact that in srcML the element name
contains two other name
subelements
where the first of them contains the class name and the second contains the name of the method.
Therefore to access the name of the method the following expression is used:
src:name/src:name[2]
.
If it were
desired to capture more than one target class, this could be done by modifying the XPath
expression in the constraint to include names whose class part matches several class names.
This pointcut only points to the method implementation. A second pointcut
(targetMethodDeclaration
) points to the method declarations.targetMethodImplementation
) but note that in srcML element
name
in a declaration file directly contains the method name.
Hence, the constraint in the pointcut does not need to use the
src:name/src:name[2]
expression.targetMethodDeclaration
pointcut. targetMethodDeclaration
pointcut targetClass
pointcut. Triplet: function begin codeFragment
Refers to global pointcut: function targetMethodImplementation
Triplet: unit add include
#include
statement for the stdio
library.
Inclusion of this library is necessary because the code that is woven into the target methods
calls the stdio function printf
. Note that the code to be added by this advice is
specified using the CDATA section because otherwise the braces around "stdio" would be
interpreted as xml braces by the XWeaver program.Refers to global pointcut: unit targetImplementationUnit
Triplet: comment end comment
Refers to global pointcut: comment targetClassComment
Triplet: comment end comment
Refers to global pointcut: comment targetMethodComment