Implement Your Instrumentation Logic

The iSDK provides a class called AGenericInterceptor, which must be subclassed with the desired custom interceptor logic.

The agent examines .jar files deployed to the agent's sdk-plugins directory and looks for classes that extend AGenericInterceptor. These classes must implement the required abstract methods.

One key method all interceptors must implement is the initializeRules method, which returns a list of objects that extend the IRule interface. These IRules represent where in the code you must apply a given interceptor (class name, method name, method params, and so on).

If interceptors need to perform reflection on any of the java objects used in the instrumented code, an interface, IReflector, is provided to facilitate such reflection at runtime.

Important Methods to Implement in AGenericInterceptor

• initializeRules - Returns a list of objects that describe where in the code the interceptor must be placed
• onMethodBegin - Any code in the body of this method is run before the execution of the instrumented method
• onMethodEnd - Any code in the body of this method is run after the execution of the instrumented method

These interceptors can be applied anywhere in the code, rather than just the beginning or end of a method. Also, they collect local variable information. Specific methods in the Rule builder, such as atLineNumber, atField, atLocalVariable, and so on only apply to this variety of iSDK interceptor.