CODEWITHSUNDEEP
javastack-trace
Karim Oukara
Karim Oukara

Reputation: 2706

how do we know which method (java.class) has called the current one

Example: If I have two classes: A and B. both class can call a method in C (example: the init() method)

From C, how do we know where the call is from (from Class A or Class B) ?

Upvotes: 4

Views: 2443

Answers (4)

Karim Oukara
Karim Oukara

Reputation: 2706

I found an easier solution (for me :D )

public <T> void init(Class<T> clazz) {
     if (!clazz.getSimpleName().equals("MyClassName")) {
          // do something
     }else{
          // do something
     }
}

Upvotes: 0

rolve
rolve

Reputation: 10218

To do it right, you should provide C's method with that information, for example via an enum or class parameter:

public void init(Object otherArg, Class<?> caller) {
    ...
}

or

public void init(Object otherArg, CallerEnum caller) {
    ...
}

But if you don't care, there is another way using the stack trace. Have a look at Get current stack trace in Java and use the second StackTraceElement from the top of the stack to get the method that called the current one.

Upvotes: 3

sohel khalifa
sohel khalifa

Reputation: 5588

This may be useful:

StackTraceElement[] stackTraceElements = Thread.currentThread().getStackTrace();

  • you can use this to get the stack trace of the current thread in a StackTraceElement array where the first element of the array is the most recent method invocation sequence on the stack

  • provided the returned array is of non-zero length. StackTraceElement has methods like getClassName, getMethodName, etc., which one can use to find the caller class name or method name.

Upvotes: 3

urir
urir

Reputation: 2025

Taken from somewhere of the web...

private static final int CLIENT_CODE_STACK_INDEX;

static {
    // Finds out the index of "this code" in the returned stack trace - funny but it differs in JDK 1.5 and 1.6
    int i = 0;
    for (StackTraceElement ste : Thread.currentThread().getStackTrace()) {
        i++;
        if (ste.getClassName().equals(MyClass.class.getName())) {
            break;
        }
    }
    CLIENT_CODE_STACK_INDEX = i;
}

public static String getCurrentMethodName() {
    return Thread.currentThread().getStackTrace()[CLIENT_CODE_STACK_INDEX].getMethodName();
}
public static String getCallerMethodName() {
    return Thread.currentThread().getStackTrace()[CLIENT_CODE_STACK_INDEX+1].getMethodName();
}

Upvotes: 1

Related Questions