Conditional breakpoint by caller in Java eclipse

问题:

I am trying to track a change of a value using watchpoint in a Java program in Eclipse debugger. The class hierarchy is pretty complex and the value I am tracking is wrapped in container, which is used on many places.

To be more specific, there is a container SizeRequirement, which has a property minimum, which I am tracking. This class is used by many layout managers on many places for many components to define requirement for component's sizes. I need to catch exact call, where the value changes/is set for one specific layout manager and one specific component in it. Is it possible to filter breakpoints by caller? I will try to explain the problem using some abstract code:

class ValueContainer {
  public String value;
}

class A {

  private ValueContainer valueContainer;

  public A () {
    valueContainer = new ValueContainer();
    valueContainer.value = "setByA";
  }

}

class B {

  private ValueContainer valueContainer;

  public B () {
    valueContainer = new ValueContainer();
    valueContainer.value = "setByB";
  }

}

I set a watchpoint on value and I only want breakpoint to suspend only when the value is set by class A and ignore calls by B.

To make things worse, class SizeRequirement is part of swing library and is deeply integrated in code, so I cannot use inheritance to replace it by some child on some exact place where I want to track it.

EDIT

So this is what I used as conditional breakpoint condition. Believe or not, it works. :)

    StackTraceElement[] arr = Thread.currentThread().getStackTrace();
    boolean contains = false;
    for(StackTraceElement e : arr) {
        if (e.getClassName().contains("A")) {
            contains = true;
            break;
        }
    }

回答1:

It's pretty disgusting and probably slow, but you can use

Thread.currentThread().getStackTrace()[2].getClassName().contains("A")

as your breakpoint condition.

Based on this bug https://bugs.eclipse.org/bugs/show_bug.cgi?id=72961 I don't think Eclipse will support it directly

回答2:

Eclipse can do that. Create a breakpoint, then go into the Debug perspective and into the "Breakpoints" view. Select the breakpoint and

There you can say enable "Conditional" and select "Suspend when value changes"

You then have to enter your value in the field below, in your case probably "minimum".

Edit:

I just tried that and it didn't work as expected, but I've found another solution that might work:

data breakpoints in java/eclipse

In summary: Create a breakpoint in the line where your field is defined, it will become a watchpoint. In the "Breakpoint Properties" you can specify it to only suspend on change (the symbol on the margin will be a pen), not on access (symbol will be a pair of glasses).