CODEWITHSUNDEEP
javastaticaopaspectj
ashishakp
ashishakp

Reputation: 121

How to intercept a static property in java class using AspectJ?

In the following code snippet I need to execute some logic whenever the property myList is accessed. Is it possible? 

public class Test {
    public static List<String> myList = new ArrayList();

    public static void addData(){
        myList.add("foo");
        myList.add("bar");
    }
    public static void removeData(){
        if(myList.size() > 0){
            myList.remove(0);
        }
    }
    public static void displayData(){
        for (String data : myList) {
            System.out.println("data : "+data);
        }
    }

    public static void main(String[] args) {
        addData();
        displayData();
        removeData();
        displayData();
    }
}

Upvotes: 4

Views: 494

Answers (2)

Daniel Wisehart
Daniel Wisehart

Reputation: 1509

Your question is simple enough that I do not know if I understand it. From what you have said a very small adjustment answers it.

public class Test {
    private static List<String> myList = new ArrayList();

    public static void addData() {
        myListAccessLogic();
        myList.add("foo");

        myListAccessLogic();
        myList.add("bar");
    }
    public static void removeData() {
        myListAccessLogic();
        if(myList.size() > 0) {

            myListAccessLogic();
            myList.remove(0);
        }
    }
    public static void displayData() {
        myListAccessLogic();
        for (String data : myList) {

            myListAccessLogic();
            System.out.println("data : "+data);
        }
    }

    public static void main(String[] args) {
        addData();
        displayData();
        removeData();
        displayData();
    }
}

Upvotes: 0

XGouchet
XGouchet

Reputation: 10203

You can weave code Before/After/Around any access to your field using the following pointcuts : 

@Aspect
public class TestAccessorsAspect {
    @Pointcut("get(java.util.List com.sample.Test.myList)")
    public void readMyList(){}

    @Pointcut("set(java.util.List com.sample.Test.myList)")
    public void writeMyList(){}
}

in .aj syntax, this might look like this : 

public aspect TestAccessorsAspect {

    pointcut readMyList() : get(java.util.List com.sample.Test.myList);   

    pointcut writeMyList() : set(java.util.List com.sample.Test.myList);   
}

Whenever those field are accessed for reading (resp. writing), those pointcuts are going to be triggered.

Upvotes: 2

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