Wrapper for some of standard Java collections with ability to add triggers that fire when the collection is modified. Each wrapper is called as Trigger + Java collection name. For example: TriggerCollection, TriggerList. Each trigger has 3 types of callbacks before, after and allow, and can be fired for all standard collection methods. Like before + standard method name. For now the following operations are supported:

1. beforeAdd/afterAdd/allowAdd

2. beforeAddAll/afterAddAll/allowAddAll

3. beforeRemove/afterRemove/allowRemove

4. beforeRemoveAll/afterRemoveAll/allowRemoveAll

5. beforeGet/afterGet

How to use

1. Build project with mvn clean package
2. Add jar file to your project

Keep track of collection modifying

List<Integer> sourceList = new ArrayList<>();

List<Integer> list = TriggerList.from(sourceList)
        .beforeAdd(valueToAdd -> someAction(valueToAdd))
        .afterRemove((valueToAdd, res) -> res ? doSmth() : doSmthElse())
        .build();

list.add(1);    // someAction(1) is called
list.add(5);    // someAction(5) is called
list.remove(3); // doSmthElse() is called

Prevent some of operation

List<Integer> sourceList = new ArrayList<>();
Predicate<Integer> predicate = integer -> integer < 5;

List<Integer> list = TriggerList.from(sourceList)
        .allowAdd(predicate)    // allow adding integers less than 5 only
        .build();

list.add(4);
list.add(6);

list.size(); // 1