Question

I am trying to write a recursive method that searches through a list of IData objects and returns a specific implementation. The list contains objects that implements the interface IData.

There are two implementations of this interface:

1) DataImpl

2) DataContainerImpl

The DataContainerImpl has a:

 List<IData> children;

so it can hold nested DataContainerImpl elements or just plain DataImpl’s. Here is what I do:

  public static DataContainerImpl findDataContainerWithName(Collection<IData> elements, String name) {
    for (IData  element : elements) {
      if (element instanceof DataContainerImpl) {
        DataContainerImpl container = (DataContainerImpl) element;
        if (container.getName().equals(name)) {
          return container ;
        }

       container = findDataContainerWithName(container.getChildren(), name);
       if (container != null) {
         return container ;
       }
      }
    }
    return null;
  }

Answer 1

Not exactly sure what you are doing here, but calling “findContainerByName()” recursively without a “return” in front of it wont do you any good.

The recursive call will return , but then the call will drop to the bottom and return null.

For example, if your list contained just 1 DataContainerImpl whose name did not match the name you called the method with, but it contains inside it a list with again just 1 DataImpl, you will still get null back. Is this what you want?