Java 8 here. I have the following POJOs:
public interface HasPartNumber {
String getPartNumber();
}
@Getter
@Setter
public class InventoryItem implements HasPartNumber {
private String modelNumber;
private String description;
// lots of other fields here
@Override
public String getPartNumber() {
return this.modelNumber;
}
}
public class Inventory extends ArrayList<InventoryItem> {
// Inventory is just an alias of a list of InventoryItem
}
@Getter
@Setter
public class PriceItem implements HasPartNumber {
private String equipmentNumber;
// lots of other fields here
@Override
public String getPartNumber() {
return this.equipmentNumber;
}
}
public class PriceRoster extends ArrayList<PriceItem> {
// PriceRoster is just an alias of a list of PriceItem
}
I understand some of you may have an aversion to how I'm modeling Inventory and PriceRoster, but using the is-a and has-a golden rule, it is correct. An "inventory" is no more and no less than just a list of InventoryItems. Ditto for PriceRoster. And, the Domain-Driven Design community would probably agree that these are valid data models if it makes sense to a developer reading the code.
However, I am not married to this design. And so while my druthers would be to keep this data model above, if it truly is impossible to accomplish what I describe below without changing the data model, I'll be flexible.
I am trying to write a generic PartProcessor class that will iterate through lists of HasPartNumber impls and perform processing on them. My best attempt:
public class PartProcessor<PART_CONTAINER extends List<HasPartNumber>> {
public void process(PART_CONTAINER partContainer) {
partContainer.stream().forEach(part -> {
// Do something here
});
}
}
produces compilation errors when I go to instantiate the PartProcessor:
PartProcessor<Inventory> inventory = new PartProcessor<Inventory>();
The compiler errors I'm seeing are:
"Type parameter 'com.example.myapp.Inventory' is not within its bound; should implement 'java.util.List<com.example.myapp.HasPartNumber>'"
Any ideas what I can do to get my PartProcessor working generically on any list of HasPartNumbers impl, including Inventory and PriceRoster?
