CollectionContainer

setItems() - sets a collection of entities to the container.

getItems() - returns an immutable list of entities stored in the container. Use this method to iterate over the collection, to get a stream or to get an instance by its position in the list. If you need to get an entity instance by its id, use getItem(entityId). For example:

@ViewComponent
private CollectionContainer<Department> departmentsDc;

private Optional<Department> findByName(String name) {
    return departmentsDc.getItems().stream()
            .filter(department -> Objects.equals(department.getName(), name))
            .findFirst();
}

getMutableItems() - returns a mutable list of entities stored in the container. All list changes caused by the add(), addAll(), remove(), removeAll(), set(), clear() methods produce CollectionChangeEvent, so subscribed visual components will update accordingly. For example:

@ViewComponent
private CollectionContainer<Department> departmentsDc;

private void createDepartment() {
    Department department = metadata.create(Department.class);
    department.setName("Operations");
    departmentsDc.getMutableItems().add(department);
}

setItem() - sets the current item for this container. If the provided item is not null, it must exist in the collection. The method sends ItemChangeEvent.

@ViewComponent
private DataGrid<Department> departmentsTable;

@ViewComponent
private CollectionContainer<Department> departmentsDc;

private void selectFirstRow() {
    departmentsTable.getSelectionModel()
            .select(departmentsDc.getItems().get(0));
}

getItem() - overrides the method of InstanceContainer and returns the current item. If the current item is not set, the method throws an exception. Use this method when you are sure that the current item has been set for the container, then you don’t have to check the returned value for null.

getItemOrNull() - overrides the method of InstanceContainer and returns the current item. If the current item is not set, this method returns null. Please always check the returned value for null before using it.

getItemIndex(entityId) - returns the position of an instance with the given id in the list returned by the getItems() and getMutableItems() methods. This method accepts Object and you can pass either id or the entity instance itself. The container implementation maintains a map of ids to indexes, so the method works fast even on large lists.

getItem(entityId) - returns an instance from the collection by its id. It’s a shortcut method that first obtains the instance position using getItemIndex(entityId) and then returns the instance from the list using getItems().get(index). The method throws an exception if the instance with the specified id doesn’t exist in the collection.

getItemOrNull(entityId) - same as getItem(entityId) but returns null if the instance with the specified id doesn’t exist in the collection. Always check the returned value for null before using it.

containsItem(entityId) - returns true if an instance with the specified id exists in the collection. It’s a shortcut method that uses getItemIndex(entityId) under the hood.

replaceItem(entity) - if the item with the same id exists in the container, it is replaced with the given instance. If not, the given instance is added to the items list. The method sends CollectionChangeEvent of the SET_ITEM or ADD_ITEMS type depending on what has been done.

setSorter() - sets the given sorter for this container. A standard implementation of the Sorter interface is CollectionContainerSorter. It is set by the framework automatically when the container is associated with a loader. You can provide your own implementation if needed.

getSorter() - returns the sorter currently set for this container.