Composite pattern in LLD - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to declare the base component interface in the Composite pattern.

LLD

interface Component {
    void [1]();
}

Drag options to blanks, or click blank then click option'

AaddChild

Boperation

CremoveChild

DgetChild

Attempts:

3 left

💡 Hint

Common Mistakes

Choosing methods specific to composite like addChild instead of the common operation method.

The base component interface declares the common operation method that both leaf and composite classes implement.

2fill in blank

medium

Complete the code to add a child component in the Composite class.

LLD

class Composite implements Component {
    private List<Component> children = new ArrayList<>();

    public void [1](Component component) {
        children.add(component);
    }

    public void operation() {
        for (Component child : children) {
            child.operation();
        }
    }
}

Drag options to blanks, or click blank then click option'

Aoperation

BremoveChild

CgetChild

DaddChild

Attempts:

3 left

💡 Hint

Common Mistakes

Using removeChild or getChild instead of addChild for adding components.

The Composite class manages child components by adding them with the addChild method.

3fill in blank

hard

Fix the error in the Leaf class operation method to correctly implement the Composite pattern.

LLD

class Leaf implements Component {
    public void [1]() {
        System.out.println("Leaf operation");
    }
}

Drag options to blanks, or click blank then click option'

AremoveChild

BaddChild

Coperation

DgetChild

Attempts:

3 left

💡 Hint

Common Mistakes

Using composite-specific methods like addChild in Leaf.

The Leaf class implements the operation method from the Component interface to perform its specific action.

4fill in blank

hard

Fill both blanks to define the Composite class constructor and initialize the children list.

LLD

class Composite implements Component {
    private List<Component> children;

    public Composite() {
        children = new [1]<>();
    }

    public void addChild(Component component) {
        children.[2](component);
    }
}

Drag options to blanks, or click blank then click option'

AArrayList

BLinkedList

Cadd

Dremove

Attempts:

3 left

💡 Hint

Common Mistakes

Using remove instead of add to add children.

Using LinkedList instead of ArrayList (both work but ArrayList is more common).

The Composite class initializes its children list with ArrayList and adds components using the add method.

5fill in blank

hard

Fill all three blanks to implement a recursive operation method in Composite that calls operation on all children.

LLD

class Composite implements Component {
    private List<Component> children = new ArrayList<>();

    public void operation() {
        for ([1] : children) {
            [2].[3]();
        }
    }
}

Drag options to blanks, or click blank then click option'

AComponent child

Bchild

Coperation

DComponent

Attempts:

3 left

💡 Hint

Common Mistakes

Using incorrect loop variable type or name.

Forgetting to call the operation method on the child.

The for-each loop iterates over each child component, calling its operation method recursively.