Design Widget PalettemediumDesign Widget Palette
A UI builder keeps a palette of named widgets. Labels and buttons are leaves, panels hold other widgets, and a designer duplicates any of them by copying. A copied panel has to be a separate tree all the way down.
Label, Button, Panel and WidgetPalette are provided in the starter code. Implement only the widget contract and the three clone methods: declare Widget with render() and clone() (IWidget in C#) and complete Label.clone(), Button.clone() and Panel.clone().
The provided classes work like this:
Label(text)hassetText(text)and renders as"Label(Hello)".Button(caption)renders as"Button[OK]".Panel(title)hasadd(child),childCount()andchild(index), and renders as"Panel<Login>{Label(Hello), Button[OK]}"with its children in order, or"Panel<Login>{}"when empty.
Panel.clone() must return a new panel with the same title whose children are clones of the original children, obtained through the contract rather than by checking each child's kind.
The provided WidgetPalette behaves as follows:
WidgetPalette()starts empty.boolean createLabel(String name, String text),boolean createButton(String name, String caption)andboolean createPanel(String name, String title)store a new widget undername, or returnfalsefor an empty or taken name.boolean addToPanel(String panel, String child)adds the named child object itself to the named panel. It returnsfalsewhen either name is unknown, the first is not a panel, or both name the same widget. The same child may be added more than once.boolean copyWidget(String source, String target)clones the source and stores the copy undertarget, or returnsfalsefor an unknown source or a taken target.boolean setLabelText(String name, String text)changes a label's text, or returnsfalsewhen the name is not a label.boolean setPanelLabelText(String panel, int index, String text)changes the text of the label at that index inside the panel, or returnsfalsewhen the panel is unknown, the index is outside its children, or that child is not a label.String render(String name)returns the widget's rendering, or"MISSING".int widgetCount()returns how many named widgets exist.
The tests call the provided WidgetPalette; your work should be confined to the contract and the three clone methods.
Example 1:
Input:
Output:
Explanation: The copied panel holds a copy of the label. Changing that copy's text does not reach the original panel's label.
Example 2:
Input:
Output:
Explanation: The original outer panel still holds the original label, so editing it shows through. The copy was cloned all the way down and keeps the old text.
Constraints
0 <= name.length, text.length, caption.length, title.length <= 20-1 <= index <= 10- A panel nests at most
3levels deep. - At most
100calls in total are made across all methods.
Starter Code
Declare the Widget contract and complete the three clone() methods. Everything else in the three classes and all of WidgetPalette is provided and must not be modified.
How the design is graded
needs 7/10 to pass- The contract carries the copy
Full marks when `Widget` declares both `render` and `clone`, so the palette can copy any widget without knowing its kind. Lose points heavily when the palette or the panel checks a widget's type to copy it.
- The composite clones its children polymorphically
Full marks when `Panel.clone` builds a new panel and adds `child.clone()` for every child, so nested panels are copied all the way down and editing a label inside the copy leaves the original untouched. Lose points heavily when the new panel holds the original child objects.
- Leaves copy their own state
Full marks when `Label.clone` and `Button.clone` return new objects with the same text or caption. Lose points for printing to stdout.
Passing every test is not enough on its own. A submission is accepted only when the design also clears the bar.
| Call | Returns |
|---|---|
| new WidgetPalette() | null |
| createLabel("title", "Hello") | true |
| createButton("ok", "OK") | true |
| createPanel("form", "Login") | true |
| addToPanel("form", "title") | true |
| addToPanel("form", "ok") | true |
| copyWidget("form", "form2") | true |
| setPanelLabelText("form2", 0, "Bye") | true |
| render("form") | "Panel<Login>{Label(Hello), Button[OK]}" |
| render("form2") | "Panel<Login>{Label(Bye), Button[OK]}" |
The copied panel holds a copy of the label. Changing that copy's text does not reach the original panel's label.
Run checks these cases. Submit also runs a larger hidden set.