程序代写代做代考 C graph The Composite Design Pattern

The Composite Design Pattern
EECS3311 A: Software Design Winter 2020
CHEN-WEI WANG
Motivating Problem (2)
Design for tree structures with whole-part hierarchies.
CHASSIS
CARD
CABINET CHASSIS
HARD_DRIVE
POWER_SUPPLY
DVD-CDROM
2
Challenge
: There are base and recursive modelling artifacts.
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Motivating Problem (1)
● Many manufactured systems, such as computer systems or stereo systems, are composed of individual components and sub-systems that contain components.
e.g., A computer system is composed of:
● Individualpiecesofequipment(harddrives,cd-romdrives)
Each equipment has properties : e.g., power consumption and cost.
● Compositessuchascabinets,busses,andchassis
Each cabinet contains various types of chassis, each of which in turn containing components (hard-drive, power-supply) and busses that contain cards.
● Design a system that will allow us to easily build systems and calculate their total cost and power consumption.
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Multiple Inheritance: Combining Abstractions (1)
A class may have two more parent classes.
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MI: Combining Abstractions (2.1)
Q: How do you design class(es) for nested windows?
Hints: height, width, xpos, ypos, change width, change height,
move, parent window, descendant windows, add child window
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MI: Name Clashes
In class C, feature foo inherited from ancestor class A clashes with feature foo inherited from ancestor class B.
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MI: Combining Abstractions (2)
A: Separating Graphical features and Hierarchical features
class RECTANGLE feature — Queries
width, height: REAL
xpos, ypos: REAL feature — Commands
make (w, h: REAL) change_width change_height move
end
class TREE[G] feature — Queries
descendants: ITERABLE[G] feature — Commands
add (c: G)
— Add a child ‘c‘.
end
test_window: BOOLEAN
local w1, w2, w3, w4: WINDOW do
create w1.make(8, 6) ; create w2.make(4, 3) create w3.make(1, 1) ; create w4.make(1, 1) w2.add(w4) ; w1.add(w2) ; w1.add(w3)
Result := w1.descendants.count = 2
class WINDOW inherit
RECTANGLE
TREE[WINDOW] end
end
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MI: Resolving Name Clashes
class C inherit
A rename foo as fog end
B rename foo as zoo end …
o.foo
o.fog
o.zoo
o: A
o: B
o: C
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✓×× ✓×× ×✓✓

Solution: The Composite Pattern Composite Architecture: Design (1.2)
●
● ●
Design : Categorize into base artifacts or recursive artifacts.
Programming :
Build a tree structure representing the whole-part hierarchy .
Runtime :
Allow clients to treat base objects (leafs) and recursive compositions (nodes) uniformly .
⇒ Polymorphism : leafs and nodes are “substitutable”. ⇒ Dynamic Binding : Different versions of the same
Q: Any flaw of this first design?
A: Two “composite” features defined at the EQUIPMENT level:
○ children: LIST[EQUIPMENT] ○ add(child: EQUIPMENT)
operation is applied on individual objects and composites. e.g., Given e: EQUIPMENT :
⇒ Inherited to all base equipments (e.g., HARD DRIVE) that do not apply to such features.
○ e.price may return the unit price of a DISK DRIVE.
○ e.price may sum prices of a CHASIS’ containing equipments.
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Composite Architecture: Design (1.1) Composite Architecture: Design (2.1)
e􏰢􏰋i􏰨􏰛e􏰐􏰅
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E􏰽􏰓I􏰹􏰸E􏰔􏰕*
chi􏰦d􏰆e􏰐+: LIST􏰑..􏰖
C􏰒􏰸􏰹􏰒􏰜I􏰕E􏰑􏰕􏰖*
􏰈􏰉a􏰅􏰋􏰆􏰉
chi􏰦d􏰆e􏰐: LIST􏰑􏰕􏰖 add_chi􏰦d(􏰏: 􏰕)
􏰉􏰐􏰎􏰋􏰆􏰉 chi􏰦d􏰆e􏰐􏰑chi􏰦d􏰆e􏰐.􏰏􏰇􏰋􏰐􏰅􏰖 = 􏰏
+ e+ CLIE􏰔􏰕
􏰈􏰉a􏰅􏰋􏰆􏰉
􏰨􏰆ice: REAL
􏰈􏰉a􏰅􏰋􏰆􏰉
add_chi􏰦d(􏰉: E􏰽􏰓I􏰹􏰸E􏰔􏰕)
􏰉􏰐􏰎􏰋􏰆􏰉 chi􏰦d􏰆e􏰐􏰑chi􏰦d􏰆e􏰐.􏰏􏰇􏰋􏰐􏰅􏰖 = 􏰉
e􏰢􏰋i􏰨􏰛e􏰐􏰅
+ CLIE􏰔􏰕
e+
E􏰽􏰓I􏰹􏰸E􏰔􏰕* 􏰨􏰆ice: REAL
chi􏰦d􏰆e􏰐+: LIST􏰑..􏰖
􏰈􏰉a􏰅􏰋􏰆􏰉
++*
DI􏰜K􏰪D􏰝I􏰺E
􏰺IDE􏰒􏰪CA􏰝D
C􏰒􏰸􏰹􏰒􏰜I􏰕E􏰪E􏰽􏰓I􏰹􏰸E􏰔􏰕
+++ CABI􏰔E􏰕 CHA􏰜􏰜I􏰜 B􏰓􏰜
++*
DI􏰜K􏰪D􏰝I􏰺E
􏰺IDE􏰒􏰪CA􏰝D
C􏰒􏰸􏰹􏰒􏰜I􏰕E􏰪E􏰽􏰓I􏰹􏰸E􏰔􏰕
+++ CABI􏰔E􏰕 CHA􏰜􏰜I􏰜 B􏰓􏰜
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Implementing the Composite Pattern (1)
deferred class
EQUIPMENT
feature
name: STRING
price: REAL — uniform access principle
end
class
CARD
inherit
EQUIPMENT
feature
make (n: STRING; p: REAL)
do
name := n
price := p — price is an attribute end
end
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Implementing the Composite Pattern (2.2)
class
COMPOSITE_EQUIPMENT
inherit
EQUIPMENT
COMPOSITE [EQUIPMENT] create
make
feature
make (n: STRING)
do name := n ; create children.make end price : REAL — price is a query
— Sum the net prices of all sub-equipments
do across
children as cursor loop
Result := Result + cursor.item.price — dynamic binding end
end end
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Implementing the Composite Pattern (2.1)
deferred class
COMPOSITE[T] feature
children: LINKED_LIST[T]
add (c: T) do
children.extend (c) — Polymorphism end
end
Exercise: Make the COMPOSITE class iterable. 14 of 18
Testing the Composite Pattern
test_composite_equipment: BOOLEAN local
card, drive: EQUIPMENT
cabinet: CABINET — holds a CHASSIS
chassis: CHASSIS — contains a BUS and a DISK_DRIVE bus: BUS — holds a CARD
do
create {CARD} card.make(“16Mbs Token Ring”, 200)
create {DISK_DRIVE} drive.make(“500 GB harddrive”, 500) create bus.make(“MCA Bus”)
create chassis.make(“PC Chassis”)
create cabinet.make(“PC Cabinet”)
bus.add(card) chassis.add(bus) chassis.add(drive) cabinet.add(chassis)
Result := cabinet.price = 700
end
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Index (1)
Motivating Problem (1)
Motivating Problem (2)
Multiple Inheritance:
Combining Abstractions (1)
MI: Combining Abstractions (2.1)
MI: Combining Abstractions (2)
MI: Name Clashes
MI: Resolving Name Clashes
Solution: The Composite Pattern
Composite Architecture: Design (1.1)
Composite Architecture: Design (1.2)
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Index (2)
Composite Architecture: Design (2.1)
Implementing the Composite Pattern (1)
Implementing the Composite Pattern (2.1)
Implementing the Composite Pattern (2.2)
Testing the Composite Pattern
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