Pattern selection guidelines in Software Engineering - Step-by-Step Execution

Concept Flow - Pattern selection guidelines

Identify Problem

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Analyze Context

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List Candidate Patterns

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Evaluate Patterns

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Select Best Fit Pattern

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Apply Pattern

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Review and Adjust

The flow shows how to select a design pattern by understanding the problem, analyzing context, listing options, evaluating them, choosing the best, applying it, and then reviewing.

Execution Sample

Software Engineering

Problem: Need to manage object creation
Context: Complex object with many parts
Candidate Patterns: Builder, Factory
Evaluate: Builder fits complex stepwise creation
Select: Builder
Apply: Implement Builder pattern

This example traces selecting the Builder pattern for complex object creation.

Analysis Table

Step	Action	Details	Decision/Result
1	Identify Problem	Need to create complex objects stepwise	Proceed to analyze context
2	Analyze Context	Objects have many parts and steps	List candidate patterns
3	List Candidate Patterns	Builder, Factory, Prototype	Evaluate suitability
4	Evaluate Patterns	Builder fits stepwise creation best	Select Builder
5	Select Best Fit Pattern	Builder pattern chosen	Apply pattern
6	Apply Pattern	Implement Builder classes and steps	Review implementation
7	Review and Adjust	Check if pattern solves problem effectively	Adjust if needed

💡 Pattern selected and applied after evaluation and review

State Tracker

Variable	Start	After Step 2	After Step 4	Final
Problem	Unknown	Complex object creation	Complex object creation	Complex object creation
Context	Unknown	Objects with many parts	Objects with many parts	Objects with many parts
Candidate Patterns	None	Builder, Factory, Prototype	Builder, Factory, Prototype	Builder
Selected Pattern	None	None	Builder	Builder

Key Insights - 3 Insights

Why do we analyze context before listing patterns?

Analyzing context helps understand constraints and requirements, which guides listing relevant patterns. See execution_table step 2 and 3.

Can we select a pattern without evaluating candidates?

No, evaluation ensures the chosen pattern fits the problem well. Skipping this risks poor design. Refer to execution_table step 4.

What if the applied pattern doesn't solve the problem?

Review and adjust step allows revisiting selection or tweaking implementation. See execution_table step 7.

Visual Quiz - 3 Questions

According to the execution_table, what is the action at step 3?

A Apply Pattern

B Analyze Context

C List Candidate Patterns

D Review and Adjust

💡 Hint

Look at the 'Action' column in execution_table row with Step 3

At which step is the pattern finally selected?

A Step 2

B Step 4

C Step 6

D Step 7

💡 Hint

Check the 'Decision/Result' column for when selection happens in execution_table

If the problem was simple object creation, how would the candidate patterns list change?

A Include Factory and Singleton

B Include only Builder

C Include Builder and Factory

D No patterns needed

💡 Hint

Consider common patterns for simple object creation, referencing candidate patterns in variable_tracker

Concept Snapshot

Pattern Selection Guidelines:
1. Identify the problem clearly.
2. Analyze the context and constraints.
3. List possible design patterns.
4. Evaluate each pattern's fit.
5. Select and apply the best pattern.
6. Review and adjust as needed.

Full Transcript

Pattern selection involves a step-by-step process starting with identifying the problem, then analyzing the context to understand constraints. Next, list candidate design patterns that might solve the problem. Evaluate these patterns to see which fits best. Select the best fit pattern and apply it in your design. Finally, review the implementation and adjust if necessary to ensure the problem is solved effectively.