Pipes and Filters

This post is a definition of terms for the architectural pattern Pipes and Filters – including exam questions and tags.

In a Nutshell

Data flows through a chain of processing steps (Filters), connected via standardized interfaces (Pipes).

Compact Technical Description

Each filter is an independent processing unit: Input → Transformation → Output. Pipes transport data between filters. The pattern is suitable for conversion, validation, compilation, audio/video pipelines, or ETL.

Exam-Relevant Key Points

• Filters are independent processing units
• Pipes connect filters linearly/branched
• Good for streaming or batch processing
• Practice: Compiler phases, log processing
• Security: Validation/sanitization filters
• Cost-effectiveness: Reusable filters
• Document modularly (IHK-relevant)

Core Components

1. Source (file/stream/API)
2. Filter (validation)
3. Filter (transformation)
4. Filter (aggregation)
5. Pipes between filters
6. Data format between filters
7. Error handling per filter
8. Logging
9. Parallelization
10. Target (DB/file)

Practical Example (Log Processing)

Pipe-In: reads log file
Filter 1: removes blank lines
Filter 2: extracts errors
Filter 3: counts errors per type
Pipe-Out: writes result to CSV

Advantages and Disadvantages

Advantages

• Modular and reusable
• Well testable
• Easy to extend
• Parallel processing possible

Disadvantages

• Overhead for small data volumes
• Error handling across many filters is complex
• Uniform data format required

Typical Exam Questions (with Brief Answer)

1. What is Pipes and Filters? Chained filters process data sequentially.
2. What is it suitable for? Data streams, ETL, compilers, streaming.
3. Why is it test-friendly? Each filter is testable in isolation.

Open-Ended Answer

For project documentation, the pattern is ideal when you build import/transformation/analysis as a pipeline. It can be well represented with data flow diagrams.

Learning Strategy

1. Build a mini-chain CSV → Filter → JSON.
2. Implement a small ETL pipeline.
3. Document the filter process as a diagram.
4. Define interface formats clearly.

Further Information

1. https://camel.apache.org/
2. https://spring.io/projects/spring-integration