sharing this in android taipei 201709 meetup.

1. Big-JSON Problem
Prada
JSON
Prada - PicCollage Android Dev

2. How Big JSON You
Had Parsed?
10Bytes?
1KB?
1MB?
1GB?

3. Collage Struct

4. Doodle Feature

5. Doodle Struct
Path
Point : {x, y}
2 strokes, each has 3 paths
Stroke1
Stroke2

6. Doodle Example
https://pic-collage.com/_szHXacnx/

7. How to parse a JSON(1/2)
• Traditional Way
• org.json.JSON
• com.google.gson.GSON
• Moshi(Doc)
Time : O(2N)
Space : O(N)
Code complexity O(N)

8. How to parse a JSON(2/2)
• Streaming way(SAX)
1. com.google.gson.stream.JSONReader
2. JsonReader(API 11+)(Doc)

9. Time : O(N)
Space : O(1)
Code complexity O(!N)

10. Performance Evaluation
Test data : 100 strokes, and each stroke
includes 100 paths, and run 100 times
Library build in JSON GSON GSON.stream
Time
(seconds)
8.174 6.116 4.204

11. Conclusion
• If you do care about the performance -> SAX
• if you do care about the readability -> Traditional way
• Further Discussion
• The sketch path is useless in the collage editor
• Don’t use JSON.

12. • THX