1. Cross-library API Recommendation Using Web Search Engines
Wujie Zheng, Qirun Zhang, Michael R. Lyu
Department of Computer Science & Engineering
The Chinese University of Hong Kong
Sep. 8, 2011
Dept. of Computer Science & Engineering, CUHK
ESEC/FSE 2011, Szeged, Hungary, Sep. 5-9, 2011

2. Cross-references of APIs
Research Problem
How to find cross-references of APIs in different libraries?
Programming Tasks
Library S: some APIs
Cross-references of APIs
Library T: what APIs

3. Related Work Recommending APIs in the same library
Analyzing library code
Call graph: Robillard05 (Suade), Saul07 (FRAN)
Access graph: Robillard05 (Suade), Long09 (Altair)
Our work
Analyze the control-flow graph to capture the significance of the caller-callee linkages

4. Related Work Recommending APIs in the same library
Analyzing client code
Frequent itemset mining: Li05 (PR-Miner)
Code search engines: Thummalapenta07 (PARSEWeb)
Recommending APIs in different libraries
Analyzing client code
API mapping: Zhong10 (MAM)

5. The world of users’ knowledge
Our New Idea
From code to users’ knowledge
Developers ask for and share knowledge of APIs in the Web
The world of users’ knowledge
Code repository

6. Motivating Example
Developers ask equivalent APIs in C# for the “HashMap” class in Java

7. The Approach
Overview
Input: API lists of the source (S) and target (T) libraries
Output: Relevant APIs in T for each API in S

8. The Approach Web query construction Querying Web search engines
The source API + the target library’s name
Querying Web search engines
Web services of Google’s Web search

9. The Approach Mining API candidates Dictionary-based approach
Require the API list of the target library as inputs
Calculate the frequency of each target API in the Web search results

10. The Approach Ranking w.r.t. the whole library
To reduce the noise (common target APIs)
For a source API Q and a target API T
tf(T,Q): the frequency of T in Q’s search results
idf(T): dividing the total number of source APIs by the number of source APIs whose search results containing T, and then taking the logarithm

11. Preliminary Results
From JDK to .NET

12. Discussions Web-query construction API candidates extraction
Extract keywords from a source API’s doc
API candidates extraction
Analyze the source code
Using templates (regular expressions)
API usage pattern mapping
From recommending single APIs to recommending API lists (sequences)

13. Q&A
Thanks!