XSnippet: Mining For Sample Code

1
XSnippet Mining For Sample Code

• Naiyana Tansalarak and Kajal Claypool
• Presented by Shan Li
• CISC864

2
Topics

• Overall of Research
• Purposes
• Contributions
• Approaches
• Detail in Approaches

3
Overall of Research

• Purposes
• To provide sample codes for new developers to
  learn tech. quickly
• Approaches
• Mining sample codes from existing software
  systems

4
Overall of Research cont.

• Steps in Approaches
• Range of Queries generalized / specialized?
• Ranking Heuristics for context-sensitive /
  context-independence
• Such as constructor function / constructor
  function of DOM
• Mining Algorithms
• BFSMINE Alg. , restricts inside a scope of a
  method
• Extensions to BFSMINE Alg.

5
Approaches the Snippet Mining Processes
Figure1 A high-level view of the snippet Mining
Process
6
Approaches cont.

• The goal of the snippet mining is to mine from a
  given code sample repository all code snippets
  that satisfy a given user query Q,
• SelectionAgent pre-selects a set of code model
  instances cmi on B tree index defined on all
  types declared or referred to in the code sample
  repository.
• The MiningAgent invokes the BFSMINE algorithm for
  every code model instance

7
Approaches cont.

• BFSMINE algorithm
• traverses a code model instance and produces
  as output a set of paths P that represent the
  final code snippets returned to the user.
• On completion of the BFSMINE phase, the
  MiningAgent passes the collection of the paths P,
  to the PruningAgent.

8
Approaches cont.

• Queries
• The query retun all snippets s, containing codes
  that instantiate a type tq
• (1) all codes that instantiate tq
• (2) instantiation of tq is dependent of the code
  context, i.e. via a static method
• The following example

9
Approaches cont.
10
Approaches cont.

• Queries
• A type-based instantiation query
• tq is instantiated from any type from the
  context CT(m)
• T (s) the lexically visible types in the code
  snippet s and CT (m) denotes the type context of
  the method
• CT (m) all set of inherited types, visible
  types in a scope of method, all types for local
  fields

11
Approaches cont.
12
Approaches cont.

• Queries
• Parent-based in instantiation query
• s denotes a snippet, CP (s) the parent context of
  the snippet, CP (m) the parent context of the
  method m.
• CP (m) The parent context of a method m, denoted
  as CP (m), is a set containing the superclass
  extended by its containing source class C, as
  well as all interfaces implemented by its
  containing source class C.

13
Approaches cont.
14
Approaches cont.

• Source Code Model
• A graphic representation of the structure of
  source codes. Nodes a type node, an object node,
  a method node
• Edges inheritance, implement, composite, method,
  assignment or parameter edge.

15
Approaches cont.

• BFSMINE Algorithm
• Given a user query , The goal of the BFSMINE
  algorithm is to determine for all such instances
  nq, types and eventually code segments that
  instantiate the node nq and hence the query type
  tq. Domain(nq) tq

16
Approaches cont.
17
Approaches cont.
Extension-BFSMIN
18
Approaches cont.
Extension-BFSMIN
19
Approaches cont.
20
Personal Comments

• Strengths
• User defined queries
• Results from a context-independent retrieval to
  various degrees of context-sensitive retrieval
• BFSMIN Algorithm based on a graph that represents
  a source code model allows mining across method
  boundaries
• Ranking heuristic (length, frequency, context )
  for providing best-fit code snippets
• Multiple sample codes with the same query
• context-independent retrieval (length / frequency
  )
• context-sensitive retrieval (context)

21
Personal Comments

• Potential weakness
• Results
• Is it possible to provide semantic ranking ?
• Why? Probably, the return code snippets do not
  have logic among them, just only a chunk of codes
• Validation approaches
• To prove that snippet codes is helpful for
  developers, authors use group test. Two groups
  with the same condition except that one uses
  snippet codes, other do not.
• Limited ?