130614   sebastiano panichella -  mining source code descriptions from developers communications
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130614 sebastiano panichella - mining source code descriptions from developers communications

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Software mining, source code, developers, e-mails

Software mining, source code, developers, e-mails

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130614   sebastiano panichella -  mining source code descriptions from developers communications 130614 sebastiano panichella - mining source code descriptions from developers communications Presentation Transcript

  • Mining Source Code Descriptions from Developer Communications Sebastiano Panichella Jairo Aponte Massimiliano Di Penta Andrian Marcus Gerardo Canfora
  • Context: Software Project Sequence diagram Documentation Source Code Class diagram Developer Program Comprehension Maintenance Tasks
  • Context: Software Project Sequence diagram Documentation Source Code Class diagram Difficult understanding Developer Program Comprehension Maintenance Tasks
  • Context: Software Project describes Sequence diagram Documentation Source Code Class diagram Difficult understanding understanding Developer Program Comprehension Maintenance Tasks
  • Context: Software Project Coming back to the reality... Program Comprehension Source Code Maintenance Tasks Difficult understanding Developer
  • Idea We argue that messages exchanged among contributors/developers are a useful source of information to help understanding source code. In such situations developers need to infer knowledge from, the source code itself Developer source code descriptions in external artifacts.
  • .................................................. When call the method IndexSplitter.split(File destDir, String[] segs) from the Lucene cotrib directory(contrib/misc/src/java/org/apache/luc ene/index) it creates an index with segments descriptor file with among contributors/developers We argue that messages exchanged wrong data. Namely wrong are a useful source of information to help understanding of segment is the number representing the name source code. that would be created next in this index. Idea .................................................. In such situations developers need to infer knowledge from, CLASS: IndexSplitter the source code itself Developer METHOD: split source code descriptions in external artifacts.
  • A Five Step-Approach for Mining Method Descriptions Developer
  • Step 1: Downloading emails/bugs reports and tracing them onto classes Two heuristics Developer Discussion The discussion contains a fully-qualified class name (e.g., org.apache.lucene.analysis.MappingCharFilter); or the email contains a file name (e.g., MappingCharFilter.java) For bug reports, we complement the above heuristic by matching the bug ID of each closed bug to the commit notes, therefore tracing the bug report to the files changed in that commit When call the method IndexSplitter .split(File destDir, String[] segs) from the Lucene cotrib directory (contrib/misc/src/java/org/apache/lucene/index) it creates an index with segments descriptor file with wrong data. Namely wrong is the number representing the name of segment that would be created next in this index. public void split(File destDir, String[] segs) throws IOException { destDir.mkdirs(); FSDirectory destFSDir = FSDirectory.open(destDir); SegmentInfos destInfos = new SegmentInfos } If some of the segments of the index already has this name this results either to impossibility to create new segment or in crating of an corrupted segment.
  • Step 1: Downloading emails/bugs reports and tracing them onto classes Two heuristics Developer Discussion The discussion contains a fully-qualified class name (e.g., org.apache.lucene.analysis.MappingCharFilter); or the email contains a file name (e.g., MappingCharFilter.java) For bug reports, we complement the above heuristic by matching the bug ID of each closed bug to the commit notes, therefore tracing the bug report to the files changed in that commit When call the method IndexSplitter .split(File destDir, String[] segs) from the Lucene cotrib directory (contrib/misc/src/java/org/apache/lucene/index) it creates an index with segments descriptor file with wrong data. Namely wrong is the number representing the name of segment that would be created next in this index. CLASS: IndexSplitter public void split(File destDir, String[] segs) throws IOException { destDir.mkdirs(); FSDirectory destFSDir = FSDirectory.open(destDir); SegmentInfos destInfos = new SegmentInfos } If some of the segments of the index already has this name this results either to impossibility to create new segment or in crating of an corrupted segment.
  • Step 2: Extracting paragraphs We consider as paragraphs, text section separated by one or more white lines Two heuristics We prune out paragraph description from source code fragments and/or stack Traces "by using an approach inspired by the work of Bacchelli et al. Developer Discussion When call the method IndexSplitter.split(File destDir, String[] segs) from the PAR Lucene cotrib directory (contrib/misc/src/java/org/apache/lucene/index) it creates 1 an index with segments descriptor file with wrong data. Namely wrong is the number representing the name of segment that would be created next in this index. public void split(File destDir, String[] segs) throws IOException { destDir.mkdirs(); FSDirectory destFSDir = FSDirectory.open(destDir); SegmentInfos destInfos = new SegmentInfos } PAR 2 If some of the segments of the index already has this name this results either to impossibility to create new segment or in crating of an corrupted segment. PAR 3
  • Step 2: Extracting paragraphs We consider as paragraphs, text section separated by one or more white lines Two heuristics We prune out paragraph description from source code fragments and/or stack Traces "by using an approach inspired by the work of Bacchelli et al. Developer Discussion When call the method IndexSplitter.split(File destDir, String[] segs) from the PAR Lucene cotrib directory (contrib/misc/src/java/org/apache/lucene/index) it creates 1 an index with segments descriptor file with wrong data. Namely wrong is the number representing the name of segment that would be created next in this index. public void split(File destDir, String[] segs) throws IOException { destDir.mkdirs(); FSDirectory destFSDir = FSDirectory.open(destDir); SegmentInfos destInfos = new SegmentInfos } PAR 2 If some of the segments of the index already has this name this results either to impossibility to create new segment or in crating of an corrupted segment. PAR 3
  • Step 3: Tracing paragraphs onto methods A) A valid paragraph must contain the keyword “method” These paragraphs must respect the following two conditions: Developer Discussion A) B) and the method name must be followed by a open parenthesis— i.e., we match “foo(” B) When call the method IndexSplitter.split(File destDir, String[] segs) PAR from the Lucene cotrib directory it creates an index with segments1 descriptor file with wrong data. Namely wrong is the number representing the name of segment that would be created next in this index. CLASS: IndexSplitter METHOD: split( ...................................................................................... ...................................................................................... ...................................................................................... ......................................................................................
  • Step 4: Heuristic based Filtering We defined a set of heuristics to further filter the paragraphs associated with methods that assign each paragraph a score: .......................... Problem seems to come from MainMethodeSearchEngine in org.eclipse.jdt.internal.ui.launcher The Method searchMainMethods(IProgressMonitor, IJavaSearchScope, boolean) ,there's a call to addSubTypes(List, IProgressMonitor, IJavaSearchScope) Method if includesSubtypes flag is ON. This method add all types subtypes as soon as the given scope encloses them without testing if sub-types have a main! After return IType[] before the excecution .......................... CLASS: MainMethodSearchEngine METHOD: serachMainMethods SCORE
  • Step 4: Heuristic based Filtering We defined a set of heuristics to further filter the paragraphs associated with methods that assign each paragraph a score: .......................... Problem seems to come from MainMethodeSearchEngine in org.eclipse.jdt.internal.ui.launcher The Method searchMainMethods(IProgressMonitor, IJavaSearchScope, boolean) ,there's a call to addSubTypes(List, IProgressMonitor, IJavaSearchScope) Method if includesSubtypes flag is ON. This method add all types subtypes as soon as the given scope encloses them without testing if sub-types have a main! After return IType[] before the excecution .......................... CLASS: MainMethodSearchEngine METHOD: serachMainMethods % parameter = 100% -> s1= 1 SCORE a) Method parameters: % of parameters s1= mentioned in the paragraphs. Value between 0 and 1 1 if the method does not have parameters
  • Step 4: Heuristic based Filtering We defined a set of heuristics to further filter the paragraphs associated with methods that assign each paragraph a score: .......................... Problem seems to come from MainMethodeSearchEngine in org.eclipse.jdt.internal.ui.launcher The Method searchMainMethods(IProgressMonitor, IJavaSearchScope, boolean) ,there's a call to addSubTypes(List, IProgressMonitor, IJavaSearchScope) Method if includesSubtypes flag is ON. This method add all types subtypes as soon as the given scope encloses them without testing if sub-types have a main! After return IType[] before the excecution .......................... CLASS: MainMethodSearchEngine METHOD: serachMainMethods % parameter = 100% -> s1= 1 SCORE = 1+ a) Method parameters: % of parameters s1= mentioned in the paragraphs. Value between 0 and 1 1 if the method does not have parameters b) Syntactic descriptions (mentioning return values): check whether the Equal to one if paragraph contains the the method is s2= keyword “return”. If YES void. Value equal 1, 0 otherwise
  • Step 4: Heuristic based Filtering We defined a set of heuristics to further filter the paragraphs associated with methods that assign each paragraph a score: .......................... Problem seems to come from MainMethodeSearchEngine in org.eclipse.jdt.internal.ui.launcher The Method searchMainMethods(IProgressMonitor, IJavaSearchScope, boolean) ,there's a call to addSubTypes(List, IProgressMonitor, IJavaSearchScope) Method if includesSubtypes flag is ON. This method add all types subtypes as soon as the given scope encloses them without testing if sub-types have a main! After return IType[] before the excecution .......................... CLASS: MainMethodSearchEngine METHOD: serachMainMethods % parameter = 100% -> s1= 1 SCORE = 1+ 0+ 1 = 2 a) Method parameters: % of parameters s1= mentioned in the paragraphs. Value between 0 and 1 1 if the method does not have parameters b) Syntactic descriptions (mentioning return values): check whether the Equal to one if paragraph contains the the method is s2= keyword “return”. If YES void. Value equal 1, 0 otherwise c) Overriding/Overloading: 1 if any of the “overload” or s3=“override” keywords appears in the paragraph, 0 otherwise d) Method invocations: 1 if any of the “call” or s4=“excecute” keywords appears in the paragraph, 0 otherwise
  • Step 4: Heuristic based Filtering We defined a set of heuristics to further filter the paragraphs associated with methods that assign each paragraph a score: We selected paragraphs that have: 1. s1 ≥ thP = 0.5 2. s2 + s3 + s4 ≥ thH = 1 a) Method parameters: % of parameters s1= mentioned in the paragraphs. Value between 0 and 1 b) Syntactic descriptions (mentioning return values): check whether the Equal to one if paragraph contains the the method is s2= keyword “return”. If YES void. Value equal 1, 0 otherwise OK % parameter = 100% -> s1= 1 ≥ 0.5 SCORE = 1+ 0+ 1 = 2 ≥ 1 1 if the method does not have parameters c) Overriding/Overloading: 1 if any of the “overload” or s3=“override” keywords appears in the paragraph, 0 otherwise d) Method invocations: 1 if any of the “call” or s4=“execute” keywords appears in the paragraph, 0 otherwise
  • Step 5: Similarity based Filtering We rank filtered paragraphs through their textual similarity with the method they are likely describing. METHOD PARAGRAPH SCORE Similarity Method_3 Paragraph_4 2.5 96.1% Method_1 Paragraph_1 2.5 95.6% Method_2 Paragraph_2 1.5 97.4% Method_3 Paragraph_3 1.5 86.2% Method_1 Paragraph_3 1.5 79.0% Method_3 Paragraph_2 1.5 77.5% Method_2 Paragraph_4 1.5 64.3% Method_2 Paragraph_3 1.3 83.2% Method_3 Paragraph_1 1.3 73.9% Method_2 Paragraph_1 1.3 68.7% Method_1 Paragraph_4 1.3 53.6% Removing: - English stop words; - Programming language keywords Using: - Camel Case splitting the on remaining words - Vector Space Model
  • Step 5: Similarity based Filtering We rank filtered paragraphs through their textual similarity with the method they are likely describing. METHOD PARAGRAPH SCORE Similarity Method_3 Paragraph_4 2.5 96.1% Method_1 Paragraph_1 2.5 95.6% Method_2 Paragraph_2 1.5 97.4% Method_3 Paragraph_3 1.5 86.2% Method_1 Paragraph_3 1.5 79.0% Method_3 Paragraph_2 1.5 77.5% Method_2 Paragraph_4 1.5 64.3% Method_2 Paragraph_3 1.3 83.2% Method_3 Paragraph_1 1.3 73.9% Method_2 Paragraph_1 1.3 68.7% Method_1 Paragraph_4 1.3 53.6% Removing: - English stop words; - Programming language keywords Using: - Camel Case splitting the on remaining words - Vector Space Model th>=0.80
  • Empirical Study • Goal: analyze source code descriptions in developer discussions • Purpose: investigating how developer discussions describe methods of Java Source Code • Quality focus: find good method description in messages exchanged among contributors/developers • Context: Bug-report and mailing lists of two Java Project  Apache Lucene and Eclipse
  • Context
  • Research Questions  RQ1 (method coverage): How many methods from the analyzed software systems are described by the paragraphs identified by the proposed approach?  RQ2 (precision): How precise is the proposed approach in identifying method descriptions?  RQ3 (missing descriptions): How many potentially good method descriptions are missed by the approach?
  • RQ1: How many methods from the analyzed software systems are described by the paragraphs identified by the proposed approach?
  • RQ1: How many methods from the analyzed software systems are described by the paragraphs identified by the proposed approach?
  • RQ1: How many methods from the analyzed software systems are described by the paragraphs identified by the proposed approach?
  • RQ2: How precise is the proposed approach in identifying method descriptions? We sampled 250 descriptions from each project
  • RQ2: How precise is the proposed approach in identifying method descriptions? We sampled 250 descriptions from each project
  • RQ2: How precise is the proposed approach in identifying method descriptions? We sampled 250 descriptions from each project
  • RQ3: How many potentially good method descriptions are missed by the approach? We sampled 100 descriptions from each project TABLE III The analysis of a sample of 100 paragraphs traced to methods, but not satisfying the Step 4 heuristic System True Negatives False Negatives Eclipse 78 22 Apache Lucene 67 33
  • Conclusion
  • Conclusion
  • Conclusion
  • Conclusion