Local search-based pattern matching features in EMF-IncQuery

Local Search-basedPattern Matching Features in

EMF-IncQuery

2015. 07. 22. 1Local search-based pattern matching features in EMF-IncQuery

Márton Búr, Zoltán Ujhelyi, Ákos Horváth, Dániel Varró

Presenter: Ábel Hegedüs

IncQuery Labs Ltd.

Budapest University of Technology and Economics

Anti-pattern Detection in Java Programs


public class StringLiteralCompareTest {

public StringLiteralCompareTest srcVar;

@Overridepublic boolean equals(Object other) {

return super.equals(other);}

public void test() {

srcVar.equals("source");}

}









}

EMF metamodel of Java programs (part)









}

Instance model in EMF editor









}

String Literal as Compare Parameter(anti-pattern as graph pattern)

inv: MethodInvocation

name = “equals”

m: NormalMethod

arg: StringLiteral

op: Literal

invokes operand

argument

check count matches == 1

: Expression

Pattern Matching Strategies


Local Search• Executes a search plan• Lower memory requirements• Tools: ATL, GrGen.net, FUJABA, …

Incremental• Maintains a cache structure• Efficient recalculation• Tools: EMF-IncQuery, Drools, ...

Local-search Based Pattern Matching


Find all m that m ∈ NormalMethod

Attribute test: m.name=="equals”

Find inv that inv.invokes → m

Count of inv.argument → arg is 1

Find arg that inv.argument → arg

Instance test: arg is a StringLiteral

Find op that inv.operand → op

NEG: op is not a Literal87

6

5

4

3

21



Normal Method1









6

5

4

3

21



Normal Method1

2









6

5

4

3

21

name: “equals”



Normal Method

MethodInvocation

invokes

1

2

3









6

5

4

3

21

name: “equals”



Normal Method

StringLiteral

MethodInvocation

invokes

1

2

36









6

5

4

3

21

name: “equals”



Normal Method

StringLiteral

IdentifierMethod

Invocation

invokes

1

2

36

8









6

5

4

3

21

name: “equals”

EMF-IncQuery


Runtime

Incremental queries using Rete backend

Local search backend

IDE

Language

Code generator

Development tools

Query Explorer

Local Search Debugger

Local Search Runtime


IncQuery Engine

Model

Graph patterns



IncQuery Engine

Model

Graph patterns

• Calculates matches• Manages model indexes



IncQuery Engine

Model Rete backend

Graph patterns



IncQuery Engine

Model Rete backend

Graph patterns

Default (incremental) query executor



IncQuery Engine

Model Rete backend

Graph patterns

Pattern matches



IncQuery Engine

Model


Planner

Graph patterns

Pattern matches

• Initializes search plans• Reuses pre-populated

model indexes



IncQuery Engine

Model


Planner Matcher

Graph patterns

Pattern matches• Executes search plans• Based on depth-first search

EMF-IncQuery IDE


EMF-IncQuery IDE


Query Editor

Defines graph patterns

Model Editor

EMF-based editor

Query Explorer

Displays query results



Step-by-step execution of search plans• Visualizes search plans• Visualizes (partial) query results



Step-by-step execution of search plans• Visualizes search plans• Visualizes (partial) query results


• Based on local search• Visualizes query

structure• Step-by-step

execution

Query Explorer

• Relies on incremental query evaluation

• Reacts on model changes

• Results can be filtered

DEMO


Performance Characteristics – 1.


1

10

100

1000 10000 100000

SEAR

CH T

IME

(S)

PROGRAM SIZE (LOC)

LS INC LS (100) INC (100) LS INC LS (100) INC (100)

Incremental approach is beneficial in case of re-evaluation

Performance Characteristics – 2.


1

10

100

1000

10000

100000

1000 10000 100000 1000000 10000000

MEM

ORY

USA

GE

(MB)

PROGRAM SIZE (LOC)

LS INC LS INC

Local search works uses less memory

Summary

Local search based pattern matcher• Alternative execution strategy• Reuses existing infrastructure

Search Plan Debugger• Step-by-step execution of search plans• Complements Query Explorer

Future plans• Enhanced search plan generation• Hybrid pattern matching


Local search-based pattern matching features in EMF-IncQuery

Science

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