Metamodel Search: Using XPath for Searching DomainSpecific Models

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Meta-model Search Using XPath for Searching
Domain-Specific Models
Thesis Proposal

• Rajesh Sudarsan
• Department of Computer and Information Science
• University of Alabama at Birmingham
• sudarsar_at_cis.uab.edu
• Advisor Dr. Jeff Gray

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Research Goal
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Outline

• Introduction to Searching

• Background

• Existing Search utilities
• Domain-specific Modeling and GME

• Motivation and Proposed research

• Timeline and Progress

• Summary

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Basics

• The keys to successful searching are
• Choosing the right search tool
• Knowing about search strategies and how to use
  them
  
• Information Retrieval and Data Retrieval

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Example Search Domains

• Text Processing tools
• E.g. Microsoft Word
• World Wide Web
• E.g. Google
• Software Development tools
• E.g. Microsoft Visual C, Eclipse

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Search utility in MS Word, Google
Advanced search options in Google
Find/Replace utility in MS Word
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Searching in Domain Application modeling
Environment

• Domain
• Group of entities that share the same
  characteristics or exhibit similar functionality
  
• Product Line Architecture
• Do not support advanced search capabilities

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Outline

• Introduction to Searching

• Background

• Existing Search utilities
• Domain-specific Modeling and GME

• Motivation and Proposed research

• Timeline and Progress

• Summary

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Existing Search Utilities

• JQuery
• XQuery
• XPath

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JQuery

• Developed by Software Practices Lab at the
  University of British Columbia
  
• Eclipse Plug-in
• Set of TyRuBa predicates

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JQuery in Eclipse
User can edit exiting Queries or write his own
queries
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XQuery

• W3C standard for querying XML documents
• Each query is an expression
• Data model is based on XPath and XML Schema

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Types of XQuery expressions

• Path Expressions
• document(ATM.xml)//activitytitleDeposit//a
  mount _at_value
  
• Element Constructors

name
job deptno
NETspecialist100000

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Types (contd.)

• FLWOR- For-Let-Where-Order-Return

for d in document("depts.xml")//deptno
let e document("emps.xml")//employeedeptno
d where count(e) 10 order by avg(e/salary
) descending return d,
count(e),
avg(e/salary)

• Operators and Functions
• (e.g. Sum, Avg)

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Types (contd.)

• Quantified Expressions

for b in document("bib.xml")//book
where some p in b//paragraph satisfies
(contains(p,"sailing") AND contains(p,"windsur
fing")) return b/title

• Test or modify data
• (e.g. instance-of, typeswitch/case)

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XPath

• W3C standard
• Select parts of an XML document
• Support for querying
• Mainly used in XSLT
• XPath syntax is stricter as compared to XQuery
• Everything is a expression
• Expressions are resolved with respect current
  node or root node

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XML document Tree Structure
? pin"id2345" Depositing Moneytle 12323.92 osit Withdrawing Money 34234.
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Types of XPath nodes 1) Root 2) Element 3) Tex
t 4) Attribute 5) Comment 6) Processing Instr
uction
7) Namespaces
Kind of Nodes
Element
Root
Attribute
Text
Transaction
Root
date
Deposit
Withdraw

title
comment
amount
pin
title
comment
amount
pin



.




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Expressions

• Primary Expressions
• Literals, Operators, Functions (Node-set, String,
  Boolean, and Number)
  
• Arithmetic expressions
• Location Paths
• Axis
• Node tests
• Predicates
• Complex Expressions

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Location Path

• Axes
• Relationship between the context node and
• the nodes selected by the location step
• self, child, descendent-or-self, parent,
• attribute, descendent, ancestor, ancestor-or-
• self, preceding, preceding-sibling, following,
  
  
• following-sibling, and namespace

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Location Path (contd.)

• Node tests
• Specifies the types of the nodes that will be
• selected
• Name, , comment (), text (), node (),
• processing-instruction (), and processing-
• instruction (value)
• Predicates
• Specific conditions enclosed in

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Additional Operators
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Example
XPath Expressions
XML Document

• The Wall
• Pink Floyd
• 10.90
• Patience
• George Michael
• 9.90
• The Very Best Of Rod Stewart
  
  
• Rod Stewart
• 9.90

1. To display the price of all CDs. Expres
sion /catalog/cd/price 2. List the title, arti
st and price of all CDs. Expression /catalog
/cd/ 3. List all information about everything
in the catalogue Expression // 4.
Select the CD whose price is 10.90
Expression /catalog/cdprice10.90
5. List those CDs that have some informatio
n associated with it Expression //cd_at_
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Domain-specific Modeling and GME

• What are Models?
• Models are an abstract representation of real
  world systems or process.
  
• Domain-Specific Models (DSM)
• Models that address a particular domain

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Model Integrated Computing (MIC)

• Definition
• Model Integrated Computing (MIC) is a
  model-based approach to software development,
  facilitating the synthesis of application
  programs from models created using customized,
  domain-specific program synthesis environments

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MIC Architecture
1
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Environment
Application
2
A3
A1
A2
4
5
3
8
6
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1. Meta-programming
2. Formal Specification
5. Model Builder
8. Model Interpretation
3. Meta-level Translation
6. Models
9. Application Domain
4. MIPS Environment
7. Model Interpreter
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Modeling Concepts

• Metamodel
• A metamodel for a domain is defined as the
  modeling paradigm captured in the form of a
  formal modeling language.
  
• Modeling Paradigm
• The modeling paradigm is a set of requirements
  that specifies the ontology of the domain.

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Meta Object Facility (MOF)
Metamodeling Language
Language for defining Metamodels
Meta-metamodel
Specify
Metamodeling Language
An instance of meta-metamodel. Defines the
language for specifying a model
Metamodel
Specify
Domain modeling Language
An instance of metamodel. Defines the language
for describing the information domain

Model
Specify
Computer Based System
An instance of a model. Defines a specific
information domain

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Metamodel and Constraints
Constraint based Metamodel for FSM
Finite State Machine Metamodel
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Generic Modeling Environment (GME)
Metamodel

• Meta-programmable toolkit based on the
  principles of MIC
  
• Configurable toolkit for creating DSM and
  program synthesis environments
  
• Meta-models specify the modeling paradigm

Domain-specific Model
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GME Modeling Concept

• Supports hierarchy, multiple aspects, sets,
• references, and explicit constraints

Root (Model)
Atoms
References
Sets
Models
Connections
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GME Builder Object Network (BON)

• C framework to access and instantiate objects
  in GME model database

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Outline

• Introduction to Searching

• Background

• Existing Search utilities
• Domain-specific Modeling and GME

• Motivation and Proposed research

• Timeline and Progress

• Summary

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Motivation

• The capability to efficiently search an artifact
  that is being created is absent in GME
  
• Serious disadvantage as the size of a model
  increases to hundreds of modeling elements.
  (1000 modeling elements)
  
• Example Automobile manufacturing industry,
  Aviation design center

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Existing Feature
Current implementation of Find utility in GME

• The searching is limited to the options provided
• Any search involving inequality sign ()
  cannot be expressed in the current tool

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Proposed Research

• Develop a search plug-in in C using XPath for
  writing search predicates
  
• Current implementation will be part of GME.
• Use GME Builder Object Network (BON) to search
  model database instead of XML file.

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XPath MOdel Search Plug-in Architecture
XPath Evaluator
Parse tree
Translator (Customized Data Structure)
XPath Expression
XPath Parser
Search Algorithm
GME Builder Object Network
Model list
C API
Output
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GME hierarchy in XPath

• XPath uses the tree hierarchy in GME to express
  search queries
  
• The XPath search engine traverses the internal
  GME representation for the domain model and
  returns those model entities that match the
  search predicate
• The expression attribute will be matched with the
  kind value of the artifact being searched

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XMOS Plug-in Screenshot
User enters XPath expression
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Supported XPath features in XMOS
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Outline

• Introduction to Searching

• Background

• Existing Search utilities
• Domain-specific Modeling and GME

• Motivation and Proposed research

• Timeline and Progress

• Summary

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Timeline

• Main Tasks
• Development of the XPath engine
• Search Algorithm and User Interface
• Testing

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Progress Chart
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Outline

• Introduction to Searching

• Background

• Existing Search utilities
• Domain-specific Modeling and GME

• Motivation and Proposed research

• Timeline and Progress

• Summary

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Summary

• Searching entities through Domain Models in large
  systems made simpler and efficient.
  
• Properties of similar entities can be modified
  easily in CBS
  
• Every model returned by search algorithm will be
  a link to exact location of the model
  
• Future Scope
• Generic search plug-in adaptable with all
• modeling environments

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Questions?
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