EMF Search---Developer Guide

Introduction

Developers have several levels/contexts/persistence configurations for which they want to use EMF Search.

One aspect is which modeling level they want their extension to address :

• meta modeling level
  • Ecore meta-modeling (M3)
  • UML2 meta-modeling or custom meta-models (M2)
  • Model instance (M1)

Another aspect is where and how their meta models are stored :

• meta model persistence layer type
  • Eclipse Resources
  • Local File System
  • WWW distant resources (Close to be supported)
  • DB persistence (Support planned)

Depending on these particular situations, EMF Search typical usages exist.

Search Scope & Visitors

Search Scope

EMF Search defines a Scope API contract with IModelSearchScope :

    public interface IModelSearchScope<P, O> {
        List<P> getParticipants();
        void addParticipant(P resource);
        void addParticipants(P[] resources);
        void removeParticipant(P resource);
        void removeParticipants(P[] resources);
        List<P> findPartcipant(Class<O> clazz);
        String getLabel();
    }

These IModelSearchScope are populated with specialized visitors depending on the locations considered model resources are stored.

For the moment, main storages area are:

• Eclipse Workspace
  • IWorkspaceRoot
  • IProject[]
  • IResource (IFile, IProject, ...)
  • WorkingSet[]

• File System
  • File[]
  • Dir[]

• WWW
  • URL[]

• J2EE
  • TBD

• DataBase storage
  • TBD

Search Visitors

Model Search Visitors are usually driven thanks factories

Usual naming convention for Scope factories :

<Prefix>ModelSearch<LocationType>ScopeFactory, <Prefix>ModelSearchScope<LocationType>Visitor

• File Sytems
  • Ecore
    • EcoreModelSearchDirectoryScopeFactory
    • EcoreModelSearchFileSystemVisitor
  • UML2
    • UML2ModelSearchDirectoryScopeFactory
    • UML2ModelSearchFileSystemVisitor
• Custom
  • • <Prefix>ModelSearchDirectoryScopeFactory
    • <Prefix>ModelSearchFileSystemVisitor

• HTTP
  • Ecore
    • EcoreModelSearchHttpScopeFactory
    • EcoreModelSearchScopeHttpVisitor
  • UML2
    • UML2ModelSearchHttpScopeFactory
    • UML2ModelSearchScopeHttpVisitor
  • Custom
    • <Prefix>ModelSearchHttpScopeFactory
    • <Prefix>ModelSearchScopeHttpVisitor

• Workspace (Special case : factory take engine as parameter)
  • Ecore, UML2, Custom, ...
    • ModelSearchWorkspaceScopeFactory
    • ModelSearchScopeResourceVisitor

Ecore Query & Helper

Ecore EMF Search comes with several helpers for query building & launching :

//
// Non Case Sensitive Joker expression matching all text beginning with either 'a' or 'A'
//
private static final String ELEMENT_NAME_VALUATION_BEGINS_WITH_A = "A*";
 
//
// In this case IModelSearchScope associated to
// "org.eclipse.emf.search.ecoreSearchEngine" search engine
// will collect any files with *.ecore extension from the current
// workspace.
//
IModelSearchScope scope = 
    ModelSearchWorkspaceScopeFactory.getInstance().
        createModelSearchWorkspaceScope(
            "org.eclipse.emf.search.ecoreSearchEngine"
        );
 
//
// Creates a new query to apply on the whole workspace.
// This query will open any *.ecore collected in the
// IModelSearchScope built upper in the code
//
IModelSearchQuery query = 
    EcoreTextualModelSearchQueryBuilderHelper.getInstance().
        buildGlobalTextualModelSearchQuery(
            ELEMENT_NAME_VALUATION_BEGINING_WITH_A,
            scope,
            EcorePackage.eNS_URI
    );
 
//
// Run the query with Eclise Search infrastructure in backgroud.
// Using a progress monitor allows to cancel this query if executed
// in Eclipse UI & having acces to Job view.
//
query.run(new NullProgressMonitor());
 
ISearchResult result = query.getModelSearchResult();
 
if (result instanceof IModelSearchResult) {
    //
    // Model result is a match occurences hierarchical tree mixing matches leaves and intermediate parent nodes
    // In this case a vistor flatten leaves in a collection of match occurences
    //
    Collection<IModelResultEntry> resultEntries = ((IModelSearchResult)result).getResultsFlatenned();
    if (resultEntries.getSource() instanceof EObject) {
        //
        // User to process this occurence
        //
    }
}

//
// Non Case Sensitive Joker expression matching all text beginning with either 'a' or 'A'
//
private static final String ELEMENT_NAME_VALUATION_BEGINS_WITH_A = "A*";
 
//
// In this case IModelSearchScope associated to
// "org.eclipse.emf.search.ecoreSearchEngine" search engine
// will collect any files with *.ecore extension from the current
// workspace.
//
IModelSearchScope scope = 
    ModelSearchWorkspaceScopeFactory.getInstance().
        createModelSearchWorkspaceScope(
            "org.eclipse.emf.search.ecoreSearchEngine"
        );
 
//
// 1)
//
// Creates & launches a new query to apply on the whole workspace.
// This query will open any *.ecore collected in the
// IModelSearchScope built upper in the code.
//
// 2)
//
// Run the query with Eclise Search infrastructure in backgroud.
// Using a progress monitor allows to cancel this query if executed
// in Eclipse UI & having acces to Job view.
//
IModelSearchResult query = 
    EcoreTextualModelSearchQueryLauncheerHelper.getInstance().
        launchGlobalTextualModelSearchQuery(
            ELEMENT_NAME_VALUATION_BEGINING_WITH_A,
            scope,
            EcorePackage.eNS_URI
    );
 
//
//
query.run(new NullProgressMonitor());
 
ISearchResult result = query.getModelSearchResult();
 
if (result instanceof IModelSearchResult) {
    //
    // Model result is a match occurences hierarchical tree mixing matches leaves and intermediate parent nodes
    // In this case a vistor flatten leaves in a collection of match occurences
    //
    Collection<IModelResultEntry> resultEntries = ((IModelSearchResult)result).getResultsFlatenned();
    if (resultEntries.getSource() instanceof EObject) {
        //
        // User to process this occurence
        //
    }
}