EMF Search---Developer Guide

Introduction

Developers have several levels/contexts/persitences 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 perstistence layer type
  • Eclipse Resources
  • Local File System
  • WWW distant resources (Close to be supported)
  • DB persitence (Support planned)

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

Search Scope & Visitors

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();
    }

• Eclipse Workspace resource

• Local File System

• Distant locations (Http URIs)

• EE repositories

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
//
IModelSearchResult 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
        //
    }
}