EMF Search will provide the fundamental infrastructure and components for search queries on EMF based models. A particular focus is made on integration with the Eclipse Core Search API for end user tight integration.
EMF Search is an Ecore meta-model based extensible search engine which purpose is to provide users query launching services against Ecore based models.
Meta-model based search is basically being able to take advantage of a meta-model structure to run generic search queries onto it. This means that a meta-model structure, defining a minimal modeling "organizaton", contains information enough to get operations applied to it, and by extension having same operations applied to any inheriting model compliant with this meta-model structure. Ecore based search is in fact a particular case of meta-model based treatment, a typical approach also known as Model Driven Architecture.
In other words, this allows to develop meta-model based generic algorithms, valid across any user defined model extending elements & structure of a given meta-model. Such technics are usually employed as part of a code generation developement process also known as Model Driven Development, allowing developers to code things once, setting up templates based code generation getting its data from the particular valuation of an instance of a given meta-model (eg: An actual user defined model or domain model populated with pertinent data).
(see also EMF : Eclipse Modeling Framework).
For model search explanatory purposes, we need to introduce some terminology. First at all, lets keep in mind a model search query always need to deal with entities such as a scope of model resource(s)/element(s) onto which a search query will apply, a set of participant meta-elements which the search query will consider, and finally a search query, textual, scriptical,programatic which an associated model search engine will evaluate against a scope and participants. This evaluation obviously having the role to produce Model Search Results.
This brief explanation just made main concepts appearing : Model Search Scope, Model Search Participants, Model Search Query, Model Search Engine, Model Search Results.
EMF Search has extension point allowing user to contribute custom model search engines (see org.eclipse.emf.search.modelSearchEngine extension point definition). A model search engine has responsability, given a model resource scope, to evaluate a model search query applying only on a set of selected meta-elements (called meta-elements participants).
EMF Search offers extensible model search queries mechanism. Users can contribute model search queries potentially combined with any numbers of diferent elements particpants. (eg. given the fact different user efined elements extends Ecore meta-elements). As a result, users can register to org.eclipse.emf.search.modelSearchID extension their own model search queries (plus the way to handle it from UI point of view) and the, associating it to an existing model search engine.
EMF Search offers extensible model search participants elements mechanism. Users can contribute model search participants potentially combined with any numbers of diferent model search queries. As a result, users can register to org.eclipse.emf.search.modelSearchParticipantTab extension their own model search participant elements (plus the way to handle it from UI point of view) and, associating it to an existing model search engine.
Model Search Scope stands for a set of ecore resources to be considerer by the search query. We can make a comparison with platform search concepts from the scope point of view. As in the text search or java search, user can search into the whole workspace or reduce its scope to selected resources, selected projects or even given working set.
Query evaluation produces matches, being collected in a result object or each resource evaluated. Matches can be considered as reult entries of top level reult object. These matches are considered as Model Search Result and will populate the Eclipse Search View.
EMF Model search integration is available by Ctrl+H shortcut. It pops up the Eclipse search dialog with an additional "modeling" tab.
