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Difference between revisions of "EMF DiffMerge"

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== Introduction  ==
 
== Introduction  ==
  
EMF Diff/Merge provides a lightweight engine for comparing and merging models using IDs. Its scope includes, among others:  
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[[Image:Logo EDM Small.png]]
  
*2-way and 3-way comparison of arbitrary EMF models (or "instance models").  
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EMF Diff/Merge is a tool for merging models. More precisely, it is a technical component which helps create tools that need to merge models. It consists in a diff/merge engine that is designed to prevent data loss and enforce model consistency during merge, thanks to consistency rules - predefined and, if needed, user-defined. It also includes GUI components.  
*Matching of model elements by ID, where an ID can be any "signature" that uniquely identifies the element within its scope: Ecore ID, XML ID, qualified name, location in model tree, etc.  
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*A simple GUI with reusable UI components.
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The tool is intended to satisfy the following requirements:
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It is intended to be a booster for developing merge-based features or systems such as model refactoring, iterative model transformations, bridges between models or modeling tools, collaborative modeling environments, or versioning systems.
  
*It must realistically support the comparison and merge of large models. There is thus an emphasis on scalability and reliability.  
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The EMF Diff/Merge project is part of [http://www.eclipse.org/projects/project.php?id=modeling.emf EMF]
*The consistency of the model being merged must be preserved by the tool whenever possible, by automatically merging interdependent differences together.  
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*The order in which differences are merged must have no impact.
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The final goal is to obtain a mature, versatile software building block for multiple usages: version control, incremental model transformations, model refactoring, etc.<br>
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== Context and issues  ==
  
The EMF Diff/Merge project is part of [http://www.eclipse.org/projects/project.php?id=modeling.emf EMF].<br>
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Merging models is a common need in model-based activities, not only for version control of models but for model manipulation in general. However, it is a much more complex operation than merging source code. This is because models, in the EMF sense, are rich data structures constrained by a metamodel and sometimes subject to implicit engineering rules.&nbsp;Have you ever merged models in the past and obtained incorrect, unexpected or inconsistent results?&nbsp;This is what EMF Diff/Merge seeks to prevent.
 +
 
 +
== Tool overview  ==
 +
 
 +
[[Image:ReducedOverview.png|center]]
 +
 
 +
The scope of EMF Diff/Merge covers:
 +
 
 +
*A lightweight, configurable engine for comparing and merging EMF-based models in 2-way and 3-way (with common ancestor) configurations.
 +
 
 +
*Matching of model elements by ID, where an ID can be any "signature" that uniquely identifies the element within its scope: Ecore ID, XML ID, qualified name, location in model tree, etc.
 +
 
 +
*A GUI with reusable components.
 +
 
 +
Among others, the tool exhibits the following characteristics:
 +
 
 +
*Comparison can be performed on any arbitrary model scope for versatility and scalability reasons.
 +
 
 +
*Interdependent differences are merged together in order to preserve model consistency.
 +
 
 +
*The order in which differences are merged has no impact.
 +
 
 +
*The global impact of a merge can be determined beforehand (picture above).
 +
 
 +
*Undo/redo of merges is supported.
 +
 
 +
== Principle of the solution  ==
 +
 
 +
The usage process is illustrated by the figure below. First, a comparison is created based on the models to compare. The differences between those models are computed according to given policies. Then, as long as differences remain, any subset of these differences can be selected for merging. Every time, predefined consistency rules and user-defined policies are used to compute the minimal superset of differences that must be merged to preserve consistency. The user may decide whether to confirm or cancel the merge of the whole set of differences.
 +
 
 +
<br> [[Image:Process.png|center]]
 +
 
 +
For a description on how the objectives and the level of abstraction differ from EMF Compare, see the [http://www.eclipse.org/proposals/modeling.emf.edm/ project proposal].  
  
 
== Usage  ==
 
== Usage  ==
  
 
*[http://wiki.eclipse.org/EMF_DiffMerge/Programmatic_Usage Programmatic usage and concepts]  
 
*[http://wiki.eclipse.org/EMF_DiffMerge/Programmatic_Usage Programmatic usage and concepts]  
*[http://wiki.eclipse.org/EMF_DiffMerge/Default_GUI Default GUI]<br>
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*[http://wiki.eclipse.org/EMF_DiffMerge/Default_GUI Default GUI]  
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*[https://hudson.eclipse.org/hudson/job/buckminster-emf-diffmerge-master/javadoc/ Javadoc]
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== Documents  ==
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 +
*[http://wiki.eclipse.org/images/4/4c/EDM_ECE12.pdf Overview] at EclipseCon Europe 2012 - Modeling Symposium
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*[http://jaxenter.com/introducing-emf-diff-merge-chat-with-olivier-constant-project-lead-47666.html "New in Kepler" interview] in June 2013 on JAXenter
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*[http://wiki.eclipse.org/images/f/fc/EDM_KeplerDemoCamp_Frankfurt_2013.pdf Presentation] at Kepler Demo Camp Frankfurt am Main
 +
 
 +
== Download  ==
 +
 
 +
Click here for the [http://wiki.eclipse.org/EMF_DiffMerge/Download Download page].
 +
 
 +
== Links  ==
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 +
*[http://www.eclipse.org/projects/project.php?id=modeling.emf.diffmerge Project summary]: a summary of the current state of the project
 +
 
 +
*[http://eclipse.org/diffmerge/ Project homepage]: the standard Eclipse web page for the project, essentially referring to this wiki
 +
 
 +
*[http://www.eclipse.org/proposals/modeling.emf.edm/ Project proposal]: the original proposal for the project
 +
 
 +
*[http://www.eclipse.org/forums/index.php?t=thread&frm_id=246 Forum]: the dedicated newsgroup
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 +
*[https://bugs.eclipse.org/bugs/buglist.cgi?list_id=2354424;classification=Modeling;query_format=advanced;component=Core;component=UI;component=Patterns;product=EMF.Diffmerge Bugzilla]: for reporting bugs
 +
 
 +
*[http://git.eclipse.org/c/diffmerge/org.eclipse.emf.diffmerge.core.git/ Source repository]: the git repository of source files
  
== Links<br>  ==
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*[https://git.eclipse.org/r/#/admin/projects/diffmerge/org.eclipse.emf.diffmerge.core Gerrit access]: the project on Eclipse Gerrit
  
*[http://www.eclipse.org/projects/project.php?id=modeling.emf.diffmerge Project summary]: a summary of the current state of the project
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*Build jobs: [https://hudson.eclipse.org/hudson/job/buckminster-emf-diffmerge-master/ main], [https://hudson.eclipse.org/hudson/job/buckminster-emf-diffmerge-helios/ legacy]
*[http://www.eclipse.org/proposals/modeling.emf.edm/ Project proposal]: the original proposal that led to the creation of the project
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*[http://www.eclipse.org/forums/index.php?t=thread&frm_id=246 Forum]: the dedicated newsgroup
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*[https://bugs.eclipse.org/bugs/buglist.cgi?list_id=2354424;classification=Modeling;query_format=advanced;component=Core;component=UI;product=EMF.Diffmerge Bugzilla]: for reporting bugs
+

Revision as of 11:54, 26 August 2014

Introduction

Logo EDM Small.png

EMF Diff/Merge is a tool for merging models. More precisely, it is a technical component which helps create tools that need to merge models. It consists in a diff/merge engine that is designed to prevent data loss and enforce model consistency during merge, thanks to consistency rules - predefined and, if needed, user-defined. It also includes GUI components.

It is intended to be a booster for developing merge-based features or systems such as model refactoring, iterative model transformations, bridges between models or modeling tools, collaborative modeling environments, or versioning systems.

The EMF Diff/Merge project is part of EMF

Context and issues

Merging models is a common need in model-based activities, not only for version control of models but for model manipulation in general. However, it is a much more complex operation than merging source code. This is because models, in the EMF sense, are rich data structures constrained by a metamodel and sometimes subject to implicit engineering rules. Have you ever merged models in the past and obtained incorrect, unexpected or inconsistent results? This is what EMF Diff/Merge seeks to prevent.

Tool overview

ReducedOverview.png

The scope of EMF Diff/Merge covers:

  • A lightweight, configurable engine for comparing and merging EMF-based models in 2-way and 3-way (with common ancestor) configurations.
  • Matching of model elements by ID, where an ID can be any "signature" that uniquely identifies the element within its scope: Ecore ID, XML ID, qualified name, location in model tree, etc.
  • A GUI with reusable components.

Among others, the tool exhibits the following characteristics:

  • Comparison can be performed on any arbitrary model scope for versatility and scalability reasons.
  • Interdependent differences are merged together in order to preserve model consistency.
  • The order in which differences are merged has no impact.
  • The global impact of a merge can be determined beforehand (picture above).
  • Undo/redo of merges is supported.

Principle of the solution

The usage process is illustrated by the figure below. First, a comparison is created based on the models to compare. The differences between those models are computed according to given policies. Then, as long as differences remain, any subset of these differences can be selected for merging. Every time, predefined consistency rules and user-defined policies are used to compute the minimal superset of differences that must be merged to preserve consistency. The user may decide whether to confirm or cancel the merge of the whole set of differences.


Process.png

For a description on how the objectives and the level of abstraction differ from EMF Compare, see the project proposal.

Usage

Documents

Download

Click here for the Download page.

Links

  • Project homepage: the standard Eclipse web page for the project, essentially referring to this wiki
  • Forum: the dedicated newsgroup

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