koppor · koppor · Sep 3, 2020 · Sep 21, 2020 · Sep 21, 2020 · Sep 21, 2020
diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -253,6 +253,7 @@ Note that this project **does not** adhere to [Semantic Versioning](http://semve
 - We added support for the new Microsoft Edge browser in all platforms. [#7056](https://github.com/JabRef/jabref/pull/7056)
 - We reintroduced emacs/bash-like keybindings. [#6017](https://github.com/JabRef/jabref/issues/6017)
 - We added a feature to provide automated cross library search using a cross library query language. This provides support for the search step of systematic literature reviews (SLRs). [koppor#369](https://github.com/koppor/jabref/issues/369)
+- We added the possibility to find (and add) papers that cite or are cited by a given paper. [#6187](https://github.com/JabRef/jabref/issues/6187)
 
 ### Changed
 

diff --git a/docs/adr/0018-use-opencitationsApi-for-citationrelations.md b/docs/adr/0018-use-opencitationsApi-for-citationrelations.md
@@ -0,0 +1,21 @@
+# Use OpenCitations API for Citation-Relations Tab in the Entry Editor
+
+## Context and Problem Statement
+
+The JabRef-Software has an entry editor with multiple tabs. One of them is the "Citation Relations" tab, that offers the possibility to explore citation relations. In order to do so, JabRef queries an API, to get the related articles.
+
+## Considered Options
+
+* [OpenCitations](https://opencitations.net/index/api/v1)
+* [Citationgecko](http://citationgecko.com/)
+* [Yewno](https://www.yewno.com/discover)
+* [Openknowledgemaps](https://openknowledgemaps.org/)
+* [Wikicite](http://wikicite.org/)
+* [Scholarcy](https://www.scholarcy.com/)
+* [Dimensions.ai](https://www.dimensions.ai/dimensions-apis/)
+* [Springernature](https://www.springernature.com/gp/researchers/bookmetrix)
+* [Github: adsabs](https://github.com/adsabs/adsabs-dev-api)
+
+## Decision Outcome
+
+Chosen option: OpenCitations, because its easy to use and one receive results in JSON, that is easy to deal with. Furthermore most of the other options are graphical online tools that are not meant to be used as an API.
diff --git a/docs/advanced-reading/citationrelations/images/Activity.png b/docs/advanced-reading/citationrelations/images/Activity.png
diff --git a/docs/advanced-reading/citationrelations/images/ClassDiagram.png b/docs/advanced-reading/citationrelations/images/ClassDiagram.png
diff --git a/docs/advanced-reading/citationrelations/images/FetcherState.png b/docs/advanced-reading/citationrelations/images/FetcherState.png
diff --git a/docs/advanced-reading/citationrelations/images/StateTab.png b/docs/advanced-reading/citationrelations/images/StateTab.png
diff --git a/docs/advanced-reading/citationrelations/images/sequencediagram.png b/docs/advanced-reading/citationrelations/images/sequencediagram.png
diff --git a/docs/advanced-reading/citationrelations/requirements-citation-relations.md b/docs/advanced-reading/citationrelations/requirements-citation-relations.md
@@ -0,0 +1,219 @@
+# Specification Book
+
+| Version | Authors | Status | Date | Commentary |
+| ------- | ----- | ------ | ----- | --------- |
+|  0.1    |  Raphael Kreft| Abgeschlossen | 03.11.2020 | [Projectwebsite](https://unibas-marcelluethi.github.io/software-engineering/project/project-summary.html) , [JabRef Website](https://www.jabref.org/)|
+||Olivier Mattmann||||
+||Matias Carballo||||
+||Tim Bachmann||||
+
+This specification book captures the requirements of the extension/modification of JabRef, that takes place as a part of the course "Software Engineering" at the University of Basel. This project implements [**issue #6187 Add posibility to explore citation relations**](https://github.com/JabRef/jabref/issues/6187). It should implement a way to explore articles that cite or are cited by articles in the database.
+
+## 1. Vision and Goals
+
+* /V10/ JabRef users can explore and administrate relations between articles
+* /Z10/ JabRef users have the possibility to explore their own references and find articles that reference or are refered to by own articles
+* /Z20/ It is not a goal to change [Search related articles using Mr. DLib](https://docs.jabref.org/advanced/entryeditor#related-articles-tab)
+
+## 2. Stakeholder
+
+* JabRef Maintainer @koppor
+* JabRef Maintainer reviewing the pull request
+* Tutoren: Joe Zgraggen, Günes Aydin
+* Dozent: Marcel Lüthi
+* Project-Developers: Raphael Kreft, Olivier Mattmann, Matias Carballo, Tim Bachmann
+
+## 3. Conditions
+
+* /R10/ Scope of application: JabRef Software
+* /R20/ Target group: JabRef users
+* /R30/ Runs unattended as part of JabRef
+* /R40/ Used Software on the target machines: JabRef, Java, OS: Windows/Linux/macOS
+* /R50/ Software on the development systems: JabRef, Java, OS: depending on the developer Windows/Linux oder macOS
+* /R60/ Organisational marginal conditions: Given by [Projektrichtlinien](https://unibas-marcelluethi.github.io/software-engineering/project/project-summary.html)
+* /R70/ Documentation of changes and operational intructions in the way set by the course
+* /R80/ Development-interface 1: The extension is part of JabRef and must adapt to its [Ecosystem](https://devdocs.jabref.org/getting-into-the-code/code-howtos)
+* /R90/ Development-interface 2: The API that is used to get the citations: [Opencitaions API](https://opencitations.net/index/api/v1)
+
+## 4. Context and Overview
+
+* /K10/ [Opencitaions API](https://opencitations.net/index/api/v1), to search for published works that cite or are cited by a certain reference
+* /K20/ JabRef, where the extension is embedded
+
+## 5. Functional Requirements
+
+* /F10/ The extension must allow the user to find articles cited by the selected article
+* /F20/ The user should be able to use the entire functionality from the GUI
+* /F30/ The extension must allow users to find articles that cite the selected article
+* /F40/ The user should be informed, if no articles are found
+* /F50/ The user should be able to select found articles and to add them to the database via a button
+* /F60/ The user should be informed if there is no internet connection
+* /F70/ The extension must ensure that no articles are added to the database if they're already present. Articles will be grey and the buttons will be deactivated (/F50/)
+* /F80/ The extension must be reachable via a tab in the entry editor
+* /F90/ The user should be informed if it is not possible to add an article to the database (/F70/)
+* /F100/ The tab should be composed of a left and a right section
+* /F110/ The left section must implement the functionality described in /F30/ and must contain a list with the search results given by /F30/
+* /F120/ The right section must implement the functionality described in /F10/ and must contain a list with the search results given by /F10/
+* /F130/ Articles listed as search results should be displayed grouped below each other using JabRef Standards of WebSearch (/F110/ und /F120/)
+* /F140/ The search in /F110/ and /F120/ should be repeated by pressing the corresponding Refresh-Buttons
+* /F170/ The extension must ensure that the selected article contains the needed informations for executing the search (DOI-Nummer des Eintrags)
+* /F180/ If not enough information is available, the extension must inform the user via a message in the lower part of the screen
+* /F190/ The extension should save the search results if the user leaves the tab and show them again when the user returns (/F150/)
+* /F200/ The extension should search for citations using the Open Citations API (/R90/)
+* /F210/ The extensions should display search results correctly (/F130/), that have at least a title and author linked to their DOI-Number
+* /F230/ The left and right sections of the tab should be separated using a movable separator that is located in the middle by default (/F100/)
+* /F250/ The extension should inform the user about the progress of the search query in this way: (#current articles from total #total articles)
+* /F260/ The extension should display search results that only have a DOI-Number by that number (Secondary case of /F210/)
+* /F270/ The extension should, as soon as a search query is running, have a button to cancel below the progress indicator (/F250/)
+* /F280/ If an article is already part of the database, the user should be able to navigate to it by clicking the corresponding article
+* /F290/ It should be possible to activate and deactivate the entire functionality of the tab in the settings
+* /F300/ If the functionality is activated, the search should start automatically as soon as the user is on the tab
+
+## 6. Non-functional requirements
+
+### 6.1 Quality requirements
+
+
+| System quality  | very good | good | normal | non relevant |
+| ----------------| --------  | ---  | ------ | -------------|
+| Functionality   |     x     |      |        |              |
+| Reliability     |           |  x   |        |              |
+| Usability       |     x     |      |        |              |
+| Efficiency      |           |      |   x    |              |
+| Mantainability  |           |      |   x    |              |
+| Portability     |           |      |        |      x       |
+
+* /QB10/ All operations should be executable from the UI
+* /QB20/ All textelements of the extension should be available in english and german
+* /QE10/ The time it take for a search query to complete is dependent on the number of results: The user is informed about the progress
+* /QT10/ There should be test cases for the logic of the API use
+* /QT20/ There should be test cases for adding to the database
+
+### 6.2 Other
+
+* /N10/ If the tab is left (/F80/) to another tab in the same article the results should be saved
+* /N20/ If the tab is left (/F80/) to another article or the database is closed the results should not be saved
+
+## 7. Acceptance criteria
+
+* /A10/ The implemented extension offers the functionality of displaying a list of search results
+* /A20/ The implemented extension should be operable from the GUI
+* /A30/ Errors must not lead to program crashes and are displayed to the user
+* /A40/ The quality requirement /QE10/ is fulfilled
+* /A50/ The quality requirement /QB20/ is fulfilled
+* /A60/ The quality requirement /QT10/ is fulfilled
+* /A70/ The quality requirement /QT20/ is fulfilled
+
+## 8. Appendix
+
+## Appendix A. Use-cases
+
+### Use Case 1
+
+* Name: Finding the extension
+* Actors: *JabRef user, JabRef*
+* Preconditions:
+  * JabRef is running
+  * JabRef user has openned a database containing articles
+* Default procedure
+  * JabRef-user selects an articles
+  * The article menu opens in the lower part of JabRef
+  * The user selects the tab of the extension
+* Postcondition success: *The view of the extension in the article menu below the tab*
+* Postcondition failure: -
+
+### Use Case 2
+
+* Name: Search cited articles
+* Actors: *JabRef user, JabRef, API*
+* Preconditions:
+  * JabRef is running
+  * JabRef user has openned a database containing articles
+  * User has selected an article
+  * User is on the extension tab
+  * There are no problems connecting to the API
+* Default procedure
+  * User presses the search button in the left section of the tab
+  * JabRef checks if enough information is available for the search
+  * JabRef sends a query to the API and waits for a response
+* Postcondition success: *The search results are displayed as a list in the result section*
+* Postcondition failure: *An error message is shown to the user if not enough information for a search*
+
+### Use Case 3
+
+* Name: Search citing articles
+* Actors: *JabRef user, JabRef, API*
+* Preconditions:
+  * JabRef is running
+  * JabRef user has openned a database containing articles
+  * User has selected an article
+  * User is on the extension tab
+  * There are no problems connecting to the API
+* Default procedure:
+  * User presses the search button in the right section of the tab
+  * JabRef checks if enough information is available for the search
+  * JabRef sends a query to the API and waits for a response
+* Postcondition success: *The search results are displayed as a list in the result section*
+* Postcondition failure: *An error message is shown to the user if not enough information for a search*
+
+### Use Case 4
+
+* Name: Adding cited article
+* Actors: *JabRef user, JabRef*
+* Preconditions:
+  * List of cited articles must be present
+* Default procedure:
+  * User selects at least one article from the list
+  * Add button is pressed
+  * Check if article is already in database
+* Postcondition success: *Article is added to database*
+* Postcondition failure: *Article is not added to database*
+
+### Use Case 5
+
+* Name: Adding cited by article
+* Actors: *JabRef user, JabRef*
+* Preconditions:
+  * List of cited by articles must be present
+* Default procedure
+  * User selects at least one article from the list
+  * Add button is pressed
+  * Check if article is already in database
+* Postcondition success: *Article is added to database*
+* Postcondition failure: *Article is not added to database*
+
+### Use Case 6
+
+* Name: Start search offline
+* Actors: *JabRef user, JabRef*
+* Preconditions:
+  * At least one article in database
+  * There is no internet connection
+* Default procedure:
+  * Select article in database
+  * Open the extension tab in the article menu
+* Postcondition success: *The user is informed about missing internet connection, search can be restarted*
+
+### Use Case 7
+
+* Name: Navigation to cited article
+* Actors: *JabRef user, JabRef*
+* Preconditions:
+  * Cited article has to be in database
+  * Article in the list has a different color (already in database)
+* Default procedure:
+  * User is in the extension tab
+  * User clicks on the article
+* Postcondition success: *User is moved to the entry editor, list is updated*
+
+### Use Case 8
+
+* Name: Navigation to citing article
+* Actors: *JabRef user, JabRef*
+* Preconditions:
+  * Citin article has to be in database
+  * Article in the list has a different color (already in database)
+* Default procedure:
+  * User is in the extension tab
+  * User clicks on the article
+* Postcondition success: *User is moved to the entry editor, list is updated*
diff --git a/...dvanced-reading/citationrelations/technical-documentation-citation-relations.md b/...dvanced-reading/citationrelations/technical-documentation-citation-relations.md
@@ -0,0 +1,115 @@
+# Technical Documentation
+
+| Version | Projectname | Authors | Status | Date | Commentary |
+| ------- | ----------- | ------- | ------ | ----- | --------- |
+|  0.1    | Citation Relations | Raphael Kreft| In development | 06.11.2020 | [Projektwebseite](https://unibas-marcelluethi.github.io/software-engineering/project/project-summary.html) , [JabRef Website](https://www.jabref.org/)|
+|||Olivier Mattmann||||
+|||Matias Carballo||||
+|||Tim Bachmann||||
+
+## 1 Introduction
+
+## 1.1 Purpose
+
+This document proposes a technical solution to the specification described in the Specification book.
+
+**Target Group**:
+
+* Developers, specifically the authors of this document
+* JabRef Maintainer, specially @koppor
+
+## 1.2 Relations to other documents
+
+* [Specification Book](requirements-citation-relations.md)
+
+The Specification book describes the project, and specifies the requirements. It is the starting point for all following steps. The Glossary contains definitions of all important terms for the project. The architecture decisions document [MADR] (<https://github.com/adr/madr>) contains all important decisions about architecture and implementation of the project.
+
+## 2. System Overview
+
+The project "Citation Relations" is an extension to JabRef that is developed as part of the "Software Engineering" course at the University of Basel. The extension should make it possible for users to search for cited/citing articles, navigate the search results and import them into the Database
+
+## 3. Design goals
+
+* The design of the extension should be inserted into that of JabRef seamlessly
+* The design of the UI should be intuitive to users
+* The design of the extension should be easy to update
+* The design should deliver acceptable performance
+* The design should be easy to test
+
+## 4. System behaviour
+
+The extension can be used from a separate tab in the entry editor. The fuction of this extension can be activated and deactivated from this tab. If the extension is activated, citations will be searched for using the API when the user opens the tab. The articles our article cites will be shown in the left part of the tab. The articles that cite our article will be shown on the right side. The search results can be imported into our database via click.
+
+
+## 5. Design
+
+The following section describes the Mid-Level-Design of the extension using UML diagrams.
+
+## 5.1 Static
+
+Class Diagram of Citation Relations:
+
+![Image of Class Diagram of CitationRelations](images/ClassDiagram.png)
+
+### 5.2 Dynamic
+
+Sequence Diagram of Citation Relations:
+
+![Image of Sequence Diagram of CitationRelations](images/sequencediagram.png)
+
+Activity Diagram of Citation Relations:
+
+![Image of Activity Diagram of CitationRelations](images/Activity.png)
+
+State Diagram of CitationRelationTab:
+
+![Image of State Diagram of CitationRelationTab](images/StateTab.png)
+
+State Diagram of CitationRelationFetcher:
+
+![Image of State Diagram of CitationRelationFetcher](images/FetcherState.png)
+
+### 5.3 Logic
+
+The logical constraints are specified in this section
+
+* **DOI Nummer benötigt für die Suche**
+
+        context BibEntry inv: self.getField(StandardField.DOI) != NULL
+
+* **Article is not part of the list if already in Database**
+
+        context CitationRelationFetcher::performSearch():List<BibEntry>
+        pre: Database.entries.contains(fetchedEntry)
+        post: !(List<BibEntry>.contains(fetchedEntry))
+
+* **Article is part of the list if not in Database**
+
+        context CitationRelationFetcher::performSearch():List<BibEntry>        
+        pre: !(Database.entries.contains(fetchedEntry))     
+        post: List<BibEntry>.add(fetchedEntry)
+
+* **Privacy Dialog must be accepted for search to take place**
+
+        context CitationRelationTab::searchForRelations() inv: self.privacyDialogAccepted = true
+
+* **Searc with valid DOI-Number**
+
+        context CitationRelationFetcher::performSearch(BibEntry)        
+        pre: BibEntry.getField(StandardField.DOI) != NULL       
+        post: List<BibEntry>.notEmpty()
+
+* **Search with invalid DOI-Number**
+
+        context CitationRelationFetcher::performSearch(BibEntry):List<BibEntry>
+        pre: BibEntry.getField(StandardField.DOI) != NULL and BibEntry.getField(StandardField.DOI).wrongFormat()
+        post: List<BibEntry>.isEmpty()
+
+* **Fetcher Name**
+
+        context CitationRelationFetcher::getName()
+        post: self.name = "CitationRelationFetcher"
+
+* **CitationRelationFetcher needs SearchType**
+
+        context CitationRelationFetcher inv: self.SearchType != NULL