63 lines
2.2 KiB
Markdown
63 lines
2.2 KiB
Markdown
---
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nav_order: 26
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parent: Decision Records
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---
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# Use Java Native Access to Determine Default Directory
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## Context and Problem Statement
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JabRef needs to propose a file directory to a user for storing files.
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How to determine the "best" directory native for the OS the user runs.
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## Decision Drivers
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* Low maintenance effort
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* Follow JabRef's architectural guidelines
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* No additional dependencies
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## Considered Options
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* Use Swing's FileChooser to Determine Default Directory
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* Use `user.home`
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* [AppDirs](https://github.com/harawata/appdirs)
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* [Java Native Access](https://github.com/java-native-access/jna)
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## Decision Outcome
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Chosen option: "Java Native Access", because comes out best (see below).
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## Pros and Cons of the Options
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### Use Swing's FileChooser to Determine Default Directory
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Swing's FileChooser implemented a very decent directory determination algorithm.
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It thereby uses `sun.awt.shell.ShellFolder`.
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* Good, because provides best results on most platforms.
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* Good, because also supports localization of the folder name. E.g., `~/Dokumente` in Germany.
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* Bad, because introduces a dependency on Swing and thereby contradicts the second decision driver.
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* Bad, because GraalVM's support Swing is experimental.
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* Bad, because handles localization only on Windows.
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### Use `user.home`
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There is `System.getProperty("user.home");`.
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* Bad, because "The concept of a HOME directory seems to be a bit vague when it comes to Windows". See <https://stackoverflow.com/a/586917/873282> for details.
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* Bad, because it does not include `Documents`:
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As of 2022, `System.getProperty("user.home")` returns `c:\Users\USERNAME` on Windows 10, whereas
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`FileSystemView` returns `C:\Users\USERNAME\Documents`, which is the "better" directory.
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### AppDirs
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> AppDirs is a small java library which provides a path to the platform dependent special folder/directory.
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* Good, because already used in JabRef.
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* Bad, because does not use `Documents` on Windows, but rather `C:\Users\<Account>\AppData\<AppAuthor>\<AppName>` as basis.
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### Java Native Access
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* Good, because no additional dependency required, as it is already loaded by AppDirs.
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* Good, because it is well maintained and widely used.
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* Good, because it provides direct access to `Documents` and other system variables.
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