RFR: 6616245: NullPointerException when using JFileChooser with a custom FileView [v5]

[Alexey Ivanov]

On Mon, 10 Oct 2022 13:58:30 GMT, Tejesh R <tr at openjdk.org> wrote:

>> When a custom `FileView` is used and folder traversal is restricted to a particular directory NPE occurs when user tries to traverse/select other folders except traversable folder. This is caused because when user selects folder other than traversable, the traversal is rejected and hence no file is selected as `currentDirectory` of `JFileChooser`. When user tries to access the restricted folder second time, previous selected file check is failing because of NPE since `getFileChooser().getCurrentDirectory();` is null. To fix the issue, NPE check is added.
>
> Tejesh R has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Updated based on review comments

Changes requested by aivanov (Reviewer).

test/jdk/javax/swing/JFileChooser/FileViewNPETest.java line 35:

> 33: 
> 34: import javax.swing.filechooser.FileView;
> 35: import jdk.test.lib.Platform;

It's not used any more, please remove.

Leave one blank line after the last import and the following comment with the jtreg tags.

test/jdk/javax/swing/JFileChooser/FileViewNPETest.java line 42:

> 40:  * @requires (os.family == "windows" | os.family == "linux")
> 41:  * @library /java/awt/regtesthelpers /test/lib
> 42:  * @build PassFailJFrame jdk.test.lib.Platform

Suggestion:

 * @library /java/awt/regtesthelpers
 * @build PassFailJFrame


`Platform` class from `/test/lib` is not used any more.

test/jdk/javax/swing/JFileChooser/FileViewNPETest.java line 65:

> 63:         JFileChooser jfc;
> 64: 
> 65:         //Initialize the components

I believe the comment is redundant. Being placed before the instruction text, it's confusing. The method name `initialize` is self-explanatory.

test/jdk/javax/swing/JFileChooser/FileViewNPETest.java line 77:

> 75:                 3. If NPE occurs on second selection then test FAILS, else test
> 76:                  is PASS.
> 77:                 """;

I propose the following text:


                Instructions to Test:
                1. The traversable folder is set to the Documents folder,
                 if it exists, in the user's home folder, otherwise
                 it's the user's home. Other folders are non-traversable.
                2. When the file chooser appears on the screen, select any
                 non-traversable folder from "Look-In" combo box,
                 for example the user's folder or a folder above it.
                 (The folder will not be opened since it's non-traversable).
                3. Select the Documents folder again.
                4. If NullPointerException occurs in the step 3, click Fail,
                 otherwise click Pass.

It consistently uses _“folder”_, no mention of “directory”. It explains that the user's home could be the root of the traversable tree. The instructions use imperative to select either _Fail_ or _Pass_.

test/jdk/javax/swing/JFileChooser/FileViewNPETest.java line 81:

> 79:         passFailJFrame = new PassFailJFrame("Test Instructions", INSTRUCTIONS, 5L, 13, 40);
> 80:         jfc = new JFileChooser();
> 81:         String path = System.getProperty("user.home") + File.separator + "Documents";

Suggestion:


        String userHome = System.getProperty("user.home");
        String docs = userHome + File.separator + "Documents";
        String path = (new File(docs).exists()) ? docs : userHome;

This will make the test more robust, it can continue to run even if `Documents` folder does not exist.

test/jdk/javax/swing/JFileChooser/FileViewNPETest.java line 84:

> 82: 
> 83:         jfc.setCurrentDirectory(new File(path));
> 84:         jfc.setFileView(new CustomFileView(path));

Suggestion:

        jfc.setFileView(new CustomFileView(path));
        jfc.setControlButtonsAreShown(false);

Hide _Open_ and _Cancel_ buttons in the file chooser.

-------------

PR: https://git.openjdk.org/jdk/pull/10485