OAK-11571: commons: add Closer class (similar to Guava Closer)

[reschke]

Note

1b60437

which added tests for Guava Closer. The Oak implementation only was written after tests were there.

[github-actions]

Commit-Check ✔️

[reschke]

I believe all comments were based on misunderstandings about what Guava does; see again d254e8f which has the same tests running with Guava.

@thomasmueller - every time we instantiate a collection with a non-default size, readers of the code will ask themselves: why? and does it really matter here?

[reschke]

Things IMHO left to do:

• address some Sonar warnings
• improve Javadoc
• rename the completely confusingly named method rethrow() to rethrowOnClose() - not done, because I misunterstood the semantics
• bikeshed about the package name - any opinions here???

Note that once this is in (and used throughout); we can get rid of the entire Guava common.io package.

[mbaedke]

What about RuntimeExceptions (or any Throwable that is not an IOException)? If they are thrown from closeable.close(), they will not be catched, even if suppressExceptionsOnClose is true (see modified test in comment below).

[mbaedke]

    public void compareClosers() {
        // when rethrow was called, Exceptions that happened upon close will be swallowed

        com.google.common.io.Closer guavaCloser = com.google.common.io.Closer.create();
        Closer oakCloser = Closer.create();

        try {
            throw oakCloser.rethrow(new InterruptedException());
        } catch (Exception e) {}

        try {
            throw guavaCloser.rethrow(new InterruptedException());
        } catch (Exception e) {}

        try {
            oakCloser.register(() -> { throw new RuntimeException(); });
            oakCloser.close();
        } catch (Exception e) {
            fail("should not throw but got: " + e);
        }

        try {
            guavaCloser.register(() -> { throw new RuntimeException(); });
            guavaCloser.close();
        } catch (Exception e) {
            fail("should not throw but got: " + e);
        }
    }

would currently fail.

[mbaedke]

RuntimeException are not yet treated correctly, see inline comments.

[sonarqubecloud]

Quality Gate passed

Issues
7 New issues
0 Accepted issues

Measures
0 Security Hotspots
89.8% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud