Wraps s3 client in cross regional client when enabled

[cenedhryn]

Motivation and Context

Users want cross region ability, but do not want or need to know implementation details, they just want to enable the feature. This change modifies the S3 client builder code to check if cross region is enabled and then wraps the regular client in the cross region client and returns it (as an S3Client/S3AsyncClient).

Modifications

• Adds a customization flag to point out where the logic for creating a composed S3 client is located
• Changes the builder logic to check the customization flag and if so, call the composing code instead of just returning the client
• Also refactors the builder code to make it more readable
• Adds a decorator utility that can do conditional transforms
• Adds S3 specific logic for creating a list of decorators for client construction and conditions on when to apply them, that are submitted to the decorator utility. Adds the cross region client to the list.

Testing

Unit and functional testing.

[joviegas]

Are other parameters required in the test ?
Is it possible to keep just clientComposerFactory in this test customization.config ?

[cenedhryn]

Removed some unused parameters

[joviegas]

Can we add some validator here using regex to match the expected fqcn pattern and error out if it fails to match the supported package patters ?

[cenedhryn]

It doesn't seem like we have any checks for similar parameters (fqcn). What do you suggest would be allowed namespace patterns?

[joviegas]

We can do it in future something like this

        String pattern = "^(?:[a-zA-Z_$][a-zA-Z\\d_$]*\\.)+[a-zA-Z_$][a-zA-Z\\d_$]*$";

        Validate.true(Pattern.matches(pattern, fqcnSuppliedUser) , "Class name is not fqcn");

[joviegas]

I appreciate the elegant utilization of the ConditionalDecorator, effectively incorporating the decorator pattern and lambda functions in this implementation.

I used String representation just to test for my understanding , you can add this test cases if you want.
Commenting just to save this test case in string form

import static org.assertj.core.api.Assertions.assertThat;
import java.util.*;
import org.junit.jupiter.api.Test;

public class ConditionalDecoratorTest {

    @Test
    void testStringDecoration() {
        StringComposer stringComposer = new StringComposer();
//      assertThat(stringComposer.composeString("test", star?, dollar?).getBaseString()).isEqualTo(Result);
        assertThat(stringComposer.composeString("test", false, false).getBaseString()).isEqualTo("test");
        assertThat(stringComposer.composeString("test", false, true).getBaseString()).isEqualTo("$test$");
        assertThat(stringComposer.composeString("test", true, false).getBaseString()).isEqualTo("*test*");
        assertThat(stringComposer.composeString("test", true, true).getBaseString()).isEqualTo("$*test*$");
    }

    class BaseString {
        String baseString;

        public BaseString(String baseString) {
            this.baseString = baseString;
        }

        protected String getBaseString() {
            return baseString;
        }
    }

    class DefaultString extends BaseString {
        private DefaultString(String baseString) {
            super(baseString);
        }
    }

    class StarDecorated extends BaseString {
        private StarDecorated(BaseString baseString) {
            super(baseString.getBaseString());
        }
        @Override
        public String getBaseString() {
            return "*" + baseString + "*";
        }
    }

    class DollarDecorated extends BaseString {
        private DollarDecorated(BaseString baseString) {
            super(baseString.getBaseString());
        }

        @Override
        public String getBaseString() {
            return "$" + baseString + "$";
        }
    }

    class StringComposer {
        public BaseString composeString(String base, boolean starDecorated, boolean dollarDecorated) {
            List<ConditionalDecorator<BaseString>> decorators = new ArrayList<>();
            decorators.add(ConditionalDecorator.create(testOne -> starDecorated, StarDecorated::new));
            decorators.add(ConditionalDecorator.create(testTwo -> dollarDecorated, DollarDecorated::new));
            return ConditionalDecorator.decorate(new DefaultString(base), decorators);
        }
    }
}

[cenedhryn]

Thanks!

[sonarqubecloud]

Kudos, SonarCloud Quality Gate passed!   

0 Bugs
0 Vulnerabilities
0 Security Hotspots
74 Code Smells

88.4% Coverage
1.8% Duplication