ConditionalOnPropertiesPresent - Spring Boot custom conditional example

ConditionalOnPropertiesPresent.java

package foo;

import org.springframework.context.annotation.Conditional;

import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;

@Conditional(OnPropertiesPresentCondition.class)
@Retention(RetentionPolicy.RUNTIME)
@Target({ ElementType.TYPE, ElementType.METHOD })
public @interface ConditionalOnPropertiesPresent {
    String[] value() default {};
}

OnPropertiesPresentCondition.java

import org.springframework.boot.autoconfigure.condition.ConditionOutcome;
import org.springframework.boot.autoconfigure.condition.SpringBootCondition;
import org.springframework.context.annotation.ConditionContext;
import org.springframework.core.type.AnnotatedTypeMetadata;

public class OnPropertiesPresentCondition extends SpringBootCondition {
    @Override public ConditionOutcome getMatchOutcome(ConditionContext context, AnnotatedTypeMetadata metadata) {
        String[] properties = (String[]) metadata.getAnnotationAttributes(
                ConditionalOnPropertiesPresent.class.getName()).get("value");

        ConditionOutcome conditionOutcome = ConditionOutcome.match();

        for (String property : properties) {
            if (!context.getEnvironment().containsProperty(property)) {
                conditionOutcome = ConditionOutcome.noMatch("Required property " + property + " not found");
                break;
            }
        }

        return conditionOutcome;
    }
}