This post demonstrates how to use the @Conditional annotation which is the workhorse of Spring Boot’s automatic configuration. You may also use this technique in your own codes.

First, there was @Profile

@Profile annotation allows for the registration of multiple beans of the same type and associate them to one or more profiles. When you run your application, you make one or more profiles active by

Listing them as comma-delimited string value in applications.properties file, e.g.,
spring.profiles.active=Profile1,PH,CN,MY
1
spring.profiles.active=Profile1,PH,CN,MY

Listing them as comma-delimited string value in web.xml (for web applications), e.g.,

<!-- Lines above omitted for brevity -->
<context-param>
    <param-name>spring.profiles.active</param-name>
    <param-value>Profile1,PH</param-value>
</context-param>
<!-- Lines below omitted for brevity -->

<context-param>

<param-name>spring.profiles.active</param-name>

<param-value>Profile1,PH</param-value>

</context-param>

Listing them as a System property
-Dspring.profiles.active=MY,CN
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-Dspring.profiles.active=MY,CN

As you can see, there is no “intelligence” applied with @Profile.

Then came @Conditional

Spring introduced the @Conditional annotation in Spring 4 which allows for registration of beans conditionally based on any arbitrary condition.

Yes, in any arbitrary condition like whether or not Today is a public holiday!

Typical conditions to check

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These are typically the conditions you want to base your bean creation on

whether or not a specific class is present in the classpath
whether or not a specific file exists on a location
whether or not a specific property value is configured in a configuration file
whether or not a system property value is available

The Condition Interface

Using @Conditional starts with the Condition interface:

org.springframework.context.annotation.Condition

1	org.springframework.context.annotation.Condition

It is an interface with a single method.

Sample Condition

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package com.turreta.springboot.conditional;

import org.springframework.context.annotation.Condition;
import org.springframework.context.annotation.ConditionContext;
import org.springframework.core.type.AnnotatedTypeMetadata;

import java.time.DayOfWeek;
import java.time.LocalDate;

public class IsTodayFridayCondition implements Condition {
    @Override
    public boolean matches(ConditionContext context, AnnotatedTypeMetadata metadata) {

        /**
         * Is Today Friday?
         */
        LocalDate ld = LocalDate.now();
        DayOfWeek dow = ld.getDayOfWeek();
        return DayOfWeek.FRIDAY == dow;
    }
}

package com.turreta.springboot.conditional;

import org.springframework.context.annotation.Condition;

import org.springframework.context.annotation.ConditionContext;

import org.springframework.core.type.AnnotatedTypeMetadata;

import java.time.DayOfWeek;

import java.time.LocalDate;

public class IsTodayFridayCondition implements Condition {

@Override

public boolean matches(ConditionContext context, AnnotatedTypeMetadata metadata) {

/**

* Is Today Friday?

LocalDate ld = LocalDate.now();

DayOfWeek dow = ld.getDayOfWeek();

return DayOfWeek.FRIDAY == dow;

}

Let’s create a Spring Boot Application

Let’s create a new Spring Boot Application using IntelliJ (optional) and Spring Initialzr (or http://start.spring.io/).

Step 1: Create a new project

Choose Spring Initialzr. Then click Next.

Step 2: Provide project information

Step 3: Choose nothing

Step 4: Save the new project

Step 5: Create our conditions

IsTodayFridayCondition class

This class checks whether or not Today is Friday.

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package com.turreta.springboot.conditional;

import org.springframework.context.annotation.Condition;
import org.springframework.context.annotation.ConditionContext;
import org.springframework.core.type.AnnotatedTypeMetadata;

import java.time.DayOfWeek;
import java.time.LocalDate;

public class IsTodayFridayCondition implements Condition {
    @Override
    public boolean matches(ConditionContext context, AnnotatedTypeMetadata metadata) {

        /**
         * Is Today Friday?
         */
        LocalDate ld = LocalDate.now();
        DayOfWeek dow = ld.getDayOfWeek();
        return DayOfWeek.FRIDAY == dow;
    }
}

package com.turreta.springboot.conditional;

import org.springframework.context.annotation.Condition;

import org.springframework.context.annotation.ConditionContext;

import org.springframework.core.type.AnnotatedTypeMetadata;

import java.time.DayOfWeek;

import java.time.LocalDate;

public class IsTodayFridayCondition implements Condition {

@Override

public boolean matches(ConditionContext context, AnnotatedTypeMetadata metadata) {

/**

* Is Today Friday?

LocalDate ld = LocalDate.now();

DayOfWeek dow = ld.getDayOfWeek();

return DayOfWeek.FRIDAY == dow;

}

ActiveEveryDayCondition class

This just makes the associated beans active everyday.

package com.turreta.springboot.conditional;

import org.springframework.context.annotation.Condition;
import org.springframework.context.annotation.ConditionContext;
import org.springframework.core.type.AnnotatedTypeMetadata;

public class ActiveEveryDayCondition implements Condition {
    @Override
    public boolean matches(ConditionContext context, AnnotatedTypeMetadata metadata) {
        return true;
    }
}

package com.turreta.springboot.conditional;

import org.springframework.context.annotation.Condition;

import org.springframework.context.annotation.ConditionContext;

import org.springframework.core.type.AnnotatedTypeMetadata;

public class ActiveEveryDayCondition implements Condition {

@Override

public boolean matches(ConditionContext context, AnnotatedTypeMetadata metadata) {

return true;

}

Step 6: Create our configuration class

POJOs needed

These are the classes needed for our configuration class.

EveryDayBean class

package com.turreta.springboot.conditional;

public class EveryDayBean {
}

package com.turreta.springboot.conditional;

public class EveryDayBean {

}

FridayOnlyBean class

package com.turreta.springboot.conditional;

public class FridayOnlyBean {
}

package com.turreta.springboot.conditional;

public class FridayOnlyBean {

}

MyConfig class

Here we used the @Conditional annotation for each @Bean

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package com.turreta.springboot.conditional;

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Conditional;
import org.springframework.context.annotation.Configuration;

@Configuration
public class MyConfig {

    @Bean
    @Conditional(IsTodayFridayCondition.class)
    public FridayOnlyBean createFridayOnlyBean() {
        return new FridayOnlyBean();
    }

    @Bean
    @Conditional(ActiveEveryDayCondition.class)
    public EveryDayBean createEveryDayBean() {
        return new EveryDayBean();
    }
}

package com.turreta.springboot.conditional;

import org.springframework.context.annotation.Bean;

import org.springframework.context.annotation.Conditional;

import org.springframework.context.annotation.Configuration;

@Configuration

public class MyConfig {

@Bean

@Conditional(IsTodayFridayCondition.class)

public FridayOnlyBean createFridayOnlyBean() {

return new FridayOnlyBean();

}

@Bean

@Conditional(ActiveEveryDayCondition.class)

public EveryDayBean createEveryDayBean() {

return new EveryDayBean();

}

Step 7: Test our codes

You may download all the codes from the link provided at the very bottom section.

Unit Test Output

Download the Codes

https://github.com/Turreta/Spring-Boot-How-to-use-Conditional-in-your-own-codes

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First, there was @Profile

Then came @Conditional

Typical conditions to check

The Condition Interface

Sample Condition

Let’s create a Spring Boot Application

Step 1: Create a new project

Step 2: Provide project information

Step 3: Choose nothing

Step 4: Save the new project

Step 5: Create our conditions

IsTodayFridayCondition class

ActiveEveryDayCondition class

Step 6: Create our configuration class

POJOs needed

EveryDayBean class

FridayOnlyBean class

MyConfig class

Step 7: Test our codes

Unit Test Output

Download the Codes

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