Conditional Configuration

Conditional by Property

If the property matches the defined value then the configuration is applied.

@Configuration
@ConditionalOnProperty(name = "property.name", matchIfMissing = false, havingValue = "true")
public class ConfigClass

Argument	Usage
havingValue	The value required to activate the condition
matchIfMissing	If true, the condition activates when the property is not defined

Conditional by Condition Class

When the condition returns true then the configuration is applied.

@Configuration
@Conditional(ConfigurationCondition.class)
public class ConfigClass

public class ConfigurationCondition implements Condition
{

   @Override
   public boolean matches(final ConditionContext context, final AnnotatedTypeMetadata metadata)
   {
      // Code
   }

}

Conditional by Bean

The bean is loaded only if the referenced bean has been loaded:

@Bean
@ConditionalOnBean(name="mainBean")
public Component component(){
   return new Component();
}

The bean is loaded only if the referenced bean has NOT been loaded:

@Bean
@ConditionalOnMissingBean(name="mainBean")
public Placeholder placeholder(){
   return new Placeholder();
}

Conditional by Class

The bean is loaded only if the class is in the classpath:

@Bean
@ConditionalOnClass(name="com.path.Driver")
public Driver driver(){
   return new Driver();
}

The bean is loaded only if the class is missing from the classpath:

@Bean
@ConditionalOnMissingClass(name="com.path.Driver")
public AnotherDriver driver(){
   return new AnotherDriver ();
}