@ConditionalOnProperty

Reference: Spring Docs - @ConditionalOnProperty

What is @ConditionalOnProperty?

• A conditional annotation used in the Spring Framework to specify conditions under which a Bean is created or configured

• Can determine whether to create a Bean based on the presence or value of a specific property

Attributes of @ConditionalOnProperty

@Retention(RetentionPolicy.RUNTIME)
@Target({ ElementType.TYPE, ElementType.METHOD })
@Documented
@Conditional(OnPropertyCondition.class)
public @interface ConditionalOnProperty {

    /**
     * Alias for {@link #name()}.
     * @return the names
     */
    String[] value() default {};

    /**
     * A prefix that should be applied to each property. The prefix automatically ends
     * with a dot if not specified. A valid prefix is defined by one or more words
     * separated with dots (e.g. {@code "acme.system.feature"}).
     * @return the prefix
     */
    String prefix() default "";

    /**
     * The name of the properties to test. If a prefix has been defined, it is applied to
     * compute the full key of each property. For instance if the prefix is
     * {@code app.config} and one value is {@code my-value}, the full key would be
     * {@code app.config.my-value}
     * <p>
     * Use the dashed notation to specify each property, that is all lower case with a "-"
     * to separate words (e.g. {@code my-long-property}).
     * @return the names
     */
    String[] name() default {};

    /**
     * The string representation of the expected value for the properties. If not
     * specified, the property must <strong>not</strong> be equal to {@code false}.
     * @return the expected value
     */
    String havingValue() default "";

    /**
     * Specify if the condition should match if the property is not set. Defaults to
     * {@code false}.
     * @return if the condition should match if the property is missing
     */
    boolean matchIfMissing() default false;

}

Default value

• The property exists in the Environment, and

• is not false

Optional Elements

• name (required attribute) - String[]

  • Specifies the name of the property to test

• havingValue - String

  • Specifies the attribute that the property should have

    • Specifies a value to compare with the property value!

  • Can be used optionally, with a default value of empty string ("")

  • If this value is not specified or created as an empty string, the Bean is created as long as the property is set, regardless of the property value

  • If a value is specified (not empty string), the Bean is created only when the specified value matches the property value

• matchIfMissing - boolean

  • Determines whether the condition is satisfied when the property does not exist in the Environment at all

  • Default value is false, and the Bean is not created if the property is not set

  • When set to true, the Bean is created even if the property is not set

• prefix - String

  • Specifies a prefix to apply to each property

  • This attribute allows specifying conditions using a common prefix for multiple properties

• value - String[]

  • Alias for name()