DZone
Thanks for visiting DZone today,
Edit Profile
  • Manage Email Subscriptions
  • How to Post to DZone
  • Article Submission Guidelines
Sign Out View Profile
  • Post an Article
  • Manage My Drafts
Over 2 million developers have joined DZone.
Log In / Join
Refcards Trend Reports Events Over 2 million developers have joined DZone. Join Today! Thanks for visiting DZone today,
Edit Profile Manage Email Subscriptions Moderation Admin Console How to Post to DZone Article Submission Guidelines
View Profile
Sign Out
Refcards
Trend Reports
Events
Zones
Culture and Methodologies Agile Career Development Methodologies Team Management
Data Engineering AI/ML Big Data Data Databases IoT
Software Design and Architecture Cloud Architecture Containers Integration Microservices Performance Security
Coding Frameworks Java JavaScript Languages Tools
Testing, Deployment, and Maintenance Deployment DevOps and CI/CD Maintenance Monitoring and Observability Testing, Tools, and Frameworks
Partner Zones AWS Cloud
by AWS Developer Relations
Culture and Methodologies
Agile Career Development Methodologies Team Management
Data Engineering
AI/ML Big Data Data Databases IoT
Software Design and Architecture
Cloud Architecture Containers Integration Microservices Performance Security
Coding
Frameworks Java JavaScript Languages Tools
Testing, Deployment, and Maintenance
Deployment DevOps and CI/CD Maintenance Monitoring and Observability Testing, Tools, and Frameworks
Partner Zones
AWS Cloud
by AWS Developer Relations
Building Scalable Real-Time Apps with AstraDB and Vaadin
Register Now

Trending

  • Micro Frontends on Monorepo With Remote State Management
  • Fun Is the Glue That Makes Everything Stick, Also the OCP
  • Working on an Unfamiliar Codebase
  • Integration Architecture Guiding Principles, A Reference

Trending

  • Micro Frontends on Monorepo With Remote State Management
  • Fun Is the Glue That Makes Everything Stick, Also the OCP
  • Working on an Unfamiliar Codebase
  • Integration Architecture Guiding Principles, A Reference
  1. DZone
  2. Coding
  3. Languages
  4. Grails Goodness: Conditionally Load Beans in Java Configuration Based on Grails Environment

Grails Goodness: Conditionally Load Beans in Java Configuration Based on Grails Environment

Hubert Klein Ikkink user avatar by
Hubert Klein Ikkink
·
Aug. 08, 14 · Interview
Like (0)
Save
Tweet
Share
5.96K Views

Join the DZone community and get the full member experience.

Join For Free

In a previous post we saw that we can use Spring's Java configuration feature to load beans in our Grails application. We can use the @Profile annotation to conditionally load beans based on the currently active Spring profile. We can for example use the Java system property spring.profiles.active when we start the Grails application to make a profile active. But wouldn't it be nice if we could use the Grails environment setting to conditionally load beans from a Java configuration?

It turns out this is not so hard to achieve. We must implement the matches method from the Condition interface from the org.springframework.context.annotation package. Next we create a new annotation interface where we delegate basically to our implementation class.

Let's start with writing an implementation for the Condition interface:

// File: src/groovy/com/mrhaki/grails/context/annotation/GrailsEnvCondition.groovy
package com.mrhaki.grails.context.annotation

import grails.util.Environment
import org.springframework.context.annotation.Condition
import org.springframework.context.annotation.ConditionContext
import org.springframework.core.type.AnnotatedTypeMetadata
import org.springframework.util.Assert
import org.springframework.util.MultiValueMap

/**
 * <p>{@link Condition} that matches based on the value of
 * a {@link GrailsEnv @GrailsEnv} annotation.</p>
 *
 * <p>The value of the current Grails environment is compared to given
 * Grails environments set via the {@link GrailsEnv @GrailsEnv} annotation.</p>
 *
 * @author Hubert A. Klein Ikkink aka mrhaki
 * @see GrailsEnv
 */
class GrailsEnvCondition implements Condition {

    @Override
    public boolean matches(final ConditionContext context, final AnnotatedTypeMetadata metadata) {
        final MultiValueMap<String, Object> attributes = metadata.getAllAnnotationAttributes(GrailsEnv.class.name)
        if (attributes != null) {
            final List<String> value = attributes.get('value')
            return value ? value.any { acceptsEnvironments(it) } : false
        }
        return true
    }

    protected boolean acceptsEnvironments(final String... environments) {
        Assert.notEmpty(environments, "Must specify at least one environment")
        for (environment in environments) {
            if (isNegateEnvironment(environment)) {
                if (!isProfileActive(environment[1..-1])) {
                    return true
                }
            } else if (isProfileActive(environment)) {
                return true
            }
        }
        return false
    }

    private boolean isNegateEnvironment(final String environment) {
        environment != null && environment.length() > 0 && environment[0] == '!'
    }

    protected boolean isProfileActive(final String profile) {
        validateEnvironment(profile);
        final String currentEnvironment = Environment.current.name
        profile == currentEnvironment
    }

    protected void validateEnvironment(final String environment) {
        if (!environment || environment.allWhitespace) {
            throw new IllegalArgumentException("Invalid environment [$environment]: must contain text");
        }
        if (environment[0] == '!') {
            throw new IllegalArgumentException("Invalid environment [$environment]: must not begin with ! operator");
        }
    }

}

Next we create a new annotation @GrailsEnv. The annotation will accept a String value or an array of String values with the name(s) of the Grails environments the bean must be registered for or excluded from:

// File: src/java/com/mrhaki/grails/context/annotation/GrailsEnv.java
package com.mrhaki.grails.context.annotation;

import org.springframework.context.annotation.Conditional;

import java.lang.annotation.*;

/**
 * <p>Indicates that a component is eligible for registration when one
 * or more {@linkplain #value specified Grails environments} are active.</p>
 *
 * <p>The Grails environment can be set via the Java system property
 * <em>grails.env</em>.</p>
 *
 * <p>The {@code @GrailsEnv} annotation may be used in any of the following ways:
 * <ul>
 * <li>as a type-level annotation on any class directly or indirectly annotated with
 * {@code @Component},
 * including {@link org.springframework.context.annotation.Configuration @Configuration} classes</li>
 * <li>as a meta-annotation, for the purpose of composing custom stereotype annotations</li>
 * <li>as a method-level annotation on
 * any {@link org.springframework.context.annotation.Bean @Bean} method</li>
 * </ul>
 *
 * <p>If a {@code @Configuration} class is marked with {@code @GrailEnv},
 * all of the {@code @Bean} methods and
 * {@link org.springframework.context.annotation.Import @Import} annotations associated with that class
 * will be bypassed unless one or more of the specified Grails environments are active.</p>
 *
 * <p>If a given Grails environment is prefixed with the NOT operator ({@code !}),
 * the annotated beans or components will be registered if the Grails environment
 * is <em>not</em> active. e.g., for {@code @GrailsEnv("!production")}, registration will occur
 * if Grails environment 'production' is not active.</p>
 *
 * <p>If the {@code @GrailsEnv} annotation is omitted, registration will occur, regardless
 * of which Grails environment is active.
 *
 * @author Hubert A. Klein Ikkink aka mrhaki
 * @see org.springframework.context.annotation.Profile
 * @see com.mrhaki.grails.annotation.context.GrailsEnvCondition
 */
@Retention(RetentionPolicy.RUNTIME)
@Target({ElementType.TYPE, ElementType.METHOD})
@Conditional(GrailsEnvCondition.class)
public @interface GrailsEnv {

    /**
     * Annotation attribute value to set Grails environments.
     * Use an array of String value to determine Grails environments
     * or use a single String value (is automatically put in array).
     * Environment maybe prefixed with {@code !} to register component when environment
     * is NOT active.
     */
    String[] value();

}

We can use our new annotation in a Spring Java configuration class. The following sample shows different values for the @GrailsEnv annotation. The annotation is applied to methods in the sample code, but can also be applied to a class.

// File: src/groovy/com/mrhaki/grails/configuration/BeansConfiguration.groovy
package com.mrhaki.grails.configuration

import com.mrhaki.grails.context.annotation.GrailsEnv
import org.springframework.context.annotation.*

@Configuration
class BeansConfiguration {

    // Load for Grails environments 
    // development or test
    @Bean
    @GrailsEnv(['development', 'test'])
    Sample sampleBean() {
        new Sample('sampleBean')
    }

    // Load for every Grails environment NOT
    // being production.
    @Bean
    @GrailsEnv('!production')
    Sample sample() {
        new Sample('sample')
    }

    // Load for custom environment name qa.
    @Bean
    @GrailsEnv('qa')
    Sample sampleQA() {
        new Sample('QA')
    }

}

We can also use the annotation for classes that are annotated with the @Component annotation:

// File: src/groovy/com/mrhaki/grails/Person.groovy
package 

import com.mrhaki.grails.context.annotation.GrailsEnv
import org.springframework.stereotype.Component

@Component
@GrailsEnv('development')
class Person {
    String name
    String email
}

The implementation for GrailsEnv and GrailsEnvCondition is based on the existing Spring classes Profile and ProfileCondition.

Code written with Grails 2.4.2.

Grail (web browser) Spring Framework Java (programming language) Annotation

Published at DZone with permission of Hubert Klein Ikkink, DZone MVB. See the original article here.

Opinions expressed by DZone contributors are their own.

Trending

  • Micro Frontends on Monorepo With Remote State Management
  • Fun Is the Glue That Makes Everything Stick, Also the OCP
  • Working on an Unfamiliar Codebase
  • Integration Architecture Guiding Principles, A Reference

Comments

Partner Resources

X

ABOUT US

  • About DZone
  • Send feedback
  • Careers
  • Sitemap

ADVERTISE

  • Advertise with DZone

CONTRIBUTE ON DZONE

  • Article Submission Guidelines
  • Become a Contributor
  • Visit the Writers' Zone

LEGAL

  • Terms of Service
  • Privacy Policy

CONTACT US

  • 600 Park Offices Drive
  • Suite 300
  • Durham, NC 27709
  • support@dzone.com

Let's be friends: