net.sf.jstuff.integration.spring.SpringBeanLocator Maven / Gradle / Ivy

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/*
 * Copyright 2010-2022 by Sebastian Thomschke and contributors.
 * SPDX-License-Identifier: EPL-2.0
 */
package net.sf.jstuff.integration.spring;

import java.util.Map;

import javax.annotation.PreDestroy;

import org.eclipse.jdt.annotation.Nullable;
import org.springframework.beans.factory.ListableBeanFactory;
import org.springframework.beans.factory.NoSuchBeanDefinitionException;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;

import net.sf.jstuff.core.logging.Logger;
import net.sf.jstuff.core.validation.Args;
import net.sf.jstuff.core.validation.Assert;

/**
 *  * <context:annotation-config />
 *
 * <bean class="net.sf.jstuff.integration.spring.SpringBeanLocator" />
 * 
 *
 * or
 *
 *  * <context:annotation-config />
 *
 * <context:component-scan base-package="net.sf.jstuff.integration.spring" />
 * 
 *
 * @author Sebastian Thomschke
 */
@Component
public final class SpringBeanLocator {
   private static final Logger LOG = Logger.create();

   private static @Nullable SpringBeanLocator instance;

   /**
    * @return the default instance (the last instantiated one by any spring context)
    */
   public static SpringBeanLocator get() {
      return Assert.notNull(instance, "Spring context not initialized yet.");
   }

   @Autowired
   private ListableBeanFactory factory;

   private SpringBeanLocator() {
      Assert.isNull(instance, "A instance of " + getClass().getName() + " already exists.");

      LOG.infoNew(this);

      instance = this;
   }

   /**
    * Returns the spring managed bean with the given type
    *
    * @param beanType the type of the bean
    *
    * @return the spring managed bean with the given name
    */
   @SuppressWarnings("unchecked")
   public  T byClass(final Class beanType) {
      Args.notNull("beanType", beanType);

      final Map beans = factory.getBeansOfType(beanType, true, true);
      if (beans.isEmpty())
         throw new IllegalArgumentException("No Spring managed bean for type '" + beanType.getName() //
            + "' was found.");

      if (beans.size() > 1)
         throw new IllegalStateException("More than one Spring managed bean for type '" + beanType.getName() //
            + "' was found.");

      return (T) beans.values().iterator().next();
   }

   /**
    * Returns the spring managed bean with the given name.
    *
    * @param beanName the bean name
    *
    * @return the spring managed bean with the given name
    */
   @SuppressWarnings("unchecked")
   public  T byName(final String beanName) {
      Assert.notNull(beanName, "[beanName] must not be null.");
      try {
         return (T) factory.getBean(beanName);
      } catch (final NoSuchBeanDefinitionException e) {
         throw new IllegalArgumentException("No Spring managed bean for name '" + beanName + "' was found.");
      }
   }

   public ListableBeanFactory getBeanFactory() {
      return factory;
   }

   @PreDestroy
   private void onDestroy() {
      instance = null;
   }
}