* Fix AbstractExpressionEvaluator

* Add JavaDocs for the `IntegrationEvaluationContextAware`

Author: artembilan

spring-integration-core/src/main/java/org/springframework/integration/expression/IntegrationEvaluationContextAware.java

@@ -19,8 +19,21 @@
 import org.springframework.expression.EvaluationContext;
 
 /**
+ * Interface to be implemented by beans that wish to be aware of their
+ * owning integration {@link EvaluationContext}, which is the result of
+ * {@link org.springframework.integration.config.IntegrationEvaluationContextFactoryBean}
+ * <p>
+ * The {@link #setIntegrationEvaluationContext} is invoked from
+ * the {@link IntegrationEvaluationContextAwareBeanPostProcessor#afterSingletonsInstantiated()},
+ * not during standard {@code postProcessBefore(After)Initialization} to avoid any
+ * {@code BeanFactory} early access during integration {@link EvaluationContext} retrieval.
+ * Therefore, if it is necessary to use {@link EvaluationContext} in the {@code afterPropertiesSet()},
+ * the {@code IntegrationContextUtils.getEvaluationContext(this.beanFactory)} should be used instead
+ * of this interface implementation.
+ *
  * @author Artem Bilan
  * @since 3.0
+ * @see IntegrationEvaluationContextAwareBeanPostProcessor
  */
 public interface IntegrationEvaluationContextAware {
 

spring-integration-core/src/main/java/org/springframework/integration/util/AbstractExpressionEvaluator.java

@@ -56,8 +56,6 @@ public abstract class AbstractExpressionEvaluator implements BeanFactoryAware, I
 
 	private volatile MessageBuilderFactory messageBuilderFactory = new DefaultMessageBuilderFactory();
 
-	private volatile boolean messageBuilderFactorySet;
-
 	/**
 	 * Specify a BeanFactory in order to enable resolution via <code>@beanName</code> in the expression.
 	 */
@@ -83,16 +81,13 @@ public void setConversionService(ConversionService conversionService) {
 	}
 
 	protected MessageBuilderFactory getMessageBuilderFactory() {
-		if (this.messageBuilderFactory == null) {
-			this.messageBuilderFactory = new DefaultMessageBuilderFactory();
-		}
 		return this.messageBuilderFactory;
 	}
 
 	@Override
 	public void afterPropertiesSet() throws Exception {
 		getEvaluationContext();
-		if (this.messageBuilderFactory == null) {
+		if (this.beanFactory != null) {
 			this.messageBuilderFactory = IntegrationUtils.getMessageBuilderFactory(this.beanFactory);
 		}
 	}