DATACMNS-1534 - Cache BeanFactory lookup for EvaluationContextExtension.

We now cache the BeanFactory lookup for EvaluationContextExtension within the ExtensionAwareEvalutationContextProvider to avoid (expensive) repeated context scans when creating the actual EvaluationContext.

Original pull request: #395.

src/main/java/org/springframework/data/repository/query/ExtensionAwareQueryMethodEvaluationContextProvider.java

@@ -30,7 +30,6 @@ import org.aopalliance.intercept.MethodInvocation;
 import org.springframework.beans.factory.ListableBeanFactory;
 import org.springframework.data.spel.ExtensionAwareEvaluationContextProvider;
 import org.springframework.data.spel.spi.EvaluationContextExtension;
-import org.springframework.data.util.Lazy;
 import org.springframework.data.util.Streamable;
 import org.springframework.expression.EvaluationContext;
 import org.springframework.expression.spel.support.StandardEvaluationContext;
@@ -52,7 +51,7 @@ import org.springframework.util.StringUtils;
  */
 public class ExtensionAwareQueryMethodEvaluationContextProvider implements QueryMethodEvaluationContextProvider {
 
-	private final Lazy<org.springframework.data.spel.ExtensionAwareEvaluationContextProvider> delegate;
+	private final ExtensionAwareEvaluationContextProvider delegate;
 
 	/**
 	 * Creates a new {@link ExtensionAwareQueryMethodEvaluationContextProvider}.
@@ -64,7 +63,7 @@ public class ExtensionAwareQueryMethodEvaluationContextProvider implements Query
 
 		Assert.notNull(beanFactory, "ListableBeanFactory must not be null!");
 
-		this.delegate = Lazy.of(() -> new ExtensionAwareEvaluationContextProvider(() -> getExtensionsFrom(beanFactory)));
+		this.delegate = new ExtensionAwareEvaluationContextProvider(beanFactory);
 	}
 
 	/**
@@ -77,7 +76,7 @@ public class ExtensionAwareQueryMethodEvaluationContextProvider implements Query
 
 		Assert.notNull(extensions, "EvaluationContextExtensions must not be null!");
 
-		this.delegate = Lazy.of(new org.springframework.data.spel.ExtensionAwareEvaluationContextProvider(extensions));
+		this.delegate = new org.springframework.data.spel.ExtensionAwareEvaluationContextProvider(extensions);
 	}
 
 	/*
@@ -87,7 +86,7 @@ public class ExtensionAwareQueryMethodEvaluationContextProvider implements Query
 	@Override
 	public <T extends Parameters<?, ?>> EvaluationContext getEvaluationContext(T parameters, Object[] parameterValues) {
 
-		StandardEvaluationContext evaluationContext = delegate.get().getEvaluationContext(parameterValues);
+		StandardEvaluationContext evaluationContext = delegate.getEvaluationContext(parameterValues);
 
 		evaluationContext.setVariables(collectVariables(parameters, parameterValues));
 

src/main/java/org/springframework/data/spel/ExtensionAwareEvaluationContextProvider.java

@@ -25,7 +25,6 @@ import java.util.List;
 import java.util.Map;
 import java.util.Optional;
 import java.util.concurrent.ConcurrentHashMap;
-import java.util.function.Supplier;
 import java.util.stream.Collectors;
 
 import org.springframework.beans.factory.BeanFactory;
@@ -37,6 +36,7 @@ import org.springframework.data.spel.EvaluationContextExtensionInformation.Exten
 import org.springframework.data.spel.EvaluationContextExtensionInformation.RootObjectInformation;
 import org.springframework.data.spel.spi.EvaluationContextExtension;
 import org.springframework.data.spel.spi.Function;
+import org.springframework.data.util.Lazy;
 import org.springframework.data.util.Optionals;
 import org.springframework.expression.AccessException;
 import org.springframework.expression.EvaluationContext;
@@ -66,7 +66,7 @@ public class ExtensionAwareEvaluationContextProvider implements EvaluationContex
 
 	private final Map<Class<?>, EvaluationContextExtensionInformation> extensionInformationCache = new ConcurrentHashMap<>();
 
-	private final Supplier<? extends Collection<? extends EvaluationContextExtension>> extensions;
+	private final Lazy<? extends Collection<? extends EvaluationContextExtension>> extensions;
 	private ListableBeanFactory beanFactory;
 
 	ExtensionAwareEvaluationContextProvider() {
@@ -81,7 +81,7 @@ public class ExtensionAwareEvaluationContextProvider implements EvaluationContex
 	 */
 	public ExtensionAwareEvaluationContextProvider(ListableBeanFactory beanFactory) {
 
-		this(() -> getExtensionsFrom(beanFactory));
+		this(Lazy.of(() -> getExtensionsFrom(beanFactory)));
 
 		this.beanFactory = beanFactory;
 	}
@@ -92,7 +92,7 @@ public class ExtensionAwareEvaluationContextProvider implements EvaluationContex
 	 * @param extensions must not be {@literal null}.
 	 */
 	public ExtensionAwareEvaluationContextProvider(Collection<? extends EvaluationContextExtension> extensions) {
-		this(() -> extensions);
+		this(Lazy.of(extensions));
 	}
 
 	/* (non-Javadoc)

src/test/java/org/springframework/data/repository/query/ExtensionAwareEvaluationContextProviderUnitTests.java

@@ -16,6 +16,9 @@
 package org.springframework.data.repository.query;
 
 import static org.assertj.core.api.Assertions.*;
+import static org.mockito.ArgumentMatchers.anyBoolean;
+import static org.mockito.ArgumentMatchers.eq;
+import static org.mockito.Mockito.*;
 
 import lombok.RequiredArgsConstructor;
 
@@ -31,10 +34,13 @@ import java.util.concurrent.atomic.AtomicInteger;
 
 import org.junit.Before;
 import org.junit.Test;
+import org.mockito.Mockito;
+import org.springframework.beans.factory.ListableBeanFactory;
 import org.springframework.data.domain.PageRequest;
 import org.springframework.data.domain.Pageable;
 import org.springframework.data.domain.Sort;
 import org.springframework.data.domain.Sort.Direction;
+import org.springframework.data.spel.ExtensionAwareEvaluationContextProvider;
 import org.springframework.data.spel.spi.EvaluationContextExtension;
 import org.springframework.data.spel.spi.Function;
 import org.springframework.expression.EvaluationContext;
@@ -279,6 +285,33 @@ public class ExtensionAwareEvaluationContextProviderUnitTests {
 		assertThat(evaluateExpression("methodWithVarArgs('one', 'two')")).isEqualTo("varargs");
 	}
 
+	@Test // DATACMNS-1534
+	public void contextProviderShouldLazilyLookUpExtensions() {
+
+		ListableBeanFactory beanFactory = Mockito.mock(ListableBeanFactory.class);
+
+		ExtensionAwareEvaluationContextProvider contextProvider = new ExtensionAwareEvaluationContextProvider(beanFactory);
+
+		verify(beanFactory, never()).getBeansOfType(eq(EvaluationContextExtension.class), anyBoolean(), anyBoolean());
+
+		contextProvider.getEvaluationContext(null);
+
+		verify(beanFactory).getBeansOfType(eq(EvaluationContextExtension.class), anyBoolean(), anyBoolean());
+	}
+
+	@Test // DATACMNS-1534
+	public void contextProviderShouldLookupExtensionsOnlyOnce() {
+
+		ListableBeanFactory beanFactory = Mockito.mock(ListableBeanFactory.class);
+
+		ExtensionAwareEvaluationContextProvider contextProvider = new ExtensionAwareEvaluationContextProvider(beanFactory);
+
+		contextProvider.getEvaluationContext(null);
+		contextProvider.getEvaluationContext(null);
+
+		verify(beanFactory).getBeansOfType(eq(EvaluationContextExtension.class), anyBoolean(), anyBoolean());
+	}
+
 	private static ExtensionAwareQueryMethodEvaluationContextProvider createContextProviderWithOverloads() {
 
 		return new ExtensionAwareQueryMethodEvaluationContextProvider(Collections.singletonList( //