Add ValueExpression infrastructure for query methods.

Introduce ValueExpressionQueryRewriter as replacement for SpelQueryContext and QueryMethodValueEvaluationContextAccessor to encapsulate common ValueExpression functionality for Spring Data modules wanting to resolve Value Expressions in query methods.

Reduce dependencies in RepositoryFactoryBeanSupport and RepositoryFactorySupport to EvaluationContextProvider instead of QueryMethodEvaluationContextProvider to simplify dependencies.

Deprecate QueryMethodEvaluationContextProvider and its reactive variant for future removal.

Closes #3049
Original pull request: #3050

Author: mp911de

src/main/java/org/springframework/data/expression/CompositeValueExpression.java

@@ -72,4 +72,10 @@ public String evaluate(ValueEvaluationContext context) {
 
 		return builder.toString();
 	}
+
+	@Override
+	public Class<?> getValueType(ValueEvaluationContext context) {
+		return String.class;
+	}
+
 }

src/main/java/org/springframework/data/expression/DefaultValueEvaluationContext.java

@@ -17,14 +17,15 @@
 
 import org.springframework.core.env.Environment;
 import org.springframework.expression.EvaluationContext;
+import org.springframework.lang.Nullable;
 
 /**
  * Default {@link ValueEvaluationContext}.
  *
  * @author Mark Paluch
  * @since 3.3
  */
-record DefaultValueEvaluationContext(Environment environment,
+record DefaultValueEvaluationContext(@Nullable Environment environment,
 		EvaluationContext evaluationContext) implements ValueEvaluationContext {
 
 	@Override

src/main/java/org/springframework/data/expression/DefaultValueExpressionParser.java

@@ -22,6 +22,7 @@
 import org.springframework.expression.Expression;
 import org.springframework.expression.ParseException;
 import org.springframework.expression.ParserContext;
+import org.springframework.expression.spel.standard.SpelExpressionParser;
 import org.springframework.util.Assert;
 import org.springframework.util.SystemPropertyUtils;
 
@@ -39,6 +40,8 @@ class DefaultValueExpressionParser implements ValueExpressionParser {
 	public static final int PLACEHOLDER_PREFIX_LENGTH = PLACEHOLDER_PREFIX.length();
 	public static final char[] QUOTE_CHARS = { '\'', '"' };
 
+	public static final ValueExpressionParser DEFAULT = new DefaultValueExpressionParser(SpelExpressionParser::new);
+
 	private final ValueParserConfiguration configuration;
 
 	public DefaultValueExpressionParser(ValueParserConfiguration configuration) {

src/main/java/org/springframework/data/expression/ExpressionExpression.java

@@ -47,9 +47,14 @@ public boolean isLiteral() {
 	public Object evaluate(ValueEvaluationContext context) {
 
 		EvaluationContext evaluationContext = context.getEvaluationContext();
-		if (evaluationContext != null) {
-			return expression.getValue(evaluationContext);
-		}
-		return expression.getValue();
+		return evaluationContext != null ? expression.getValue(evaluationContext) : expression.getValue();
 	}
+
+	@Override
+	public Class<?> getValueType(ValueEvaluationContext context) {
+
+		EvaluationContext evaluationContext = context.getEvaluationContext();
+		return evaluationContext != null ? expression.getValueType(evaluationContext) : expression.getValueType();
+	}
+
 }

src/main/java/org/springframework/data/expression/LiteralValueExpression.java

@@ -39,4 +39,9 @@ public String evaluate(ValueEvaluationContext context) {
 		return expression;
 	}
 
+	@Override
+	public Class<?> getValueType(ValueEvaluationContext context) {
+		return String.class;
+	}
+
 }

src/main/java/org/springframework/data/expression/PlaceholderExpression.java

@@ -38,7 +38,7 @@ public boolean isLiteral() {
 	}
 
 	@Override
-	public Object evaluate(ValueEvaluationContext context) {
+	public String evaluate(ValueEvaluationContext context) {
 
 		Environment environment = context.getEnvironment();
 		if (environment != null) {
@@ -51,4 +51,9 @@ public Object evaluate(ValueEvaluationContext context) {
 		return expression;
 	}
 
+	@Override
+	public Class<?> getValueType(ValueEvaluationContext context) {
+		return String.class;
+	}
+
 }

src/main/java/org/springframework/data/expression/ReactiveValueEvaluationContextProvider.java

@@ -0,0 +1,54 @@
+/*
+ * Copyright 2024 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.springframework.data.expression;
+
+import reactor.core.publisher.Mono;
+
+import org.springframework.data.spel.ExpressionDependencies;
+import org.springframework.lang.Nullable;
+
+/**
+ * Reactive extension to {@link ValueEvaluationContext} for obtaining a {@link ValueEvaluationContext} that participates
+ * in the reactive flow.
+ *
+ * @author Mark Paluch
+ * @since 3.4
+ */
+public interface ReactiveValueEvaluationContextProvider extends ValueEvaluationContextProvider {
+
+	/**
+	 * Return a {@link ValueEvaluationContext} built using the given parameter values.
+	 *
+	 * @param rootObject the root object to set in the {@link ValueEvaluationContext}.
+	 * @return a mono that emits exactly one {@link ValueEvaluationContext}.
+	 */
+	Mono<ValueEvaluationContext> getEvaluationContextLater(@Nullable Object rootObject);
+
+	/**
+	 * Return a tailored {@link ValueEvaluationContext} built using the given parameter values and considering
+	 * {@link ExpressionDependencies expression dependencies}. The returned {@link ValueEvaluationContext} may contain a
+	 * reduced visibility of methods and properties/fields according to the required {@link ExpressionDependencies
+	 * expression dependencies}.
+	 *
+	 * @param rootObject the root object to set in the {@link ValueEvaluationContext}.
+	 * @param dependencies the requested expression dependencies to be available.
+	 * @return a mono that emits exactly one {@link ValueEvaluationContext}.
+	 */
+	default Mono<ValueEvaluationContext> getEvaluationContextLater(@Nullable Object rootObject,
+			ExpressionDependencies dependencies) {
+		return getEvaluationContextLater(rootObject);
+	}
+}

src/main/java/org/springframework/data/expression/ValueEvaluationContext.java

@@ -36,7 +36,7 @@ public interface ValueEvaluationContext {
 	 * @param evaluationContext
 	 * @return a new {@link ValueEvaluationContext} for the given environment and evaluation context.
 	 */
-	static ValueEvaluationContext of(Environment environment, EvaluationContext evaluationContext) {
+	static ValueEvaluationContext of(@Nullable Environment environment, EvaluationContext evaluationContext) {
 		return new DefaultValueEvaluationContext(environment, evaluationContext);
 	}
 
@@ -51,8 +51,26 @@ static ValueEvaluationContext of(Environment environment, EvaluationContext eval
 	/**
 	 * Returns the {@link EvaluationContext} if provided.
 	 *
-	 * @return the {@link EvaluationContext} or {@literal null}.
+	 * @return the {@link EvaluationContext} or {@literal null} if not set.
 	 */
 	@Nullable
 	EvaluationContext getEvaluationContext();
+
+	/**
+	 * Returns the required {@link EvaluationContext} or throws {@link IllegalStateException} if there is no evaluation
+	 * context available.
+	 *
+	 * @return the {@link EvaluationContext}.
+	 * @since 3.4
+	 */
+	default EvaluationContext getRequiredEvaluationContext() {
+
+		EvaluationContext evaluationContext = getEvaluationContext();
+
+		if (evaluationContext == null) {
+			throw new IllegalStateException("No evaluation context available");
+		}
+
+		return evaluationContext;
+	}
 }

src/main/java/org/springframework/data/expression/ValueEvaluationContextProvider.java

@@ -17,13 +17,15 @@
 
 import org.springframework.data.spel.ExpressionDependencies;
 import org.springframework.expression.EvaluationContext;
+import org.springframework.lang.Nullable;
 
 /**
  * SPI to provide to access a centrally defined potentially shared {@link ValueEvaluationContext}.
  *
  * @author Mark Paluch
  * @since 3.3
  */
+@FunctionalInterface
 public interface ValueEvaluationContextProvider {
 
 	/**
@@ -32,7 +34,7 @@ public interface ValueEvaluationContextProvider {
 	 * @param rootObject the root object to set in the {@link EvaluationContext}.
 	 * @return
 	 */
-	ValueEvaluationContext getEvaluationContext(Object rootObject);
+	ValueEvaluationContext getEvaluationContext(@Nullable Object rootObject);
 
 	/**
 	 * Return a tailored {@link EvaluationContext} built using the given parameter values and considering
@@ -44,7 +46,8 @@ public interface ValueEvaluationContextProvider {
 	 * @param dependencies the requested expression dependencies to be available.
 	 * @return
 	 */
-	default ValueEvaluationContext getEvaluationContext(Object rootObject, ExpressionDependencies dependencies) {
+	default ValueEvaluationContext getEvaluationContext(@Nullable Object rootObject,
+			ExpressionDependencies dependencies) {
 		return getEvaluationContext(rootObject);
 	}
 }

src/main/java/org/springframework/data/expression/ValueExpression.java

@@ -62,4 +62,15 @@ default ExpressionDependencies getExpressionDependencies() {
 	@Nullable
 	Object evaluate(ValueEvaluationContext context) throws EvaluationException;
 
+	/**
+	 * Return the most general type that the expression would use as return type for the given context.
+	 *
+	 * @param context the context in which to evaluate the expression.
+	 * @return the most general type of value.
+	 * @throws EvaluationException if there is a problem determining the type
+	 * @since 3.4
+	 */
+	@Nullable
+	Class<?> getValueType(ValueEvaluationContext context) throws EvaluationException;
+
 }