DATAMONGO-2112 - Allow SpEL expression to be used for annotated index & geoIndex names as well as compound index definition.

We now also evaluate SpEL expressions for the name of indices as well as the def attribute of the compound index definition.

   @CompoundIndex(name = "#{'cmp' + 2 + 'name‘}“, def = "#{T(org.bson.Document).parse(\"{ 'foo': 1, 'bar': -1 }\")}")
    class WithCompoundIndexFromExpression {
      // …
    }

An expression used for Indexed.expireAfter may now not only return a plain String value with the timeout but also a java.time.Duration.

Original pull request: #647.

Author: christophstrobl

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/index/CompoundIndex.java

@@ -36,10 +36,29 @@
 public @interface CompoundIndex {
 
 	/**
-	 * The actual index definition in JSON format. The keys of the JSON document are the fields to be indexed, the values
-	 * define the index direction (1 for ascending, -1 for descending). <br />
+	 * The actual index definition in JSON format or a {@link org.springframework.expression.spel.standard.SpelExpression
+	 * template expression} resolving to either a JSON String or a {@link org.bson.Document}. The keys of the JSON
+	 * document are the fields to be indexed, the values define the index direction (1 for ascending, -1 for descending).
+	 * <br />
 	 * If left empty on nested document, the whole document will be indexed.
 	 *
+	 * <pre>
+	 * <code>
+	 *
+	 * &#64;Document
+	 * &#64;CompoundIndex(def = "{'h1': 1, 'h2': 1}")
+	 * class JsonStringIndexDefinition {
+	 *   String h1, h2;
+	 * }
+	 *
+	 * &#64;Document
+	 * &#64;CompoundIndex(def = "#{T(org.bson.Document).parse("{ 'h1': 1, 'h2': 1 }")}")
+	 * class ExpressionIndexDefinition {
+	 *   String h1, h2;
+	 * }
+	 * </code>
+	 * </pre>
+	 *
 	 * @return
 	 */
 	String def() default "";
@@ -79,7 +98,8 @@
 	boolean dropDups() default false;
 
 	/**
-	 * The name of the index to be created. <br />
+	 * Index name of the index to be created either as plain value or as
+	 * {@link org.springframework.expression.spel.standard.SpelExpression template expression}. <br />
 	 * <br />
 	 * The name will only be applied as is when defined on root level. For usage on nested or embedded structures the
 	 * provided name will be prefixed with the path leading to the entity. <br />

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/index/GeoSpatialIndexed.java

@@ -34,8 +34,8 @@
 public @interface GeoSpatialIndexed {
 
 	/**
-	 * Index name. <br />
-	 * <br />
+	 * Index name either as plain value or as {@link org.springframework.expression.spel.standard.SpelExpression template
+	 * expression}. <br />
 	 * The name will only be applied as is when defined on root level. For usage on nested or embedded structures the
 	 * provided name will be prefixed with the path leading to the entity. <br />
 	 * <br />
@@ -52,6 +52,7 @@
 	 * &#64;Document
 	 * class Hybrid {
 	 *   &#64;GeoSpatialIndexed(name="index") Point h1;
+	 *   &#64;GeoSpatialIndexed(name="#{&#64;myBean.indexName}") Point h2;
 	 * }
 	 *
 	 * class Nested {
@@ -67,6 +68,7 @@
 	 * db.root.createIndex( { hybrid.h1: "2d" } , { name: "hybrid.index" } )
 	 * db.root.createIndex( { nested.n1: "2d" } , { name: "nested.index" } )
 	 * db.hybrid.createIndex( { h1: "2d" } , { name: "index" } )
+	 * db.hybrid.createIndex( { h2: "2d"} , { name: the value myBean.getIndexName() returned } )
 	 * </code>
 	 * </pre>
 	 *

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/index/Indexed.java

@@ -65,7 +65,8 @@
 	boolean dropDups() default false;
 
 	/**
-	 * Index name. <br />
+	 * Index name either as plain value or as {@link org.springframework.expression.spel.standard.SpelExpression template
+	 * expression}. <br />
 	 * <br />
 	 * The name will only be applied as is when defined on root level. For usage on nested or embedded structures the
 	 * provided name will be prefixed with the path leading to the entity. <br />
@@ -83,6 +84,7 @@
 	 * &#64;Document
 	 * class Hybrid {
 	 *   &#64;Indexed(name="index") String h1;
+	 *   &#64;Indexed(name="#{&#64;myBean.indexName}") String h2;
 	 * }
 	 *
 	 * class Nested {
@@ -98,6 +100,7 @@
 	 * db.root.createIndex( { hybrid.h1: 1 } , { name: "hybrid.index" } )
 	 * db.root.createIndex( { nested.n1: 1 } , { name: "nested.index" } )
 	 * db.hybrid.createIndex( { h1: 1} , { name: "index" } )
+	 * db.hybrid.createIndex( { h2: 1} , { name: the value myBean.getIndexName() returned } )
 	 * </code>
 	 * </pre>
 	 *
@@ -135,7 +138,8 @@
 	/**
 	 * Alternative for {@link #expireAfterSeconds()} to configure the timeout after which the collection should expire.
 	 * Defaults to an empty String for no expiry. Accepts numeric values followed by their unit of measure (d(ays),
-	 * h(ours), m(inutes), s(seconds)) or a Spring {@literal template expression}.
+	 * h(ours), m(inutes), s(seconds)) or a Spring {@literal template expression}. The expression can result in a a valid
+	 * expiration {@link String} following the conventions already mentioned or a {@link java.time.Duration}.
 	 *
 	 * <pre>
 	 *     <code>

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/index/MongoPersistentEntityIndexResolver.java

@@ -40,6 +40,7 @@
 import org.springframework.data.mapping.Association;
 import org.springframework.data.mapping.AssociationHandler;
 import org.springframework.data.mapping.MappingException;
+import org.springframework.data.mapping.PersistentEntity;
 import org.springframework.data.mapping.PersistentProperty;
 import org.springframework.data.mapping.PropertyHandler;
 import org.springframework.data.mongodb.core.index.MongoPersistentEntityIndexResolver.CycleGuard.Path;
@@ -62,6 +63,7 @@
 import org.springframework.util.Assert;
 import org.springframework.util.ClassUtils;
 import org.springframework.util.NumberUtils;
+import org.springframework.util.ObjectUtils;
 import org.springframework.util.StringUtils;
 
 /**
@@ -356,10 +358,10 @@ protected IndexDefinitionHolder createCompoundIndexDefinition(String dotPath, St
 			MongoPersistentEntity<?> entity) {
 
 		CompoundIndexDefinition indexDefinition = new CompoundIndexDefinition(
-				resolveCompoundIndexKeyFromStringDefinition(dotPath, index.def()));
+				resolveCompoundIndexKeyFromStringDefinition(dotPath, index.def(), entity));
 
 		if (!index.useGeneratedName()) {
-			indexDefinition.named(pathAwareIndexName(index.name(), dotPath, null));
+			indexDefinition.named(pathAwareIndexName(index.name(), dotPath, entity, null));
 		}
 
 		if (index.unique()) {
@@ -377,7 +379,8 @@ protected IndexDefinitionHolder createCompoundIndexDefinition(String dotPath, St
 		return new IndexDefinitionHolder(dotPath, indexDefinition, collection);
 	}
 
-	private org.bson.Document resolveCompoundIndexKeyFromStringDefinition(String dotPath, String keyDefinitionString) {
+	private org.bson.Document resolveCompoundIndexKeyFromStringDefinition(String dotPath, String keyDefinitionString,
+			PersistentEntity<?, ?> entity) {
 
 		if (!StringUtils.hasText(dotPath) && !StringUtils.hasText(keyDefinitionString)) {
 			throw new InvalidDataAccessApiUsageException("Cannot create index on root level for empty keys.");
@@ -387,7 +390,12 @@ private org.bson.Document resolveCompoundIndexKeyFromStringDefinition(String dot
 			return new org.bson.Document(dotPath, 1);
 		}
 
-		org.bson.Document dbo = org.bson.Document.parse(keyDefinitionString);
+		Object keyDefToUse = evaluatePotentialTemplateExpression(keyDefinitionString,
+				getEvaluationContextForProperty(entity));
+
+		org.bson.Document dbo = (keyDefToUse instanceof org.bson.Document) ? (org.bson.Document) keyDefToUse
+				: org.bson.Document.parse(ObjectUtils.nullSafeToString(keyDefToUse));
+
 		if (!StringUtils.hasText(dotPath)) {
 			return dbo;
 		}
@@ -423,7 +431,7 @@ protected IndexDefinitionHolder createIndexDefinition(String dotPath, String col
 				IndexDirection.ASCENDING.equals(index.direction()) ? Sort.Direction.ASC : Sort.Direction.DESC);
 
 		if (!index.useGeneratedName()) {
-			indexDefinition.named(pathAwareIndexName(index.name(), dotPath, persitentProperty));
+			indexDefinition.named(pathAwareIndexName(index.name(), dotPath, persitentProperty.getOwner(), persitentProperty));
 		}
 
 		if (index.unique()) {
@@ -446,21 +454,12 @@ protected IndexDefinitionHolder createIndexDefinition(String dotPath, String col
 
 			if (index.expireAfterSeconds() >= 0) {
 				throw new IllegalStateException(String.format(
-						"@Indexed already defines an expiration timeout of %s sec. via Indexed#expireAfterSeconds. Please make to use either expireAfterSeconds or expireAfter.", index.expireAfterSeconds()));
-			}
-
-			EvaluationContext ctx = getEvaluationContext();
-
-			if (persitentProperty.getOwner() instanceof BasicMongoPersistentEntity) {
-
-				EvaluationContext contextFromEntity = ((BasicMongoPersistentEntity<?>) persitentProperty.getOwner())
-						.getEvaluationContext(null);
-				if (contextFromEntity != null && !EvaluationContextProvider.DEFAULT.equals(contextFromEntity)) {
-					ctx = contextFromEntity;
-				}
+						"@Indexed already defines an expiration timeout of %s sec. via Indexed#expireAfterSeconds. Please make to use either expireAfterSeconds or expireAfter.",
+						index.expireAfterSeconds()));
 			}
 
-			Duration timeout = computeIndexTimeout(index.expireAfter(), ctx);
+			Duration timeout = computeIndexTimeout(index.expireAfter(),
+					getEvaluationContextForProperty(persitentProperty.getOwner()));
 			if (!timeout.isZero() && !timeout.isNegative()) {
 				indexDefinition.expire(timeout);
 			}
@@ -479,6 +478,27 @@ protected EvaluationContext getEvaluationContext() {
 		return evaluationContextProvider.getEvaluationContext(null);
 	}
 
+	/**
+	 * Get the {@link EvaluationContext} for a given {@link PersistentEntity entity} the default one.
+	 * 
+	 * @param persistentEntity can be {@literal null}
+	 * @return
+	 */
+	private EvaluationContext getEvaluationContextForProperty(@Nullable PersistentEntity<?, ?> persistentEntity) {
+
+		if (persistentEntity == null || !(persistentEntity instanceof BasicMongoPersistentEntity)) {
+			return getEvaluationContext();
+		}
+
+		EvaluationContext contextFromEntity = ((BasicMongoPersistentEntity<?>) persistentEntity).getEvaluationContext(null);
+
+		if (contextFromEntity != null && !EvaluationContextProvider.DEFAULT.equals(contextFromEntity)) {
+			return contextFromEntity;
+		}
+
+		return getEvaluationContext();
+	}
+
 	/**
 	 * Set the {@link EvaluationContextProvider} used for obtaining the {@link EvaluationContext} used to compute
 	 * {@link org.springframework.expression.spel.standard.SpelExpression expressions}.
@@ -514,17 +534,22 @@ protected IndexDefinitionHolder createGeoSpatialIndexDefinition(String dotPath,
 		indexDefinition.withMin(index.min()).withMax(index.max());
 
 		if (!index.useGeneratedName()) {
-			indexDefinition.named(pathAwareIndexName(index.name(), dotPath, persistentProperty));
+			indexDefinition
+					.named(pathAwareIndexName(index.name(), dotPath, persistentProperty.getOwner(), persistentProperty));
 		}
 
 		indexDefinition.typed(index.type()).withBucketSize(index.bucketSize()).withAdditionalField(index.additionalField());
 
 		return new IndexDefinitionHolder(dotPath, indexDefinition, collection);
 	}
 
-	private String pathAwareIndexName(String indexName, String dotPath, @Nullable MongoPersistentProperty property) {
+	private String pathAwareIndexName(String indexName, String dotPath, @Nullable PersistentEntity<?, ?> entity,
+			@Nullable MongoPersistentProperty property) {
 
-		String nameToUse = StringUtils.hasText(indexName) ? indexName : "";
+		String nameToUse = StringUtils.hasText(indexName)
+				? ObjectUtils
+						.nullSafeToString(evaluatePotentialTemplateExpression(indexName, getEvaluationContextForProperty(entity)))
+				: "";
 
 		if (!StringUtils.hasText(dotPath) || (property != null && dotPath.equals(property.getFieldName()))) {
 			return StringUtils.hasText(nameToUse) ? nameToUse : dotPath;
@@ -582,7 +607,17 @@ private void resolveAndAddIndexesForAssociation(Association<MongoPersistentPrope
 	 */
 	private static Duration computeIndexTimeout(String timeoutValue, EvaluationContext evaluationContext) {
 
-		String val = evaluatePotentialTemplateExpression(timeoutValue, evaluationContext);
+		Object evaluatedTimeout = evaluatePotentialTemplateExpression(timeoutValue, evaluationContext);
+
+		if (evaluatedTimeout == null) {
+			return Duration.ZERO;
+		}
+
+		if (evaluatedTimeout instanceof Duration) {
+			return (Duration) evaluatedTimeout;
+		}
+
+		String val = evaluatedTimeout.toString();
 
 		if (val == null) {
 			return Duration.ZERO;
@@ -611,15 +646,14 @@ private static Duration computeIndexTimeout(String timeoutValue, EvaluationConte
 	}
 
 	@Nullable
-	private static String evaluatePotentialTemplateExpression(String value, EvaluationContext evaluationContext) {
+	private static Object evaluatePotentialTemplateExpression(String value, EvaluationContext evaluationContext) {
 
 		Expression expression = PARSER.parseExpression(value, ParserContext.TEMPLATE_EXPRESSION);
 		if (expression instanceof LiteralExpression) {
 			return value;
 		}
 
-		return expression.getValue(evaluationContext, String.class);
-
+		return expression.getValue(evaluationContext, Object.class);
 	}
 
 	/**