HSEARCH-1429 Allow advanced implementors of DynamicShardingStrategy t…

…o narrow down shards id set on delete operations

engine/src/main/java/org/hibernate/search/engine/impl/DynamicShardingStrategy.java

@@ -78,7 +78,7 @@ public IndexManager getIndexManagerForAddition(Class<?> entity, Serializable id,
 
 	@Override
 	public IndexManager[] getIndexManagersForDeletion(Class<?> entity, Serializable id, String idInString) {
-		Set<String> shardIdentifiers = shardIdentifierProvider.getAllShardIdentifiers();
+		Set<String> shardIdentifiers = shardIdentifierProvider.getShardIdentifiersForDeletion( entity, id, idInString );
 		return getIndexManagersFromShards( shardIdentifiers );
 	}
 

engine/src/main/java/org/hibernate/search/store/ShardIdentifierProvider.java

@@ -41,6 +41,8 @@
  * Instead of implementing this interface directly, implementations should be derived from
  * {@link ShardIdentifierProviderTemplate} as new methods might be added to this interface in future releases.
  *
+ * @experimental The exact method signatures are likely to change in future.
+ *
  * @author Emmanuel Bernard <emmanuel@hibernate.org>
  * @author Hardy Ferentschik
  * @author Sanne Grinovero <sanne@hibernate.org> (C) 2013 Red Hat Inc.
@@ -65,7 +67,7 @@ public interface ShardIdentifierProvider {
 	 * <br/>
 	 * Concurrency: this method could be invoked concurrently. That means you could have multiple invocations of
 	 * {@link #getShardIdentifier(Class, Serializable, String, Document)}, {@link #getShardIdentifiersForQuery(FullTextFilterImplementor[])},
-	 * {@link #getAllShardIdentifiers()}.
+	 * {@link #getAllShardIdentifiers()}, {@link #getShardIdentifiersForDeletion(Class, Serializable, String)}.
 	 *
 	 * @param entityType the type of the entity
 	 * @param id the id of the entity
@@ -83,7 +85,7 @@ public interface ShardIdentifierProvider {
 	 * <br/>
 	 * Concurrency: this method could be invoked concurrently. That means you could have multiple invocations of
 	 * {@link #getShardIdentifier(Class, Serializable, String, Document)}, {@link #getShardIdentifiersForQuery(FullTextFilterImplementor[])},
-	 * {@link #getAllShardIdentifiers()}.
+	 * {@link #getAllShardIdentifiers()}, {@link #getShardIdentifiersForDeletion(Class, Serializable, String)}.
 	 *
 	 * @param fullTextFilters the filters which are applied to the current query
 	 *
@@ -98,9 +100,28 @@ public interface ShardIdentifierProvider {
 	 * <br/>
 	 * Concurrency: this method could be invoked concurrently. That means you could have multiple invocations of
 	 * {@link #getShardIdentifier(Class, Serializable, String, Document)}, {@link #getShardIdentifiersForQuery(FullTextFilterImplementor[])},
-	 * {@link #getAllShardIdentifiers()}.
+	 * {@link #getAllShardIdentifiers()}, {@link #getShardIdentifiersForDeletion(Class, Serializable, String)}.
 	 *
-	 * @return the list of all currently known shard identifiers.
+	 * @return the set of all currently known shard identifiers.
 	 */
 	Set<String> getAllShardIdentifiers();
+
+	/**
+	 * Determine the shard identifiers of indexes which might contain an entity identified solely by its id.
+	 * This is needed for purge and delete operations, as no more context is available in such cases.
+	 * <br/>
+	 * This method is made available as some strategies might be able to provide a deterministic answer, but in
+	 * most cases you can safely return the same set as returned by {@link #getAllShardIdentifiers()}.
+	 * <br/>
+	 * Concurrency: this method could be invoked concurrently. That means you could have multiple invocations of
+	 * {@link #getShardIdentifier(Class, Serializable, String, Document)}, {@link #getShardIdentifiersForQuery(FullTextFilterImplementor[])},
+	 * {@link #getAllShardIdentifiers()}, {@link #getShardIdentifiersForDeletion(Class, Serializable, String)}.
+	 *
+	 * @param entityType the type of the entity
+	 * @param id the id of the entity
+	 * @param idAsString the entity id transformed as string via the appropriate document id bridge
+	 *
+	 * @return the set of shards which might contain the document, narrowing down from the given parameters.
+	 */
+	Set<String> getShardIdentifiersForDeletion(Class<?> entityType, Serializable id, String idAsString);
 }

engine/src/main/java/org/hibernate/search/store/ShardIdentifierProviderTemplate.java

@@ -20,6 +20,7 @@
  */
 package org.hibernate.search.store;
 
+import java.io.Serializable;
 import java.util.Collections;
 import java.util.HashSet;
 import java.util.Properties;
@@ -32,6 +33,8 @@
  * Recommended parent class to create custom {@link ShardIdentifierProvider} implementations. Sub-classes must provide a
  * no-arg constructor.
  *
+ * @experimental The exact method signatures are likely to change in future.
+ *
  * @author Sanne Grinovero
  */
 public abstract class ShardIdentifierProviderTemplate implements ShardIdentifierProvider {
@@ -72,4 +75,14 @@ public Set<String> getShardIdentifiersForQuery(FullTextFilterImplementor[] fullT
 		return getAllShardIdentifiers();
 	}
 
+	/**
+	 * Extension point for the case in which you are able to narrow down the shard selection
+	 * to a subset of all shards.
+	 * The default implementation returns all known shard identifiers.
+	 */
+	@Override
+	public Set<String> getShardIdentifiersForDeletion(Class<?> entityType, Serializable id, String idAsString) {
+		return getAllShardIdentifiers();
+	}
+
 }

engine/src/test/java/org/hibernate/search/test/configuration/sharding/ShardingConfigurationTest.java

@@ -338,5 +338,10 @@ public Set<String> getShardIdentifiersForQuery(FullTextFilterImplementor[] fullT
 		public Set<String> getAllShardIdentifiers() {
 			return shards;
 		}
+
+		@Override
+		public Set<String> getShardIdentifiersForDeletion(Class<?> entityType, Serializable id, String idAsString) {
+			return shards;
+		}
 	}
 }