[hibernate-issues] [Hibernate-JIRA] Resolved: (HSHARDS-9) Add ShardAware interface and related exit strategy logic

Add ShardAware interface and related exit strategy logic -------------------------------------------------------- Key: HSHARDS-9 URL: http://opensource.atlassian.com/projects/hibernate/browse/HSHARDS-9 Project: Hibernate Shards Issue Type: New Feature Components: strategy Affects Versions: 3.0.0.Beta1 Environment: Hibernate 3.2, Database: DB2 Reporter: Nathan Silberman Assignee: Max Ross Fix For: 3.0.0 Original Estimate: 2 days Remaining Estimate: 2 days Domain model awareness of its host Shard. Any domain model that implemented a 'ShardAware' interface would contain a Set<ShardId> that could be injected by the relevant ExitStrategy. This could be solved by adding the following interface: ------------------------------------------------------- package org.hibernate.shards; import org.hibernate.shards.ShardId; import java.util.Set; /** * Interface for persistent objects that are aware of the virtual shardIds * that host them. */ public interface ShardAware { /** * Sets the virtual ShardIds that host the implementing * persistant object * * @param shardid * a non-null, non-empty Set of ShardIds * @throws IllegalArgumentException * if <tt>shardIds</tt> is null or empty */ void setShardIds( Set<ShardId> shardids ); } --------------------------------------------------- An simple exit strategy that could be used, for example, would set the ShardIds for each resulting ShardAware domain model: ------------------------------------------------------ package org.hibernate.shards.strategy.exit; import java.util.List; import org.hibernate.shards.Shard; import org.hibernate.shards.ShardAware; /** * ShardAwareConcatenateListsExistStrategy sets the ShardIds on each of the given * objects returned by each Shard. * * One should be aware that usage of this class adds O(n) overhead to each retrieval * as the setting of each ShardIds Set is invoked by iterating over the entire resultSet. */ public class ShardAwareConcatenateListsExistStrategy extends ConcatenateListsExitStrategy { @Override public synchronized boolean addResult(List<Object> oneResult, Shard shard ) { if ( oneResult != null && ! oneResult.isEmpty() && oneResult.get( 0 ) instanceof ShardAware ) { for( Object object : oneResult ) { ((ShardAware)object).setShardIds( shard.getShardIds() ); } } return super.addResult( oneResult, shard ); } } --------------------------------------- This change might require changes wherever ShardAccessStrategy.apply() could be invoked. I have made the changes including a small alteration to the ShardedCriteriaImpl, to use ShardAwareConcatenateListsExistStrategy instead of ConcatenateListsExitStrategy, with success.