HSEARCH-540 Avoid performing the queue twice when nothing has changed

The double registration leads to double processing of the queue which can be avoided by a flag.

git-svn-id: https://svn.jboss.org/repos/hibernate/search/branches/Branch_3_2@19976 1b8cb986-b30d-0410-93ca-fae66ebed9b2

hibernate-search/src/main/java/org/hibernate/search/backend/WorkQueue.java

@@ -42,8 +42,10 @@ public class WorkQueue {
 	private List<Work> queue;
 
 	private List<LuceneWork> sealedQueue;
-	//is this class supposed to be
+	//flag indicating if the sealed data has be provided meaning that it should no longer be modified
 	private boolean usedSealedData;
+	//flag indicating if data has been sealed and not modified since
+	private boolean sealedAndUnchanged;
 
 	public WorkQueue(int size) {
 		queue = new ArrayList<Work>(size);
@@ -53,6 +55,10 @@ private WorkQueue(List<Work> queue) {
 		this.queue = queue;
 	}
 
+	public boolean isSealedAndUnchanged() {
+		return sealedAndUnchanged;
+	}
+
 	public WorkQueue() {
 		this(10);
 	}
@@ -62,6 +68,7 @@ public void add(Work work) {
 			//something is wrong fail with exception
 			throw new AssertionFailure( "Attempting to add a work in a used sealed queue" );
 		}
+		this.sealedAndUnchanged = false;
 		queue.add(work);
 	}
 
@@ -72,12 +79,13 @@ public List<Work> getQueue() {
 	public WorkQueue splitQueue() {
 		WorkQueue subQueue = new WorkQueue( queue );
 		this.queue = new ArrayList<Work>( queue.size() );
+		this.sealedAndUnchanged = false;
 		return subQueue;
 	}
 
 	public List<LuceneWork> getSealedQueue() {
 		if (sealedQueue == null) throw new AssertionFailure("Access a Sealed WorkQueue which has not been sealed");
-		usedSealedData = true;
+		this.sealedAndUnchanged = false;
 		return sealedQueue;
 	}
 
@@ -93,11 +101,13 @@ public void setSealedQueue(List<LuceneWork> sealedQueue) {
 		 * when the flush ordering is fixed, add the following line
 		 * queue = Collections.EMPTY_LIST;
 		 */
+		this.sealedAndUnchanged = true;
 		this.sealedQueue = sealedQueue;
 	}
 
 	public void clear() {
 		queue.clear();
+		this.sealedAndUnchanged = false;
 		if (sealedQueue != null) sealedQueue.clear();
 	}
 

hibernate-search/src/main/java/org/hibernate/search/backend/impl/BatchedQueueingProcessor.java

@@ -134,19 +134,22 @@ public void add(Work work, WorkQueue workQueue) {
 	}
 
 	public void prepareWorks(WorkQueue workQueue) {
-		List<Work> queue = workQueue.getQueue();
-		int initialSize = queue.size();
-		List<LuceneWork> luceneQueue = new ArrayList<LuceneWork>( initialSize ); //TODO load factor for containedIn
-		/**
-		 * Collection work type are process second, so if the owner entity has already been processed for whatever reason
-		 * the work will be ignored.
-		 * However if the owner entity has not been processed, an "UPDATE" work is executed
-		 *
-		 * Processing collection works last is mandatory to avoid reindexing a object to be deleted
-		 */
-		processWorkByLayer( queue, initialSize, luceneQueue, Layer.FIRST );
-		processWorkByLayer( queue, initialSize, luceneQueue, Layer.SECOND );
-		workQueue.setSealedQueue( optimize( luceneQueue ) );
+		final boolean alreadyProcessedAndUnchanged = workQueue.isSealedAndUnchanged();
+		if ( !alreadyProcessedAndUnchanged ) { 
+			List<Work> queue = workQueue.getQueue();
+			int initialSize = queue.size();
+			List<LuceneWork> luceneQueue = new ArrayList<LuceneWork>( initialSize ); //TODO load factor for containedIn
+			/**
+			 * Collection work type are process second, so if the owner entity has already been processed for whatever reason
+			 * the work will be ignored.
+			 * However if the owner entity has not been processed, an "UPDATE" work is executed
+			 *
+			 * Processing collection works last is mandatory to avoid reindexing a object to be deleted
+			 */
+			processWorkByLayer( queue, initialSize, luceneQueue, Layer.FIRST );
+			processWorkByLayer( queue, initialSize, luceneQueue, Layer.SECOND );
+			workQueue.setSealedQueue( optimize( luceneQueue ) );
+		}
 	}
 
 	private List<LuceneWork> optimize(List<LuceneWork> luceneQueue) {