HHH-13496 Identified some String appending in loops

hibernate-core/src/main/java/org/hibernate/dialect/Teradata14Dialect.java

@@ -254,7 +254,8 @@ public class Teradata14Dialect extends TeradataDialect {
 			final StringBuilder buf = new StringBuilder()
 					.append( "create index " )
 					.append( indexNameForCreation )
-					.append(  "(" + colBuf  )
+					.append(  '(' )
+					.append( colBuf )
 					.append( " on " )
 					.append( tableName );
 

hibernate-core/src/main/java/org/hibernate/hql/internal/ast/tree/MapEntryNode.java

@@ -92,16 +92,20 @@ public class MapEntryNode extends AbstractMapComponentNode implements Aggregated
 		determineKeySelectExpressions( collectionPersister, selections );
 		determineValueSelectExpressions( collectionPersister, selections );
 
-		String text = "";
+		final int columnNumber = selections.size();
-		String[] columns = new String[selections.size()];
+		StringBuilder text = new StringBuilder( columnNumber * 12 ); //Some guess
-		for ( int i = 0; i < selections.size(); i++ ) {
+		String[] columns = new String[columnNumber];
+		for ( int i = 0; i < columnNumber; i++ ) {
 			SelectExpression selectExpression = (SelectExpression) selections.get( i );
-			text += ( ", " + selectExpression.getExpression() + " as " + selectExpression.getAlias() );
+			if ( i != 0 ) {
+				text.append( ", " );
+			}
+			text.append( selectExpression.getExpression() );
+			text.append( " as " );
+			text.append( selectExpression.getAlias() );
 			columns[i] = selectExpression.getExpression();
 		}
-
+		setText( text.toString() );
-		text = text.substring( 2 ); //strip leading ", "
-		setText( text );
 		setResolved();
 		return columns;
 	}

hibernate-core/src/main/java/org/hibernate/internal/util/StringHelper.java

@@ -318,14 +318,15 @@ public final class StringHelper {
 	 */
 	public static String collapseQualifier(String qualifier, boolean includeDots) {
 		StringTokenizer tokenizer = new StringTokenizer( qualifier, "." );
-		String collapsed = Character.toString( tokenizer.nextToken().charAt( 0 ) );
+		StringBuilder sb = new StringBuilder();
+		sb.append( Character.toString( tokenizer.nextToken().charAt( 0 ) ) );
 		while ( tokenizer.hasMoreTokens() ) {
 			if ( includeDots ) {
-				collapsed += '.';
+				sb.append( '.' );
 			}
-			collapsed += tokenizer.nextToken().charAt( 0 );
+			sb.append( tokenizer.nextToken().charAt( 0 ) );
 		}
-		return collapsed;
+		return sb.toString();
 	}
 
 	/**

hibernate-core/src/main/java/org/hibernate/loader/collection/BasicCollectionJoinWalker.java

@@ -8,8 +8,10 @@ package org.hibernate.loader.collection;
 import java.util.ArrayList;
 import java.util.Iterator;
 import java.util.List;
+import java.util.Map;
 
 import org.hibernate.FetchMode;
+import org.hibernate.Filter;
 import org.hibernate.LockMode;
 import org.hibernate.MappingException;
 import org.hibernate.engine.spi.CascadeStyle;
@@ -75,8 +77,9 @@ public class BasicCollectionJoinWalker extends CollectionJoinWalker {
 				batchSize
 			);
 
-		String manyToManyOrderBy = "";
+		StringBuilder sb = null;
-		String filter = collectionPersister.filterFragment( alias, getLoadQueryInfluencers().getEnabledFilters() );
+		final Map<String, Filter> enabledFilters = getLoadQueryInfluencers().getEnabledFilters();
+		String filter = collectionPersister.filterFragment( alias, enabledFilters );
 		if ( collectionPersister.isManyToMany() ) {
 			// from the collection of associations, locate OJA for the
 			// ManyToOne corresponding to this persister to fully
@@ -84,16 +87,17 @@ public class BasicCollectionJoinWalker extends CollectionJoinWalker {
 			// use its alias here
 			// TODO : is there a better way here?
 			Iterator itr = associations.iterator();
+			sb = new StringBuilder( 20 );
 			AssociationType associationType = ( AssociationType ) collectionPersister.getElementType();
 			while ( itr.hasNext() ) {
 				OuterJoinableAssociation oja = ( OuterJoinableAssociation ) itr.next();
 				if ( oja.getJoinableType() == associationType ) {
 					// we found it
 					filter += collectionPersister.getManyToManyFilterFragment( 
-							oja.getRHSAlias(), 
+							oja.getRHSAlias(),
-							getLoadQueryInfluencers().getEnabledFilters() 
+							enabledFilters
 						);
-					manyToManyOrderBy += collectionPersister.getManyToManyOrderByString( oja.getRHSAlias() );
+					sb.append( collectionPersister.getManyToManyOrderByString( oja.getRHSAlias() ) );
 				}
 			}
 		}
@@ -103,7 +107,7 @@ public class BasicCollectionJoinWalker extends CollectionJoinWalker {
 		Select select = new Select( getDialect() )
 			.setSelectClause(
 				collectionPersister.selectFragment(alias, collectionSuffixes[0] ) +
-				selectString(associations)
+				selectString( associations )
 			)
 			.setFromClause( collectionPersister.getTableName(), alias )
 			.setWhereClause( whereString.toString()	)
@@ -112,7 +116,7 @@ public class BasicCollectionJoinWalker extends CollectionJoinWalker {
 				ojf.toWhereFragmentString()
 			);
 
-		select.setOrderByClause( orderBy( associations, mergeOrderings( collectionPersister.getSQLOrderByString(alias), manyToManyOrderBy ) ) );
+		select.setOrderByClause( orderBy( associations, mergeOrderings( collectionPersister.getSQLOrderByString( alias ), sb == null ? "" : sb.toString() ) ) );
 
 		if ( getFactory().getSettings().isCommentsEnabled() ) {
 			select.setComment( "load collection " + collectionPersister.getRole() );