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HHH-17212 Avoid jdbc isBeforeFirst() and isAfterLast() calls

This commit is contained in:
Marco Belladelli 2023-09-07 12:24:42 +02:00 committed by Steve Ebersole
parent 6103eb896f
commit 1ec4f75575
1 changed files with 34 additions and 29 deletions
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63
hibernate-core/src/main/java/org/hibernate/internal/FetchingScrollableResultsImpl.java
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@ -31,6 +31,8 @@ public class FetchingScrollableResultsImpl<R> extends AbstractScrollableResults<
private int currentPosition;
private Integer maxPosition;
private boolean beforeFirst;
private boolean afterLast;
public FetchingScrollableResultsImpl(
JdbcValues jdbcValues,
@ -51,6 +53,7 @@ public class FetchingScrollableResultsImpl<R> extends AbstractScrollableResults<
resultInitializer = extractResultInitializer( rowReader );
this.maxPosition = jdbcValuesSourceProcessingState.getQueryOptions().getEffectiveLimit().getMaxRows();
beforeFirst = true;
}
private static <R> EntityInitializer extractResultInitializer(RowReader<R> rowReader) {
@ -65,23 +68,30 @@ public class FetchingScrollableResultsImpl<R> extends AbstractScrollableResults<
@Override
public boolean next() {
if ( maxPosition != null && maxPosition <= currentPosition ) {
currentRow = null;
if ( afterLast || isResultSetEmpty() ) {
return false;
}
else if ( maxPosition != null && maxPosition <= currentPosition ) {
currentPosition = maxPosition + 1;
return false;
}
if ( isResultSetEmpty() ) {
currentRow = null;
currentPosition = 0;
afterLast = true;
beforeFirst = false;
return false;
}
else if ( beforeFirst ) {
if ( !getRowProcessingState().next() ) {
currentPosition = 0;
beforeFirst = false;
return false;
}
}
boolean afterLast = prepareCurrentRow();
boolean last = prepareCurrentRow();
beforeFirst = false;
currentPosition++;
if ( afterLast ) {
if ( last ) {
if ( maxPosition == null ) {
// we just hit the last position
maxPosition = currentPosition;
@ -96,15 +106,12 @@ public class FetchingScrollableResultsImpl<R> extends AbstractScrollableResults<
@Override
public boolean previous() {
if ( currentPosition <= 1 ) {
currentPosition = 0;
currentRow = null;
if ( beforeFirst || isResultSetEmpty() ) {
return false;
}
if ( getRowProcessingState().isFirst() ) {
// don't even bother trying to read any further
currentRow = null;
else if ( currentPosition == 1 ) {
beforeFirst();
return false;
}
else {
EntityKey keyToRead = null;
@ -117,7 +124,7 @@ public class FetchingScrollableResultsImpl<R> extends AbstractScrollableResults<
// In the latter scenario, the previous logical row
// really is the last logical row.
//
if ( getRowProcessingState().isAfterLast() && maxPosition != null && currentPosition > maxPosition ) {
if ( afterLast ) {
// position cursor to the last row
getRowProcessingState().last();
keyToRead = getEntityKey();
@ -167,6 +174,7 @@ public class FetchingScrollableResultsImpl<R> extends AbstractScrollableResults<
prepareCurrentRow();
}
afterLast = false;
currentPosition--;
afterScrollOperation();
@ -229,13 +237,13 @@ public class FetchingScrollableResultsImpl<R> extends AbstractScrollableResults<
}
else {
final RowProcessingStateStandardImpl rowProcessingState = getRowProcessingState();
if ( isResultSetEmpty() || rowProcessingState.isAfterLast() ) {
if ( isResultSetEmpty() || afterLast ) {
// should not be able to reach last without maxPosition being set
// unless there are no results
return false;
}
while ( !rowProcessingState.isAfterLast() ) {
while ( !afterLast ) {
more = next();
}
}
@ -258,6 +266,8 @@ public class FetchingScrollableResultsImpl<R> extends AbstractScrollableResults<
@Override
public void beforeFirst() {
getRowProcessingState().beforeFirst();
beforeFirst = true;
afterLast = false;
currentRow = null;
currentPosition = 0;
}
@ -302,13 +312,9 @@ public class FetchingScrollableResultsImpl<R> extends AbstractScrollableResults<
private boolean prepareCurrentRow() {
final RowProcessingStateStandardImpl rowProcessingState = getRowProcessingState();
if ( rowProcessingState.isBeforeFirst() ) {
rowProcessingState.next();
}
final RowReader<R> rowReader = getRowReader();
boolean afterLast = false;
boolean last = false;
boolean resultProcessed = false;
final EntityKey entityKey = getEntityKey();
@ -328,7 +334,7 @@ public class FetchingScrollableResultsImpl<R> extends AbstractScrollableResults<
if ( !entityKey.equals( entityKey2 ) ) {
resultInitializer.finishUpRow( rowProcessingState );
resultProcessed = true;
afterLast = false;
last = false;
}
else {
rowReader.readRow( rowProcessingState, getProcessingOptions() );
@ -336,7 +342,7 @@ public class FetchingScrollableResultsImpl<R> extends AbstractScrollableResults<
}
}
else {
afterLast = true;
last = true;
resultProcessed = true;
}
@ -349,12 +355,12 @@ public class FetchingScrollableResultsImpl<R> extends AbstractScrollableResults<
}
persistenceContext.initializeNonLazyCollections();
afterScrollOperation();
return afterLast;
return last;
}
private boolean isResultSetEmpty() {
return currentPosition == 0 && !getRowProcessingState().isBeforeFirst() && !getRowProcessingState().isAfterLast();
return currentPosition == 0 && !beforeFirst && !afterLast;
}
private EntityKey getEntityKey() {
@ -363,5 +369,4 @@ public class FetchingScrollableResultsImpl<R> extends AbstractScrollableResults<
resultInitializer.finishUpRow( getRowProcessingState() );
return entityKey;
}
}