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Improve handling NULL for optional results. (#131) #132

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Merged
zantvoort merged 1 commit into from
Jun 8, 2026
Merged

Improve handling NULL for optional results. (#131) #132

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35 changes: 26 additions & 9 deletions storm-core/src/main/java/st/orm/core/template/Query.java
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Original file line number Diff line number Diff line change
Expand Up @@ -278,27 +278,44 @@ default <T extends Data> List<Ref<T>> getRefList(@Nonnull Class<T> type, @Nonnul
*/
private <T> T singleResult(@Nonnull Stream<T> stream) {
try (stream) {
return stream
.reduce((a, b) -> {
throw new NonUniqueResultException("Expected single result, but found more than one.");
}).orElseThrow(() -> new NoResultException("Expected single result, but found none."));
var iterator = stream.iterator();
if (!iterator.hasNext()) {
throw new NoResultException("Expected single result, but found none.");
}
T result = iterator.next();
if (iterator.hasNext()) {
throw new NonUniqueResultException("Expected single result, but found more than one.");
}
if (result == null) {
throw new PersistenceException("Expected single result, but found null. Wrap the field in COALESCE() to provide a non-null default.");
}
return result;
}
}

/**
* Returns the single result of the stream, or an empty optional if there is no result.
*
* @param stream the stream to get the single result from.
* @return the single result of the stream.
* @param <T> the type of the result.
* @return the single result of the stream.
* @throws NonUniqueResultException if more than one result.
* @throws PersistenceException if the single row's value is null.
*/
private <T> Optional<T> optionalResult(@Nonnull Stream<T> stream) {
try (stream) {
return stream
.reduce((a, b) -> {
throw new NonUniqueResultException("Expected single result, but found more than one.");
});
var iterator = stream.iterator();
if (!iterator.hasNext()) {
return Optional.empty();
}
T result = iterator.next();
if (iterator.hasNext()) {
throw new NonUniqueResultException("Expected single result, but found more than one.");
}
if (result == null) {
throw new PersistenceException("Result is null. Wrap the field in COALESCE() to provide a non-null default.");
}
return Optional.of(result);
}
}
}
35 changes: 26 additions & 9 deletions storm-core/src/main/java/st/orm/core/template/QueryBuilder.java
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Expand Up @@ -946,29 +946,46 @@ public final List<R> getResultList() {
* @return the single result.
* @throws NoResultException if there is no result.
* @throws NonUniqueResultException if more than one result.
* @throws PersistenceException if the query fails.
* @throws PersistenceException if the single row's value is null, or the query fails.
*/
public final R getSingleResult() {
try (var stream = getResultStream()) {
return stream
.reduce((a, b) -> {
throw new NonUniqueResultException("Expected single result, but found more than one.");
}).orElseThrow(() -> new NoResultException("Expected single result, but found none."));
var iterator = stream.iterator();
if (!iterator.hasNext()) {
throw new NoResultException("Expected single result, but found none.");
}
R result = iterator.next();
if (iterator.hasNext()) {
throw new NonUniqueResultException("Expected single result, but found more than one.");
}
if (result == null) {
throw new PersistenceException("Expected single result, but found null. Wrap the field in COALESCE() to provide a non-null default.");
}
return result;
}
}

/**
* Executes the query and returns an optional result.
*
* @return the optional result.
* @return the optional result; {@link Optional#empty()} when no row matched.
* @throws NonUniqueResultException if more than one result.
* @throws PersistenceException if the query fails.
* @throws PersistenceException if the single row's value is null, or the query fails.
*/
public final Optional<R> getOptionalResult() {
try (var stream = getResultStream()) {
return stream.reduce((a, b) -> {
var iterator = stream.iterator();
if (!iterator.hasNext()) {
return Optional.empty();
}
R result = iterator.next();
if (iterator.hasNext()) {
throw new NonUniqueResultException("Expected single result, but found more than one.");
});
}
if (result == null) {
throw new PersistenceException("Result is null. Wrap the field in COALESCE() to provide a non-null default.");
}
return Optional.of(result);
}
}

Expand Down
46 changes: 33 additions & 13 deletions storm-kotlin/src/main/kotlin/st/orm/template/Query.kt
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Original file line number Diff line number Diff line change
Expand Up @@ -20,8 +20,8 @@ import kotlinx.coroutines.stream.consumeAsFlow
import st.orm.Data
import st.orm.NoResultException
import st.orm.NonUniqueResultException
import st.orm.PersistenceException
import st.orm.Ref
import java.util.function.Supplier
import java.util.stream.Stream
import kotlin.reflect.KClass

Expand Down Expand Up @@ -318,29 +318,49 @@ interface Query {
*/
private fun <T> singleResult(stream: Stream<T>): T {
stream.use {
return stream
.reduce { _, _ ->
throw NonUniqueResultException("Expected single result, but found more than one.")
}
.orElseThrow(Supplier { NoResultException("Expected single result, but found none.") })
val iterator = stream.iterator()
if (!iterator.hasNext()) {
throw NoResultException("Expected single result, but found none.")
}
val result = iterator.next()
if (iterator.hasNext()) {
throw NonUniqueResultException("Expected single result, but found more than one.")
}
if (result == null) {
throw PersistenceException("Expected single result, but found null. Wrap the field in COALESCE() to provide a non-null default.")
}
return result
}
}

/**
* Returns the single result of the stream, or an empty optional if there is no result.
* Returns the single result of the stream, or `null` if there is no result.
*
* Iterates the stream explicitly rather than using [Stream.reduce] — the standard reduce internally
* calls `Optional.of(element)`, which throws a message-less [NullPointerException] when the only
* element is `null`. The iterator form lets the method detect that case and report it via a typed
* [PersistenceException] with a clear message.
*
* @param stream the stream to get the single result from.
* @return the single result of the stream.
* @param <T> the type of the result.
* @return the single result of the stream, or `null` when no row matched.
* @throws NonUniqueResultException if more than one result.
* @throws PersistenceException if the single row's value is SQL NULL.
*/
private fun <T> optionalResult(stream: Stream<T>): T? {
stream.use {
return stream
.reduce { _, _ ->
throw NonUniqueResultException("Expected single result, but found more than one.")
}
.orElse(null)
val iterator = stream.iterator()
if (!iterator.hasNext()) {
return null
}
val result = iterator.next()
if (iterator.hasNext()) {
throw NonUniqueResultException("Expected single result, but found more than one.")
}
if (result == null) {
throw PersistenceException("Result is null. Wrap the field in COALESCE() to provide a non-null default.")
}
return result
}
}
}
36 changes: 25 additions & 11 deletions storm-kotlin/src/main/kotlin/st/orm/template/QueryBuilder.kt
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Original file line number Diff line number Diff line change
Expand Up @@ -25,7 +25,6 @@ import st.orm.template.TemplateString.Companion.raw
import st.orm.template.TemplateString.Companion.wrap
import st.orm.template.impl.create
import st.orm.template.impl.createRef
import java.util.function.Supplier
import java.util.stream.Stream
import kotlin.reflect.KClass

Expand Down Expand Up @@ -1015,32 +1014,47 @@ interface QueryBuilder<T : Data, R, ID> {
* @return the single result.
* @throws NoResultException if there is no result.
* @throws NonUniqueResultException if more than one result.
* @throws PersistenceException if the query fails.
* @throws PersistenceException if the single row's value is null, or the query fails.
*/
get() {
resultStream.use { stream ->
return stream
.reduce { _, _ ->
throw NonUniqueResultException("Expected single result, but found more than one.")
}
.orElseThrow(Supplier { NoResultException("Expected single result, but found none.") })
val iterator = stream.iterator()
if (!iterator.hasNext()) {
throw NoResultException("Expected single result, but found none.")
}
val result = iterator.next()
if (iterator.hasNext()) {
throw NonUniqueResultException("Expected single result, but found more than one.")
}
if (result == null) {
throw PersistenceException("Expected single result, but found null. Wrap the field in COALESCE() to provide a non-null default.")
}
return result
}
}

val optionalResult: R?
/**
* Executes the query and returns an optional result.
*
* @return the optional result.
* @return the optional result; `null` when no row matched.
* @throws NonUniqueResultException if more than one result.
* @throws PersistenceException if the query fails.
* @throws PersistenceException if the single row's value is null, or the query fails.
*/
get() {
resultStream.use { stream ->
return stream.reduce { _, _ ->
val iterator = stream.iterator()
if (!iterator.hasNext()) {
return null
}
val result = iterator.next()
if (iterator.hasNext()) {
throw NonUniqueResultException("Expected single result, but found more than one.")
}
.orElse(null)
if (result == null) {
throw PersistenceException("Result is null. Wrap the field in COALESCE() to provide a non-null default.")
}
return result
}
}

Expand Down
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