CavalliumDBEngine/src/main/java/it/cavallium/dbengine/database/collections/SubStageGetterSingle.java

57 lines
1.5 KiB
Java

package it.cavallium.dbengine.database.collections;
import it.cavallium.dbengine.client.CompositeSnapshot;
import it.cavallium.dbengine.database.LLDictionary;
import it.cavallium.dbengine.database.serialization.Serializer;
import java.util.Arrays;
import org.jetbrains.annotations.Nullable;
import reactor.core.publisher.Flux;
import reactor.core.publisher.Mono;
public class SubStageGetterSingle<T> implements SubStageGetter<T, DatabaseStageEntry<T>> {
private static final boolean assertsEnabled;
static {
boolean assertsEnabledTmp = false;
//noinspection AssertWithSideEffects
assert assertsEnabledTmp = true;
//noinspection ConstantConditions
assertsEnabled = assertsEnabledTmp;
}
private final Serializer<T, byte[]> serializer;
public SubStageGetterSingle(Serializer<T, byte[]> serializer) {
this.serializer = serializer;
}
@Override
public Mono<DatabaseStageEntry<T>> subStage(LLDictionary dictionary,
@Nullable CompositeSnapshot snapshot,
byte[] keyPrefix,
Flux<byte[]> debuggingKeyFlux) {
return debuggingKeyFlux
.singleOrEmpty()
.flatMap(key -> Mono
.<DatabaseStageEntry<T>>fromCallable(() -> {
if (!Arrays.equals(keyPrefix, key)) {
throw new IndexOutOfBoundsException("Found more than one element!");
}
return null;
})
)
.then(Mono.fromSupplier(() -> new DatabaseSingle<>(dictionary, keyPrefix, serializer)));
}
@Override
public boolean isMultiKey() {
return false;
}
@Override
public boolean needsDebuggingKeyFlux() {
return assertsEnabled;
}
}