package org.infinispan.stream.impl.termop;
import java.util.ArrayList;
import java.util.Collection;
import java.util.List;
import java.util.Map;
import java.util.function.Supplier;
import java.util.stream.BaseStream;
import java.util.stream.Stream;
import org.infinispan.commons.util.ByRef;
import org.infinispan.container.entries.CacheEntry;
import org.infinispan.container.entries.ImmortalCacheEntry;
import org.infinispan.stream.impl.KeyTrackingTerminalOperation;
import org.infinispan.stream.impl.intops.IntermediateOperation;
/**
* This is a base operation class for the use of the for each terminal operator. This class can be used for any
* forEach configuration, however since it relies on generics it may not be as performant as a primitive based
* for each operation.
* This class assumes the stream is composed of {@link java.util.Map.Entry} instances where the key is typed the same
* as defined K type.
* @param <K> key type of underlying stream
* @param <V> value type of transformed stream
* @param <S> type of the transformed stream
*/
public abstract class AbstractForEachOperation<K, V, S extends BaseStream<V, S>> extends BaseTerminalOperation
implements KeyTrackingTerminalOperation<K, V, K> {
private final int batchSize;
public AbstractForEachOperation(Iterable<IntermediateOperation> intermediateOperations,
Supplier<Stream<CacheEntry>> supplier, int batchSize) {
super(intermediateOperations, supplier);
this.batchSize = batchSize;
}
@Override
public boolean lostSegment(boolean stopIfLost) {
// TODO: stop this early
return true;
}
@Override
public List<V> performOperation(IntermediateCollector<Collection<V>> response) {
/**
* This is for rehash only! {@link SingleRunOperation} should always be used for non rehash for each
*/
throw new UnsupportedOperationException();
}
protected abstract void handleList(List<V> list);
protected abstract void handleStreamForEach(S stream, List<V> list);
@Override
public Collection<CacheEntry<K, K>> performOperationRehashAware(
IntermediateCollector<Collection<CacheEntry<K, K>>> response) {
// We only support sequential streams for forEach rehash aware
BaseStream<?, ?> stream = supplier.get().sequential();
List<CacheEntry<K, K>> collectedValues = new ArrayList<>(batchSize);
List<V> currentList = new ArrayList<>();
ByRef<K> currentKey = new ByRef<>(null);
stream = ((Stream<Map.Entry<K, ?>>) stream).peek(e -> {
if (!currentList.isEmpty()) {
collectedValues.add(new ImmortalCacheEntry(currentKey.get(), null));
if (collectedValues.size() >= batchSize) {
handleList(currentList);
response.sendDataResonse(collectedValues);
collectedValues.clear();
currentList.clear();
}
}
currentKey.set(e.getKey());
});
for (IntermediateOperation intermediateOperation : intermediateOperations) {
stream = intermediateOperation.perform(stream);
}
S convertedStream = ((S) stream);
// We rely on the fact that forEach processes 1 entry at a time
handleStreamForEach(convertedStream, currentList);
if (!currentList.isEmpty()) {
handleList(currentList);
collectedValues.add(new ImmortalCacheEntry(currentKey.get(), null));
}
return collectedValues;
}
public int getBatchSize() {
return batchSize;
}
}