org.apache.kafka.streams.state.internals.RocksDbIterator Maven / Gradle / Ivy
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* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.kafka.streams.state.internals;
import org.apache.kafka.common.utils.AbstractIterator;
import org.apache.kafka.common.utils.Bytes;
import org.apache.kafka.streams.KeyValue;
import org.apache.kafka.streams.errors.InvalidStateStoreException;
import org.rocksdb.RocksIterator;
import java.util.NoSuchElementException;
import java.util.function.Consumer;
class RocksDbIterator extends AbstractIterator> implements ManagedKeyValueIterator {
private final String storeName;
private final RocksIterator iter;
private final Consumer advanceIterator;
private volatile boolean open = true;
private KeyValue next;
private Runnable closeCallback = null;
RocksDbIterator(final String storeName,
final RocksIterator iter,
final boolean forward) {
this.storeName = storeName;
this.iter = iter;
this.advanceIterator = forward ? RocksIterator::next : RocksIterator::prev;
}
@Override
public synchronized boolean hasNext() {
if (!open) {
throw new InvalidStateStoreException(String.format("RocksDB iterator for store %s has closed", storeName));
}
return super.hasNext();
}
@Override
protected KeyValue makeNext() {
if (!iter.isValid()) {
return allDone();
} else {
next = getKeyValue();
advanceIterator.accept(iter);
return next;
}
}
private KeyValue getKeyValue() {
return new KeyValue<>(new Bytes(iter.key()), iter.value());
}
@Override
public synchronized void close() {
if (closeCallback == null) {
throw new IllegalStateException("RocksDbIterator expects close callback to be set immediately upon creation");
}
closeCallback.run();
iter.close();
open = false;
}
@Override
public Bytes peekNextKey() {
if (!hasNext()) {
throw new NoSuchElementException();
}
return next.key;
}
@Override
public synchronized void onClose(final Runnable closeCallback) {
this.closeCallback = closeCallback;
}
}