org.apache.kafka.streams.state.internals.RocksDBRangeIterator Maven / Gradle / Ivy
/*
* 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.Bytes;
import org.apache.kafka.streams.KeyValue;
import org.rocksdb.RocksIterator;
import java.util.Comparator;
class RocksDBRangeIterator extends RocksDbIterator {
// RocksDB's JNI interface does not expose getters/setters that allow the
// comparator to be pluggable, and the default is lexicographic, so it's
// safe to just force lexicographic comparator here for now.
private final Comparator comparator = Bytes.BYTES_LEXICO_COMPARATOR;
private final byte[] rawLastKey;
private final boolean forward;
private final boolean toInclusive;
RocksDBRangeIterator(final String storeName,
final RocksIterator iter,
final Bytes from,
final Bytes to,
final boolean forward,
final boolean toInclusive) {
super(storeName, iter, forward);
this.forward = forward;
this.toInclusive = toInclusive;
if (forward) {
if (from == null) {
iter.seekToFirst();
} else {
iter.seek(from.get());
}
rawLastKey = to == null ? null : to.get();
} else {
if (to == null) {
iter.seekToLast();
} else {
iter.seekForPrev(to.get());
}
rawLastKey = from == null ? null : from.get();
}
}
@Override
protected KeyValue makeNext() {
final KeyValue next = super.makeNext();
if (next == null) {
return allDone();
} else if (rawLastKey == null) {
//null means range endpoint is open
return next;
} else {
if (forward) {
if (comparator.compare(next.key.get(), rawLastKey) < 0) {
return next;
} else if (comparator.compare(next.key.get(), rawLastKey) == 0) {
return toInclusive ? next : allDone();
} else {
return allDone();
}
} else {
if (comparator.compare(next.key.get(), rawLastKey) >= 0) {
return next;
} else {
return allDone();
}
}
}
}
}