/* * 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 io.kcache.utils.rocksdb; import io.kcache.KeyValue; import io.kcache.KeyValueIterator; import io.kcache.exceptions.CacheException; import org.apache.kafka.common.utils.AbstractIterator; import org.rocksdb.RocksIterator; import java.util.Set; class RocksDBIterator extends AbstractIterator<KeyValue<byte[], byte[]>> implements KeyValueIterator<byte[], byte[]> { private final String storeName; private final RocksIterator iter; private final Set<KeyValueIterator<byte[], byte[]>> openIterators; private final boolean isDescending; private volatile boolean open = true; private KeyValue<byte[], byte[]> next; RocksDBIterator(final String storeName, final RocksIterator iter, final Set<KeyValueIterator<byte[], byte[]>> openIterators, final boolean isDescending) { this.storeName = storeName; this.iter = iter; this.openIterators = openIterators; this.isDescending = isDescending; if (isDescending) { iter.seekToLast(); } else { iter.seekToFirst(); } } @Override public synchronized boolean hasNext() { if (!open) { throw new CacheException(String.format("RocksDB iterator for store %s has closed", storeName)); } return super.hasNext(); } @Override public KeyValue<byte[], byte[]> makeNext() { if (!iter.isValid()) { return allDone(); } else { next = getKeyValue(); if (isDescending) { iter.prev(); } else { iter.next(); } return next; } } private KeyValue<byte[], byte[]> getKeyValue() { return new KeyValue<>(iter.key(), iter.value()); } @Override public void remove() { throw new UnsupportedOperationException("RocksDB iterator does not support remove()"); } @Override public synchronized void close() { openIterators.remove(this); iter.close(); open = false; } }