spark RocksDBIterator 源码

2022-10-20
浏览 (385)

spark RocksDBIterator 代码

文件路径：/common/network-common/src/main/java/org/apache/spark/network/shuffledb/RocksDBIterator.java

/*
 * 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.spark.network.shuffledb;

import java.io.IOException;
import java.util.AbstractMap;
import java.util.Map;
import java.util.NoSuchElementException;

import com.google.common.base.Throwables;
import org.rocksdb.RocksIterator;

/**
 * RocksDB implementation of `DBIterator`.
 */
public class RocksDBIterator implements DBIterator {

    private final RocksIterator it;

    private boolean checkedNext;

    private boolean closed;

    private Map.Entry<byte[], byte[]> next;

    public RocksDBIterator(RocksIterator it) {
      this.it = it;
    }

    @Override
    public boolean hasNext() {
      if (!checkedNext && !closed) {
        next = loadNext();
        checkedNext = true;
      }
      if (!closed && next == null) {
        try {
          close();
        } catch (IOException ioe) {
          throw Throwables.propagate(ioe);
        }
      }
      return next != null;
    }

    @Override
    public Map.Entry<byte[], byte[]> next() {
      if (!hasNext()) {
        throw new NoSuchElementException();
      }
      checkedNext = false;
      Map.Entry<byte[], byte[]> ret = next;
      next = null;
      return ret;
    }

    @Override
    public void close() throws IOException {
      if (!closed) {
        it.close();
        closed = true;
        next = null;
      }
    }

    @Override
    public void seek(byte[] key) {
      it.seek(key);
    }

    private Map.Entry<byte[], byte[]> loadNext() {
      if (it.isValid()) {
        Map.Entry<byte[], byte[]> nextEntry =
          new AbstractMap.SimpleEntry<>(it.key(), it.value());
        it.next();
        return nextEntry;
      }
      return null;
    }
}

相关信息

spark 源码目录

相关文章

spark DB 源码

spark DBBackend 源码

spark DBIterator 源码

spark LevelDB 源码

spark LevelDBIterator 源码

spark RocksDB 源码

spark StoreVersion 源码

0 赞

所属分类： 前端技术
本文标签： 大数据
版权声明： 原创文章如转载，请注明本文链接: https://www.seaxiang.com/blog/e6553de8bec747778102a2c5ca9b4be4

热门推荐

1、直接访问google.com
2、 - 优质文章
3、 gate.io
4、 harmony 鸿蒙hdc使用指导
5、 harmony 鸿蒙初识ArkTS语言
6、 harmony 鸿蒙ArkUI组件（ArkTS）开发常见问题
7、 flink kafka connector scan.startup.mode 的几个选项
8、 golang
9、 openharmony
10、 Vue中input框自动聚焦

Loading...