hadoop SerialNumberManager 源码

  • 2022-10-20
  • 浏览 (30)

haddop SerialNumberManager 代码

文件路径:/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/SerialNumberManager.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.hadoop.hdfs.server.namenode;

import org.apache.hadoop.hdfs.server.namenode.INodeWithAdditionalFields.PermissionStatusFormat;
import org.apache.hadoop.hdfs.util.LongBitFormat;

import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
import java.util.Map.Entry;

/** Manage name-to-serial-number maps for various string tables. */
public enum SerialNumberManager {
  GLOBAL(),
  USER(PermissionStatusFormat.USER, AclEntryStatusFormat.NAME),
  GROUP(PermissionStatusFormat.GROUP, AclEntryStatusFormat.NAME),
  XATTR(XAttrFormat.NAME);

  private static final SerialNumberManager[] values = values();
  private static final int maxEntryBits;
  private static final int maxEntryNumber;
  private static final int maskBits;

  private SerialNumberMap<String> serialMap;
  private int bitLength = Integer.SIZE;

  static {
    maxEntryBits = Integer.numberOfLeadingZeros(values.length);
    maxEntryNumber = (1 << maxEntryBits) - 1;
    maskBits = Integer.SIZE - maxEntryBits;
    for (SerialNumberManager snm : values) {
      // account for string table mask bits.
      snm.updateLength(maxEntryBits);
      snm.serialMap = new SerialNumberMap<String>(snm);
      FSDirectory.LOG.info(snm + " serial map: bits=" + snm.getLength() +
          " maxEntries=" + snm.serialMap.getMax());
    }
  }

  SerialNumberManager(LongBitFormat.Enum... elements) {
    // compute the smallest bit length registered with the serial manager.
    for (LongBitFormat.Enum element : elements) {
      updateLength(element.getLength());
    }
  }

  int getLength() {
    return bitLength;
  }

  private void updateLength(int maxLength) {
    bitLength = Math.min(bitLength, maxLength);
  }

  public int getSerialNumber(String u) {
    return serialMap.get(u);
  }

  public String getString(int id) {
    return serialMap.get(id);
  }

  public String getString(int id, StringTable stringTable) {
    return (stringTable != null)
        ? stringTable.get(this, id) : getString(id);
  }

  private int getMask(int bits) {
    return ordinal() << (Integer.SIZE - bits);
  }

  private static int getMaskBits() {
    return maskBits;
  }

  private int size() {
    return serialMap.size();
  }

  private Iterable<Entry<Integer, String>> entrySet() {
    return serialMap.entrySet();
  }

  // returns snapshot of current values for a save.
  public static StringTable getStringTable() {
    // approximate size for capacity.
    int size = 0;
    for (final SerialNumberManager snm : values) {
      size += snm.size();
    }
    int tableMaskBits = getMaskBits();
    StringTable map = new StringTable(size, tableMaskBits);
    for (final SerialNumberManager snm : values) {
      final int mask = snm.getMask(tableMaskBits);
      for (Entry<Integer, String> entry : snm.entrySet()) {
        map.put(entry.getKey() | mask, entry.getValue());
      }
    }
    return map;
  }

  // returns an empty table for load.
  public static StringTable newStringTable(int size, int bits) {
    if (bits > maskBits) {
      throw new IllegalArgumentException(
        "String table bits " + bits + " > " + maskBits);
    }
    return new StringTable(size, bits);
  }

  public static class StringTable implements Iterable<Entry<Integer, String>> {
    private final int tableMaskBits;
    private final Map<Integer,String> map;

    private StringTable(int size, int loadingMaskBits) {
      this.tableMaskBits = loadingMaskBits;
      this.map = new HashMap<>(size);
    }

    private String get(SerialNumberManager snm, int id) {
      if (tableMaskBits != 0) {
        if (id > maxEntryNumber) {
          throw new IllegalStateException(
              "serial id " + id + " > " + maxEntryNumber);
        }
        id |= snm.getMask(tableMaskBits);
      }
      return map.get(id);
    }

    public void put(int id, String str) {
      map.put(id, str);
    }

    public Iterator<Entry<Integer, String>> iterator() {
      return map.entrySet().iterator();
    }

    public int size() {
      return map.size();
    }

    public int getMaskBits() {
      return tableMaskBits;
    }
  }
}

相关信息

hadoop 源码目录

相关文章

hadoop AclEntryStatusFormat 源码

hadoop AclFeature 源码

hadoop AclStorage 源码

hadoop AclTransformation 源码

hadoop AuditLogger 源码

hadoop BackupImage 源码

hadoop BackupJournalManager 源码

hadoop BackupNode 源码

hadoop BackupState 源码

hadoop CacheManager 源码

0  赞