| /** |
| * 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.datanode; |
| |
| import java.util.HashMap; |
| import java.util.Map; |
| import java.util.SortedSet; |
| |
| import org.apache.hadoop.classification.InterfaceAudience; |
| import org.apache.hadoop.hdfs.protocol.LayoutVersion; |
| import org.apache.hadoop.hdfs.protocol.LayoutVersion.FeatureInfo; |
| import org.apache.hadoop.hdfs.protocol.LayoutVersion.LayoutFeature; |
| |
| @InterfaceAudience.Private |
| public class DataNodeLayoutVersion { |
| /** Build layout version and corresponding feature matrix */ |
| public final static Map<Integer, SortedSet<LayoutFeature>> FEATURES = |
| new HashMap<Integer, SortedSet<LayoutFeature>>(); |
| |
| public static final int CURRENT_LAYOUT_VERSION |
| = LayoutVersion.getCurrentLayoutVersion(Feature.values()); |
| |
| static{ |
| LayoutVersion.updateMap(FEATURES, LayoutVersion.Feature.values()); |
| LayoutVersion.updateMap(FEATURES, DataNodeLayoutVersion.Feature.values()); |
| } |
| |
| public static SortedSet<LayoutFeature> getFeatures(int lv) { |
| return FEATURES.get(lv); |
| } |
| |
| public static boolean supports(final LayoutFeature f, final int lv) { |
| return LayoutVersion.supports(FEATURES, f, lv); |
| } |
| |
| /** |
| * Enums for features that change the layout version. |
| * <br><br> |
| * To add a new layout version: |
| * <ul> |
| * <li>Define a new enum constant with a short enum name, the new layout version |
| * and description of the added feature.</li> |
| * <li>When adding a layout version with an ancestor that is not same as |
| * its immediate predecessor, use the constructor where a specific ancestor |
| * can be passed. |
| * </li> |
| * </ul> |
| */ |
| public static enum Feature implements LayoutFeature { |
| FIRST_LAYOUT(-55, -53, "First datanode layout", false), |
| BLOCKID_BASED_LAYOUT(-56, |
| "The block ID of a finalized block uniquely determines its position " + |
| "in the directory structure"), |
| BLOCKID_BASED_LAYOUT_32_by_32(-57, |
| "Identical to the block id based layout (-56) except it uses a smaller" |
| + " directory structure (32x32)"); |
| |
| private final FeatureInfo info; |
| |
| /** |
| * DataNodeFeature that is added at layout version {@code lv} - 1. |
| * @param lv new layout version with the addition of this feature |
| * @param description description of the feature |
| */ |
| Feature(final int lv, final String description) { |
| this(lv, lv + 1, description, false); |
| } |
| |
| /** |
| * DataNode feature that is added at layout version {@code ancestoryLV}. |
| * @param lv new layout version with the addition of this feature |
| * @param ancestorLV layout version from which the new lv is derived from. |
| * @param description description of the feature |
| * @param reserved true when this is a layout version reserved for previous |
| * version |
| * @param features set of features that are to be enabled for this version |
| */ |
| Feature(final int lv, final int ancestorLV, final String description, |
| boolean reserved, Feature... features) { |
| info = new FeatureInfo(lv, ancestorLV, description, reserved, features); |
| } |
| |
| @Override |
| public FeatureInfo getInfo() { |
| return info; |
| } |
| } |
| } |