| /** |
| * 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 java.util.ArrayList; |
| import java.util.List; |
| |
| import org.apache.hadoop.classification.InterfaceAudience; |
| import org.apache.hadoop.classification.InterfaceStability; |
| import org.apache.hadoop.fs.FileStatus; |
| import org.apache.hadoop.hdfs.protocol.proto.HdfsProtos.BlockProto; |
| |
| /** |
| * Given an external reference, create a sequence of blocks and associated |
| * metadata. |
| */ |
| @InterfaceAudience.Public |
| @InterfaceStability.Unstable |
| public abstract class BlockResolver { |
| |
| protected BlockProto buildBlock(long blockId, long bytes) { |
| return buildBlock(blockId, bytes, 1001); |
| } |
| |
| protected BlockProto buildBlock(long blockId, long bytes, long genstamp) { |
| BlockProto.Builder b = BlockProto.newBuilder() |
| .setBlockId(blockId) |
| .setNumBytes(bytes) |
| .setGenStamp(genstamp); |
| return b.build(); |
| } |
| |
| /** |
| * @param s the external reference. |
| * @return sequence of blocks that make up the reference. |
| */ |
| public Iterable<BlockProto> resolve(FileStatus s) { |
| List<Long> lengths = blockLengths(s); |
| ArrayList<BlockProto> ret = new ArrayList<>(lengths.size()); |
| long tot = 0; |
| for (long l : lengths) { |
| tot += l; |
| ret.add(buildBlock(nextId(), l)); |
| } |
| if (tot != s.getLen()) { |
| // log a warning? |
| throw new IllegalStateException( |
| "Expected " + s.getLen() + " found " + tot); |
| } |
| return ret; |
| } |
| |
| /** |
| * @return the next block id. |
| */ |
| public abstract long nextId(); |
| |
| /** |
| * @return the maximum sequentially allocated block ID for this filesystem. |
| */ |
| protected abstract long lastId(); |
| |
| /** |
| * @param status the external reference. |
| * @return the lengths of the resultant blocks. |
| */ |
| protected abstract List<Long> blockLengths(FileStatus status); |
| |
| |
| /** |
| * @param status the external reference. |
| * @return the block size to assign to this external reference. |
| */ |
| public long preferredBlockSize(FileStatus status) { |
| return status.getBlockSize(); |
| } |
| |
| /** |
| * @param status the external reference. |
| * @return the replication to assign to this external reference. |
| */ |
| public abstract int getReplication(FileStatus status); |
| |
| } |