INode.java
上传用户:quxuerui
上传日期:2018-01-08
资源大小:41811k
文件大小:3k
- /**
- * 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.fs.s3;
- import java.io.ByteArrayInputStream;
- import java.io.ByteArrayOutputStream;
- import java.io.DataInputStream;
- import java.io.DataOutputStream;
- import java.io.IOException;
- import java.io.InputStream;
- /**
- * Holds file metadata including type (regular file, or directory),
- * and the list of blocks that are pointers to the data.
- */
- public class INode {
-
- enum FileType {
- DIRECTORY, FILE
- }
-
- public static final FileType[] FILE_TYPES = {
- FileType.DIRECTORY,
- FileType.FILE
- };
- public static final INode DIRECTORY_INODE = new INode(FileType.DIRECTORY, null);
-
- private FileType fileType;
- private Block[] blocks;
- public INode(FileType fileType, Block[] blocks) {
- this.fileType = fileType;
- if (isDirectory() && blocks != null) {
- throw new IllegalArgumentException("A directory cannot contain blocks.");
- }
- this.blocks = blocks;
- }
- public Block[] getBlocks() {
- return blocks;
- }
-
- public FileType getFileType() {
- return fileType;
- }
- public boolean isDirectory() {
- return fileType == FileType.DIRECTORY;
- }
- public boolean isFile() {
- return fileType == FileType.FILE;
- }
-
- public long getSerializedLength() {
- return 1L + (blocks == null ? 0 : 4 + blocks.length * 16);
- }
-
- public InputStream serialize() throws IOException {
- ByteArrayOutputStream bytes = new ByteArrayOutputStream();
- DataOutputStream out = new DataOutputStream(bytes);
- out.writeByte(fileType.ordinal());
- if (isFile()) {
- out.writeInt(blocks.length);
- for (int i = 0; i < blocks.length; i++) {
- out.writeLong(blocks[i].getId());
- out.writeLong(blocks[i].getLength());
- }
- }
- out.close();
- return new ByteArrayInputStream(bytes.toByteArray());
- }
-
- public static INode deserialize(InputStream in) throws IOException {
- if (in == null) {
- return null;
- }
- DataInputStream dataIn = new DataInputStream(in);
- FileType fileType = INode.FILE_TYPES[dataIn.readByte()];
- switch (fileType) {
- case DIRECTORY:
- in.close();
- return INode.DIRECTORY_INODE;
- case FILE:
- int numBlocks = dataIn.readInt();
- Block[] blocks = new Block[numBlocks];
- for (int i = 0; i < numBlocks; i++) {
- long id = dataIn.readLong();
- long length = dataIn.readLong();
- blocks[i] = new Block(id, length);
- }
- in.close();
- return new INode(fileType, blocks);
- default:
- throw new IllegalArgumentException("Cannot deserialize inode.");
- }
- }
-
- }