DiskChecker.java
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上传日期:2018-01-08
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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.util;
- import java.io.File;
- import java.io.IOException;
- /**
- * Class that provides utility functions for checking disk problem
- */
- public class DiskChecker {
- public static class DiskErrorException extends IOException {
- public DiskErrorException(String msg) {
- super(msg);
- }
- }
-
- public static class DiskOutOfSpaceException extends IOException {
- public DiskOutOfSpaceException(String msg) {
- super(msg);
- }
- }
-
- /**
- * The semantics of mkdirsWithExistsCheck method is different from the mkdirs
- * method provided in the Sun's java.io.File class in the following way:
- * While creating the non-existent parent directories, this method checks for
- * the existence of those directories if the mkdir fails at any point (since
- * that directory might have just been created by some other process).
- * If both mkdir() and the exists() check fails for any seemingly
- * non-existent directory, then we signal an error; Sun's mkdir would signal
- * an error (return false) if a directory it is attempting to create already
- * exists or the mkdir fails.
- * @param dir
- * @return true on success, false on failure
- */
- public static boolean mkdirsWithExistsCheck(File dir) {
- if (dir.mkdir() || dir.exists()) {
- return true;
- }
- File canonDir = null;
- try {
- canonDir = dir.getCanonicalFile();
- } catch (IOException e) {
- return false;
- }
- String parent = canonDir.getParent();
- return (parent != null) &&
- (mkdirsWithExistsCheck(new File(parent)) &&
- (canonDir.mkdir() || canonDir.exists()));
- }
-
- public static void checkDir(File dir) throws DiskErrorException {
- if (!mkdirsWithExistsCheck(dir))
- throw new DiskErrorException("can not create directory: "
- + dir.toString());
-
- if (!dir.isDirectory())
- throw new DiskErrorException("not a directory: "
- + dir.toString());
-
- if (!dir.canRead())
- throw new DiskErrorException("directory is not readable: "
- + dir.toString());
-
- if (!dir.canWrite())
- throw new DiskErrorException("directory is not writable: "
- + dir.toString());
- }
- }