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Apache Commons VFS is a Virtual File System library.
/*
* 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.commons.vfs2.provider.hdfs;
import java.io.FileNotFoundException;
import java.io.InputStream;
import java.util.HashMap;
import java.util.Map;
import org.apache.commons.vfs2.FileNotFolderException;
import org.apache.commons.vfs2.FileObject;
import org.apache.commons.vfs2.FileSystemException;
import org.apache.commons.vfs2.FileType;
import org.apache.commons.vfs2.RandomAccessContent;
import org.apache.commons.vfs2.provider.AbstractFileName;
import org.apache.commons.vfs2.provider.AbstractFileObject;
import org.apache.commons.vfs2.util.RandomAccessMode;
import org.apache.hadoop.fs.FileStatus;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;
/**
* A VFS representation of an HDFS file.
*
* @since 2.1
*/
public class HdfsFileObject extends AbstractFileObject {
private final HdfsFileSystem fs;
private final FileSystem hdfs;
private final Path path;
private FileStatus stat;
/**
* Constructs a new HDFS FileObject
*
* @param name FileName
* @param fs HdfsFileSystem instance
* @param hdfs Hadoop FileSystem instance
* @param p Path to the file in HDFS
*/
protected HdfsFileObject(final AbstractFileName name, final HdfsFileSystem fs, final FileSystem hdfs,
final Path p) {
super(name, fs);
this.fs = fs;
this.hdfs = hdfs;
this.path = p;
}
/**
* @see org.apache.commons.vfs2.provider.AbstractFileObject#canRenameTo(org.apache.commons.vfs2.FileObject)
*/
@Override
public boolean canRenameTo(final FileObject newfile) {
throw new UnsupportedOperationException();
}
/**
* @see org.apache.commons.vfs2.provider.AbstractFileObject#doAttach()
*/
@Override
protected void doAttach() throws Exception {
try {
this.stat = this.hdfs.getFileStatus(this.path);
} catch (final FileNotFoundException e) {
this.stat = null;
return;
}
}
/**
* @see org.apache.commons.vfs2.provider.AbstractFileObject#doGetAttributes()
*/
@Override
protected Map doGetAttributes() throws Exception {
if (null == this.stat) {
return super.doGetAttributes();
}
final Map attrs = new HashMap<>();
attrs.put(HdfsFileAttributes.LAST_ACCESS_TIME.toString(), this.stat.getAccessTime());
attrs.put(HdfsFileAttributes.BLOCK_SIZE.toString(), this.stat.getBlockSize());
attrs.put(HdfsFileAttributes.GROUP.toString(), this.stat.getGroup());
attrs.put(HdfsFileAttributes.OWNER.toString(), this.stat.getOwner());
attrs.put(HdfsFileAttributes.PERMISSIONS.toString(), this.stat.getPermission().toString());
attrs.put(HdfsFileAttributes.LENGTH.toString(), this.stat.getLen());
attrs.put(HdfsFileAttributes.MODIFICATION_TIME.toString(), this.stat.getModificationTime());
return attrs;
}
/**
* @see org.apache.commons.vfs2.provider.AbstractFileObject#doGetContentSize()
*/
@Override
protected long doGetContentSize() throws Exception {
return stat.getLen();
}
/**
* @see org.apache.commons.vfs2.provider.AbstractFileObject#doGetInputStream()
*/
@Override
protected InputStream doGetInputStream() throws Exception {
return this.hdfs.open(this.path);
}
/**
* @see org.apache.commons.vfs2.provider.AbstractFileObject#doGetLastModifiedTime()
*/
@Override
protected long doGetLastModifiedTime() throws Exception {
if (null != this.stat) {
return this.stat.getModificationTime();
}
return -1;
}
/**
* @see org.apache.commons.vfs2.provider.AbstractFileObject#doGetRandomAccessContent
* (org.apache.commons.vfs2.util.RandomAccessMode)
*/
@Override
protected RandomAccessContent doGetRandomAccessContent(final RandomAccessMode mode) throws Exception {
if (mode.equals(RandomAccessMode.READWRITE)) {
throw new UnsupportedOperationException();
}
return new HdfsRandomAccessContent(this.path, this.hdfs);
}
/**
* @see org.apache.commons.vfs2.provider.AbstractFileObject#doGetType()
*/
@Override
protected FileType doGetType() throws Exception {
try {
doAttach();
if (null == stat) {
return FileType.IMAGINARY;
}
if (stat.isDirectory()) {
return FileType.FOLDER;
}
return FileType.FILE;
} catch (final FileNotFoundException fnfe) {
return FileType.IMAGINARY;
}
}
/**
* @see org.apache.commons.vfs2.provider.AbstractFileObject#doIsHidden()
*/
@Override
protected boolean doIsHidden() throws Exception {
return false;
}
/**
* @see org.apache.commons.vfs2.provider.AbstractFileObject#doIsReadable()
*/
@Override
protected boolean doIsReadable() throws Exception {
return true;
}
/**
* @see org.apache.commons.vfs2.provider.AbstractFileObject#doIsWriteable()
*/
@Override
protected boolean doIsWriteable() throws Exception {
return false;
}
/**
* @see org.apache.commons.vfs2.provider.AbstractFileObject#doListChildren()
*/
@Override
protected String[] doListChildren() throws Exception {
if (this.doGetType() != FileType.FOLDER) {
throw new FileNotFolderException(this);
}
final FileStatus[] files = this.hdfs.listStatus(this.path);
final String[] children = new String[files.length];
int i = 0;
for (final FileStatus status : files) {
children[i++] = status.getPath().getName();
}
return children;
}
/**
* @see org.apache.commons.vfs2.provider.AbstractFileObject#doListChildrenResolved()
*/
@Override
protected FileObject[] doListChildrenResolved() throws Exception {
if (this.doGetType() != FileType.FOLDER) {
return null;
}
final String[] children = doListChildren();
final FileObject[] fo = new FileObject[children.length];
for (int i = 0; i < children.length; i++) {
final Path p = new Path(this.path, children[i]);
fo[i] = this.fs.resolveFile(p.toUri().toString());
}
return fo;
}
/**
* @see org.apache.commons.vfs2.provider.AbstractFileObject#doRemoveAttribute(java.lang.String)
*/
@Override
protected void doRemoveAttribute(final String attrName) throws Exception {
throw new UnsupportedOperationException();
}
/**
* @see org.apache.commons.vfs2.provider.AbstractFileObject#doSetAttribute(java.lang.String, java.lang.Object)
*/
@Override
protected void doSetAttribute(final String attrName, final Object value) throws Exception {
throw new UnsupportedOperationException();
}
/**
* @see org.apache.commons.vfs2.provider.AbstractFileObject#doSetLastModifiedTime(long)
*/
@Override
protected boolean doSetLastModifiedTime(final long modtime) throws Exception {
throw new UnsupportedOperationException();
}
/**
* @see org.apache.commons.vfs2.provider.AbstractFileObject#exists()
* @return boolean true if file exists, false if not
*/
@Override
public boolean exists() throws FileSystemException {
try {
doAttach();
return this.stat != null;
} catch (final FileNotFoundException fne) {
return false;
} catch (final Exception e) {
throw new FileSystemException("Unable to check existance ", e);
}
}
}