Package org.apache.hadoop.fs.viewfs

Class InodeTree<T>

java.lang.Object

org.apache.hadoop.fs.viewfs.InodeTree<T>

Type Parameters:

T - is AbstractFileSystem or FileSystem The two main methods are InodeTree(Configuration, String, URI, boolean) // constructor resolve(String, boolean)

@Private
@Unstable
public abstract class InodeTree<T>
extends Object

InodeTree implements a mount-table as a tree of inodes. It is used to implement ViewFs and ViewFileSystem. In order to use it the caller must subclass it and implement the abstract methods getTargetFileSystem(INodeDir), etc. The mountable is initialized from the config variables as specified in ViewFs

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	InodeTree.INodeLink<T>	An internal class to represent a mount link.
static class	InodeTree.MountPoint<T>
static class	InodeTree.ResolveResult<T>	Resolve returns ResolveResult.

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	InodeTree(Configuration config, String viewName, URI theUri, boolean initingUriAsFallbackOnNoMounts)	Create Inode Tree from the specified mount-table specified in Config.

Method Summary

Modifier and Type	Method	Description
protected InodeTree.ResolveResult<T>	buildResolveResultForRegexMountPoint(org.apache.hadoop.fs.viewfs.InodeTree.ResultKind resultKind, String resolvedPathStr, String targetOfResolvedPathStr, Path remainingPath)	Build resolve result.
String	getHomeDirPrefixValue()
List<InodeTree.MountPoint<T>>	getMountPoints()
InodeTree.INodeLink<T>	getRootFallbackLink()
protected abstract T	getTargetFileSystem(String settings, URI[] mergeFsURIs)
protected abstract T	getTargetFileSystem(org.apache.hadoop.fs.viewfs.InodeTree.INodeDir<T> dir)
protected abstract Function<URI,T>	initAndGetTargetFs()	The user of this class must subclass and implement the following 3 abstract methods.
boolean	isRootInternalDir()
InodeTree.ResolveResult<T>	resolve(String p, boolean resolveLastComponent)	Resolve the pathname p relative to root InodeDir.
protected InodeTree.ResolveResult<T>	tryResolveInRegexMountpoint(String srcPath, boolean resolveLastComponent)	Walk through all regex mount points to see whether the path match any regex expressions.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Details

InodeTree

protected InodeTree(Configuration config,
 String viewName,
 URI theUri,
 boolean initingUriAsFallbackOnNoMounts)
             throws UnsupportedFileSystemException,
URISyntaxException,
FileAlreadyExistsException,
IOException

Create Inode Tree from the specified mount-table specified in Config.

Parameters:

config - the mount table keys are prefixed with FsConstants.CONFIG_VIEWFS_PREFIX.

viewName - the name of the mount table if null use defaultMT name.

theUri - heUri.

initingUriAsFallbackOnNoMounts - initingUriAsFallbackOnNoMounts.

Throws:

UnsupportedFileSystemException - file system for uri is not found.

URISyntaxException - if the URI does not have an authority it is badly formed.

FileAlreadyExistsException - there is a file at the path specified or is discovered on one of its ancestors.

IOException - raised on errors performing I/O.

Method Details

initAndGetTargetFs

protected abstract Function<URI,T> initAndGetTargetFs()

The user of this class must subclass and implement the following 3 abstract methods.

Returns:

Function.

getTargetFileSystem

protected abstract T getTargetFileSystem(org.apache.hadoop.fs.viewfs.InodeTree.INodeDir<T> dir)
                                  throws URISyntaxException,
IOException

Throws:

URISyntaxException

IOException

getTargetFileSystem

protected abstract T getTargetFileSystem(String settings,
 URI[] mergeFsURIs)
                                  throws UnsupportedFileSystemException,
URISyntaxException,
IOException

Throws:

UnsupportedFileSystemException

URISyntaxException

IOException

isRootInternalDir

public boolean isRootInternalDir()

Returns:

true if the root represented as internalDir. In LinkMergeSlash, there will be root to root mapping. So, root does not represent as internalDir.

getRootFallbackLink

public InodeTree.INodeLink<T> getRootFallbackLink()

resolve

public InodeTree.ResolveResult<T> resolve(String p,
 boolean resolveLastComponent)
                                   throws IOException

Resolve the pathname p relative to root InodeDir.

Parameters:

p - - input path

resolveLastComponent - resolveLastComponent.

Returns:

ResolveResult which allows further resolution of the remaining path

Throws:

IOException - raised on errors performing I/O.

tryResolveInRegexMountpoint

protected InodeTree.ResolveResult<T> tryResolveInRegexMountpoint(String srcPath,
 boolean resolveLastComponent)

Walk through all regex mount points to see whether the path match any regex expressions. E.g. link: ^/user/(?<username>\\w+) => s3://$user.apache.com/_${user} srcPath: is /user/hadoop/dir1 resolveLastComponent: true then return value is s3://hadoop.apache.com/_hadoop

Parameters:

srcPath - srcPath.

resolveLastComponent - resolveLastComponent.

Returns:

ResolveResult.

buildResolveResultForRegexMountPoint

protected InodeTree.ResolveResult<T> buildResolveResultForRegexMountPoint(org.apache.hadoop.fs.viewfs.InodeTree.ResultKind resultKind,
 String resolvedPathStr,
 String targetOfResolvedPathStr,
 Path remainingPath)

Build resolve result. Here's an example Mountpoint: fs.viewfs.mounttable.mt .linkRegex.replaceresolveddstpath:_:-#.^/user/(??<username>\w+) Value: /targetTestRoot/$username Dir path to test: viewfs://mt/user/hadoop_user1/hadoop_dir1 Expect path: /targetTestRoot/hadoop-user1/hadoop_dir1 resolvedPathStr: /user/hadoop_user1 targetOfResolvedPathStr: /targetTestRoot/hadoop-user1 remainingPath: /hadoop_dir1

Parameters:

resultKind - resultKind.

resolvedPathStr - resolvedPathStr.

targetOfResolvedPathStr - targetOfResolvedPathStr.

remainingPath - remainingPath.

Returns:

targetFileSystem or null on exceptions.

getMountPoints

public List<InodeTree.MountPoint<T>> getMountPoints()

getHomeDirPrefixValue

public String getHomeDirPrefixValue()

Returns:

home dir value from mount table; null if no config value was found.