INodeSymlink (Apache Hadoop HDFS 3.4.1.300-dep-1001 API)

java.lang.Object
- org.apache.hadoop.hdfs.server.namenode.INode
- - org.apache.hadoop.hdfs.server.namenode.INodeWithAdditionalFields
  - - org.apache.hadoop.hdfs.server.namenode.INodeSymlink

All Implemented Interfaces:

java.lang.Comparable<byte[]>, INodeAttributes, Diff.Element<byte[]>, org.apache.hadoop.util.LightWeightGSet.LinkedElement
```
@Private
public class INodeSymlink
extends INodeWithAdditionalFields
```
An INode representing a symbolic link.

Nested Class Summary
- Nested classes/interfaces inherited from class org.apache.hadoop.hdfs.server.namenode.INode
  INode.BlocksMapUpdateInfo, INode.Feature, INode.QuotaDelta, INode.ReclaimContext
- Nested classes/interfaces inherited from interface org.apache.hadoop.hdfs.server.namenode.INodeAttributes
  INodeAttributes.SnapshotCopy

Field Summary
- Fields inherited from class org.apache.hadoop.hdfs.server.namenode.INodeWithAdditionalFields
  features
- Fields inherited from class org.apache.hadoop.hdfs.server.namenode.INode
  LOG

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`void`	`accept(NamespaceVisitor visitor, int snapshot)`	Accept a visitor to visit this `INode`.
`void`	`addAclFeature(AclFeature f)`
`void`	`addXAttrFeature(XAttrFeature f)`
`INodeSymlink`	`asSymlink()`	Cast this inode to an `INodeSymlink`.
`void`	`cleanSubtree(INode.ReclaimContext reclaimContext, int snapshotId, int priorSnapshotId)`	Clean the subtree under this inode and collect the blocks from the descents for further block deletion/update.
`ContentSummaryComputationContext`	`computeContentSummary(int snapshotId, ContentSummaryComputationContext summary)`	Count subtree content summary with a `ContentCounts`.
`QuotaCounts`	`computeQuotaUsage(BlockStoragePolicySuite bsps, byte blockStoragePolicyId, boolean useCache, int lastSnapshotId)`	Count subtree `Quota.NAMESPACE` and `Quota.STORAGESPACE` usages.
`void`	`destroyAndCollectBlocks(INode.ReclaimContext reclaimContext)`	Destroy self and clear everything! If the INode is a file, this method collects its blocks for further block deletion.
`void`	`dumpTreeRecursively(java.io.PrintWriter out, java.lang.StringBuilder prefix, int snapshot)`	Dump tree recursively.
`byte`	`getLocalStoragePolicyID()`
`byte`	`getStoragePolicyID()`
`byte[]`	`getSymlink()`
`java.lang.String`	`getSymlinkString()`
`boolean`	`isSymlink()`	Check whether it's a symlink
`void`	`removeAclFeature()`
`void`	`removeXAttrFeature()`

Methods inherited from class org.apache.hadoop.hdfs.server.namenode.INodeWithAdditionalFields
addFeature, getAclFeature, getFeature, getFeatures, getFsPermissionShort, getId, getLocalNameBytes, getNext, getPermissionLong, getPermissionStatus, removeFeature, setAccessTime, setLocalName, setModificationTime, setNext, updateModificationTime

Methods inherited from class org.apache.hadoop.hdfs.server.namenode.INode
addSpaceConsumed, asDirectory, asFile, asReference, clear, compareTo, computeAndConvertContentSummary, computeContentSummary, computeQuotaUsage, computeQuotaUsage, dumpINode, dumpParentINodes, dumpTreeRecursively, dumpTreeRecursively, equals, getAccessTime, getAclFeature, getFsPermission, getFullPathAndObjectString, getFullPathName, getGroupName, getKey, getLocalName, getModificationTime, getObjectString, getParent, getParentReference, getParentString, getPathComponents, getPathComponents, getPathNames, getQuotaCounts, getSnapshotINode, getStoragePolicyIDForQuota, getUserName, getXAttrFeature, hashCode, isAncestorDirectory, isDeleted, isDirectory, isFile, isInCurrentState, isInLatestSnapshot, isLastReference, isQuotaSet, isReference, isSetStoragePolicy, setAccessTime, setModificationTime, setParent, setParentReference, shouldRecordInSrcSnapshot, toDetailString, toString

Methods inherited from class java.lang.Object
clone, finalize, getClass, notify, notifyAll, wait, wait, wait

- Method Detail
  - isSymlink
```
public boolean isSymlink()
```
    Description copied from class: INode
    
    Check whether it's a symlink
    
    Overrides:
    
    isSymlink in class INode
    
    Returns:
    
    true unconditionally.
  - asSymlink
```
public INodeSymlink asSymlink()
```
    Description copied from class: INode
    
    Cast this inode to an INodeSymlink.
    
    Overrides:
    
    asSymlink in class INode
    
    Returns:
    
    this object.
  - getSymlinkString
```
public java.lang.String getSymlinkString()
```
  - getSymlink
```
public byte[] getSymlink()
```
  - cleanSubtree
```
public void cleanSubtree(INode.ReclaimContext reclaimContext,
                         int snapshotId,
                         int priorSnapshotId)
```
    Description copied from class: INode
    Clean the subtree under this inode and collect the blocks from the descents for further block deletion/update. The current inode can either resides in the current tree or be stored as a snapshot copy.
```
 In general, we have the following rules. 
 1. When deleting a file/directory in the current tree, we have different 
 actions according to the type of the node to delete. 
 
 1.1 The current inode (this) is an INodeFile. 
 1.1.1 If prior is null, there is no snapshot taken on ancestors 
 before. Thus we simply destroy (i.e., to delete completely, no need to save 
 snapshot copy) the current INode and collect its blocks for further 
 cleansing.
 1.1.2 Else do nothing since the current INode will be stored as a snapshot
 copy.
 
 1.2 The current inode is an INodeDirectory.
 1.2.1 If prior is null, there is no snapshot taken on ancestors 
 before. Similarly, we destroy the whole subtree and collect blocks.
 1.2.2 Else do nothing with the current INode. Recursively clean its 
 children.
 
 1.3 The current inode is a file with snapshot.
 Call recordModification(..) to capture the current states.
 Mark the INode as deleted.
 
 1.4 The current inode is an INodeDirectory with snapshot feature.
 Call recordModification(..) to capture the current states. 
 Destroy files/directories created after the latest snapshot 
 (i.e., the inodes stored in the created list of the latest snapshot).
 Recursively clean remaining children. 

 2. When deleting a snapshot.
 2.1 To clean INodeFile: do nothing.
 2.2 To clean INodeDirectory: recursively clean its children.
 2.3 To clean INodeFile with snapshot: delete the corresponding snapshot in
 its diff list.
 2.4 To clean INodeDirectory with snapshot: delete the corresponding 
 snapshot in its diff list. Recursively clean its children.
 
```
    Specified by:
    
    cleanSubtree in class INode
    
    Parameters:
    
    reclaimContext - Record blocks and inodes that need to be reclaimed.
    
    snapshotId - The id of the snapshot to delete. Snapshot.CURRENT_STATE_ID means to delete the current file/directory.
    
    priorSnapshotId - The id of the latest snapshot before the to-be-deleted snapshot. When deleting a current inode, this parameter captures the latest snapshot.
  - destroyAndCollectBlocks
```
public void destroyAndCollectBlocks(INode.ReclaimContext reclaimContext)
```
    Description copied from class: INode
    
    Destroy self and clear everything! If the INode is a file, this method collects its blocks for further block deletion. If the INode is a directory, the method goes down the subtree and collects blocks from the descents, and clears its parent/children references as well. The method also clears the diff list if the INode contains snapshot diff list.
    
    Specified by:
    
    destroyAndCollectBlocks in class INode
    
    Parameters:
    
    reclaimContext - Record blocks and inodes that need to be reclaimed.
  - computeQuotaUsage
```
public QuotaCounts computeQuotaUsage(BlockStoragePolicySuite bsps,
                                     byte blockStoragePolicyId,
                                     boolean useCache,
                                     int lastSnapshotId)
```
    Description copied from class: INode
    Count subtree Quota.NAMESPACE and Quota.STORAGESPACE usages. With the existence of INodeReference, the same inode and its subtree may be referred by multiple INodeReference.WithName nodes and a INodeReference.DstReference node. To avoid circles while quota usage computation, we have the following rules:
```
 1. For a INodeReference.DstReference node, since the node must be in the current
 tree (or has been deleted as the end point of a series of rename 
 operations), we compute the quota usage of the referred node (and its 
 subtree) in the regular manner, i.e., including every inode in the current
 tree and in snapshot copies, as well as the size of diff list.
 
 2. For a INodeReference.WithName node, since the node must be in a snapshot, we 
 only count the quota usage for those nodes that still existed at the 
 creation time of the snapshot associated with the INodeReference.WithName node.
 We do not count in the size of the diff list.
 
```
    Specified by:
    
    computeQuotaUsage in class INode
    
    Parameters:
    
    bsps - Block storage policy suite to calculate intended storage type usage
    
    blockStoragePolicyId - block storage policy id of the current INode
    
    useCache - Whether to use cached quota usage. Note that INodeReference.WithName node never uses cache for its subtree.
    
    lastSnapshotId - Snapshot.CURRENT_STATE_ID indicates the computation is in the current tree. Otherwise the id indicates the computation range for a INodeReference.WithName node.
    
    Returns:
    
    The subtree quota counts.
  - computeContentSummary
```
public ContentSummaryComputationContext computeContentSummary(int snapshotId,
                                                              ContentSummaryComputationContext summary)
```
    Description copied from class: INode
    
    Count subtree content summary with a ContentCounts.
    
    Specified by:
    
    computeContentSummary in class INode
    
    Parameters:
    
    snapshotId - Specify the time range for the calculation. If this parameter equals to Snapshot.CURRENT_STATE_ID, the result covers both the current states and all the snapshots. Otherwise the result only covers all the files/directories contained in the specific snapshot.
    
    summary - the context object holding counts for the subtree.
    
    Returns:
    
    The same objects as summary.
  - dumpTreeRecursively
```
public void dumpTreeRecursively(java.io.PrintWriter out,
                                java.lang.StringBuilder prefix,
                                int snapshot)
```
    Description copied from class: INode
    
    Dump tree recursively.
    
    Overrides:
    
    dumpTreeRecursively in class INode
    
    prefix - The prefix string that each line should print.
  - accept
```
public void accept(NamespaceVisitor visitor,
                   int snapshot)
```
    Description copied from class: INode
    
    Accept a visitor to visit this INode.
    
    Overrides:
    
    accept in class INode
  - removeAclFeature
```
public void removeAclFeature()
```
    Overrides:
    
    removeAclFeature in class INodeWithAdditionalFields
  - addAclFeature
```
public void addAclFeature(AclFeature f)
```
    Overrides:
    
    addAclFeature in class INodeWithAdditionalFields
  - removeXAttrFeature
```
public void removeXAttrFeature()
```
    Overrides:
    
    removeXAttrFeature in class INodeWithAdditionalFields
  - addXAttrFeature
```
public void addXAttrFeature(XAttrFeature f)
```
    Overrides:
    
    addXAttrFeature in class INodeWithAdditionalFields
  - getStoragePolicyID
```
public byte getStoragePolicyID()
```
    Specified by:
    
    getStoragePolicyID in class INode
    
    Returns:
    
    the latest block storage policy id of the INode. Specifically, if a storage policy is directly specified on the INode then return the ID of that policy. Otherwise follow the latest parental path and return the ID of the first specified storage policy.
  - getLocalStoragePolicyID
```
public byte getLocalStoragePolicyID()
```
    Specified by:
    
    getLocalStoragePolicyID in class INode
    
    Returns:
    
    the storage policy directly specified on the INode. Return HdfsConstants.BLOCK_STORAGE_POLICY_ID_UNSPECIFIED if no policy has been specified.

Class INodeSymlink

Nested Class Summary

Nested classes/interfaces inherited from class org.apache.hadoop.hdfs.server.namenode.INode

Nested classes/interfaces inherited from interface org.apache.hadoop.hdfs.server.namenode.INodeAttributes

Field Summary

Fields inherited from class org.apache.hadoop.hdfs.server.namenode.INodeWithAdditionalFields

Fields inherited from class org.apache.hadoop.hdfs.server.namenode.INode

Method Summary

Methods inherited from class org.apache.hadoop.hdfs.server.namenode.INodeWithAdditionalFields

Methods inherited from class org.apache.hadoop.hdfs.server.namenode.INode

Methods inherited from class java.lang.Object

Method Detail

isSymlink

asSymlink

getSymlinkString

getSymlink

cleanSubtree

destroyAndCollectBlocks

computeQuotaUsage

computeContentSummary

dumpTreeRecursively

accept

removeAclFeature

addAclFeature

removeXAttrFeature

addXAttrFeature

getStoragePolicyID

getLocalStoragePolicyID