ZKProcedureUtil (Apache HBase 1.4.11 API)

java.lang.Object
- org.apache.hadoop.hbase.zookeeper.ZooKeeperListener
- - org.apache.hadoop.hbase.procedure.ZKProcedureUtil

All Implemented Interfaces:

Closeable, AutoCloseable
```
@InterfaceAudience.Private
public abstract class ZKProcedureUtil
extends ZooKeeperListener
implements Closeable
```
This is a shared ZooKeeper-based znode management utils for distributed procedure. All znode operations should go through the provided methods in coordinators and members. Layout of nodes in ZK is /hbase/[op name]/acquired/ [op instance] - op data/ /[nodes that have acquired] /reached/ [op instance]/ /[nodes that have completed] /abort/ [op instance] - failure data NOTE: while acquired and completed are znode dirs, abort is actually just a znode. Assumption here that procedure names are unique

Field Summary

Fields
Modifier and Type	Field and Description
`static String`	`ABORT_ZNODE_DEFAULT`
`protected String`	`abortZnode`
`static String`	`ACQUIRED_BARRIER_ZNODE_DEFAULT`
`protected String`	`acquiredZnode`
`String`	`baseZNode`
`static String`	`REACHED_BARRIER_ZNODE_DEFAULT`
`protected String`	`reachedZnode`

Fields inherited from class org.apache.hadoop.hbase.zookeeper.ZooKeeperListener
watcher

Constructor Summary

Constructors
Constructor and Description

ZKProcedureUtil(ZooKeeperWatcher watcher, String procDescription)
Top-level watcher/controller for procedures across the cluster.

Constructors
Constructor and Description
`ZKProcedureUtil(ZooKeeperWatcher watcher, String procDescription)` Top-level watcher/controller for procedures across the cluster.

Method Summary

Methods
Modifier and Type	Method and Description
`void`	`clearChildZNodes()`
`void`	`clearZNodes(String procedureName)`
`void`	`close()`
`static String`	`getAbortNode(ZKProcedureUtil controller, String opInstanceName)` Get the full znode path for the node used by the coordinator or member to trigger an abort of the global barrier acquisition or execution in subprocedures.
`String`	`getAbortZnode()`
`String`	`getAbortZNode(String opInstanceName)`
`static String`	`getAcquireBarrierNode(ZKProcedureUtil controller, String opInstanceName)` Get the full znode path for the node used by the coordinator to trigger a global barrier acquire on each subprocedure.
`String`	`getAcquiredBarrier()`
`String`	`getAcquiredBarrierNode(String opInstanceName)`
`String`	`getBaseZnode()`
`String`	`getReachedBarrierNode(String opInstanceName)`
`static String`	`getReachedBarrierNode(ZKProcedureUtil controller, String opInstanceName)` Get the full znode path for the node used by the coordinator to trigger a global barrier execution and release on each subprocedure.
`ZooKeeperWatcher`	`getWatcher()`
`boolean`	`isAbortPathNode(String path)` Is this in the procedure barrier abort znode path
`protected void`	`logZKTree(String root, String prefix)` Helper method to print the current state of the ZK tree.

Methods inherited from class org.apache.hadoop.hbase.zookeeper.ZooKeeperListener
nodeChildrenChanged, nodeCreated, nodeDataChanged, nodeDeleted

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

- Field Detail
  - ACQUIRED_BARRIER_ZNODE_DEFAULT
```
public static final String ACQUIRED_BARRIER_ZNODE_DEFAULT
```
    See Also:
    Constant Field Values
  - REACHED_BARRIER_ZNODE_DEFAULT
```
public static final String REACHED_BARRIER_ZNODE_DEFAULT
```
    See Also:
    Constant Field Values
  - ABORT_ZNODE_DEFAULT
```
public static final String ABORT_ZNODE_DEFAULT
```
    See Also:
    Constant Field Values
  - baseZNode
```
public final String baseZNode
```
  - acquiredZnode
```
protected final String acquiredZnode
```
  - reachedZnode
```
protected final String reachedZnode
```
  - abortZnode
```
protected final String abortZnode
```
- Constructor Detail
  - ZKProcedureUtil
```
public ZKProcedureUtil(ZooKeeperWatcher watcher,
               String procDescription)
                throws org.apache.zookeeper.KeeperException
```
    Top-level watcher/controller for procedures across the cluster.
    On instantiation, this ensures the procedure znodes exist. This however requires the passed in watcher has been started.
    
    Parameters:
    watcher - watcher for the cluster ZK. Owned by this and closed via close()
    procDescription - name of the znode describing the procedure to run
    
    Throws:
    
    org.apache.zookeeper.KeeperException - when the procedure znodes cannot be created
- Method Detail
  - close
```
public void close()
           throws IOException
```
    Specified by:
    
    close in interface Closeable
    
    Specified by:
    
    close in interface AutoCloseable
    
    Throws:
    
    IOException
  - getAcquiredBarrierNode
```
public String getAcquiredBarrierNode(String opInstanceName)
```
  - getReachedBarrierNode
```
public String getReachedBarrierNode(String opInstanceName)
```
  - getAbortZNode
```
public String getAbortZNode(String opInstanceName)
```
  - getAbortZnode
```
public String getAbortZnode()
```
  - getBaseZnode
```
public String getBaseZnode()
```
  - getAcquiredBarrier
```
public String getAcquiredBarrier()
```
  - getAcquireBarrierNode
```
public static String getAcquireBarrierNode(ZKProcedureUtil controller,
                           String opInstanceName)
```
    Get the full znode path for the node used by the coordinator to trigger a global barrier acquire on each subprocedure.
    
    Parameters:
    controller - controller running the procedure
    opInstanceName - name of the running procedure instance (not the procedure description).
    
    Returns:
    full znode path to the prepare barrier/start node
  - getReachedBarrierNode
```
public static String getReachedBarrierNode(ZKProcedureUtil controller,
                           String opInstanceName)
```
    Get the full znode path for the node used by the coordinator to trigger a global barrier execution and release on each subprocedure.
    
    Parameters:
    controller - controller running the procedure
    opInstanceName - name of the running procedure instance (not the procedure description).
    
    Returns:
    full znode path to the commit barrier
  - getAbortNode
```
public static String getAbortNode(ZKProcedureUtil controller,
                  String opInstanceName)
```
    Get the full znode path for the node used by the coordinator or member to trigger an abort of the global barrier acquisition or execution in subprocedures.
    
    Parameters:
    controller - controller running the procedure
    opInstanceName - name of the running procedure instance (not the procedure description).
    
    Returns:
    full znode path to the abort znode
  - getWatcher
```
public ZooKeeperWatcher getWatcher()
```
    Overrides:
    
    getWatcher in class ZooKeeperListener
    
    Returns:
    The watcher associated with this listener
  - isAbortPathNode
```
public boolean isAbortPathNode(String path)
```
    Is this in the procedure barrier abort znode path
  - logZKTree
```
protected void logZKTree(String root,
             String prefix)
                  throws org.apache.zookeeper.KeeperException
```
    Helper method to print the current state of the ZK tree.
    
    Throws:
    
    org.apache.zookeeper.KeeperException - if an unexpected exception occurs
    See Also:
    logZKTree(String)
  - clearChildZNodes
```
public void clearChildZNodes()
                      throws org.apache.zookeeper.KeeperException
```
    Throws:
    
    org.apache.zookeeper.KeeperException
  - clearZNodes
```
public void clearZNodes(String procedureName)
                 throws org.apache.zookeeper.KeeperException
```
    Throws:
    
    org.apache.zookeeper.KeeperException

Class ZKProcedureUtil

Field Summary

Fields inherited from class org.apache.hadoop.hbase.zookeeper.ZooKeeperListener

Constructor Summary

Method Summary

Methods inherited from class org.apache.hadoop.hbase.zookeeper.ZooKeeperListener

Methods inherited from class java.lang.Object

Field Detail

ACQUIRED_BARRIER_ZNODE_DEFAULT

REACHED_BARRIER_ZNODE_DEFAULT

ABORT_ZNODE_DEFAULT

baseZNode

acquiredZnode

reachedZnode

abortZnode

Constructor Detail

ZKProcedureUtil

Method Detail

close

getAcquiredBarrierNode

getReachedBarrierNode

getAbortZNode

getAbortZnode

getBaseZnode

getAcquiredBarrier

getAcquireBarrierNode

getReachedBarrierNode

getAbortNode

getWatcher

isAbortPathNode

logZKTree

clearChildZNodes

clearZNodes