ZKAssign (Apache HBase 1.2.12 API)

java.lang.Object
- org.apache.hadoop.hbase.zookeeper.ZKAssign

```
@InterfaceAudience.Private
public class ZKAssign
extends Object
```
Utility class for doing region assignment in ZooKeeper. This class extends stuff done in ZKUtil to cover specific assignment operations.
Contains only static methods and constants.
Used by both the Master and RegionServer.
All valid transitions outlined below:
MASTER
1. Master creates an unassigned node as OFFLINE. - Cluster startup and table enabling.
2. Master forces an existing unassigned node to OFFLINE. - RegionServer failure. - Allows transitions from all states to OFFLINE.
3. Master deletes an unassigned node that was in a OPENED state. - Normal region transitions. Besides cluster startup, no other deletions of unassigned nodes is allowed.
4. Master deletes all unassigned nodes regardless of state. - Cluster startup before any assignment happens.
REGIONSERVER
1. RegionServer creates an unassigned node as CLOSING. - All region closes will do this in response to a CLOSE RPC from Master. - A node can never be transitioned to CLOSING, only created.
2. RegionServer transitions an unassigned node from CLOSING to CLOSED. - Normal region closes. CAS operation.
3. RegionServer transitions an unassigned node from OFFLINE to OPENING. - All region opens will do this in response to an OPEN RPC from the Master. - Normal region opens. CAS operation.
4. RegionServer transitions an unassigned node from OPENING to OPENED. - Normal region opens. CAS operation.

Field Summary

Fields
Modifier and Type Field and Description

private static org.apache.commons.logging.Log LOG

Fields
Modifier and Type	Field and Description
`private static org.apache.commons.logging.Log`	`LOG`

Constructor Summary

Constructors
Constructor and Description

ZKAssign()

Constructors
Constructor and Description
`ZKAssign()`

Method Summary

Methods
Modifier and Type	Method and Description
`static void`	`asyncCreateNodeOffline(ZooKeeperWatcher zkw, HRegionInfo region, ServerName serverName, org.apache.zookeeper.AsyncCallback.StringCallback cb, Object ctx)` Creates an unassigned node in the OFFLINE state for the specified region.
`static void`	`blockUntilNoRIT(ZooKeeperWatcher zkw)` Blocks until there are no node in regions in transition.
`static void`	`blockUntilRIT(ZooKeeperWatcher zkw)` Blocks until there is at least one node in regions in transition.
`static boolean`	`checkClosingState(ZooKeeperWatcher zkw, HRegionInfo region, int expectedVersion)`
`static int`	`confirmNodeOpening(ZooKeeperWatcher zkw, HRegionInfo region, ServerName serverName, int expectedVersion)` Confirm an existing unassigned node for the specified region which is currently in the OPENING state to be still in the OPENING state on the specified server.
`static int`	`createNodeClosing(ZooKeeperWatcher zkw, HRegionInfo region, ServerName serverName)` Creates a new unassigned node in the CLOSING state for the specified region.
`static void`	`createNodeOffline(ZooKeeperWatcher zkw, HRegionInfo region, ServerName serverName)` Creates a new unassigned node in the OFFLINE state for the specified region.
`static void`	`createNodeOffline(ZooKeeperWatcher zkw, HRegionInfo region, ServerName serverName, EventType event)`
`static int`	`createOrForceNodeOffline(ZooKeeperWatcher zkw, HRegionInfo region, ServerName serverName)` Creates or force updates an unassigned node to the OFFLINE state for the specified region.
`static void`	`deleteAllNodes(ZooKeeperWatcher zkw)` Deletes all unassigned nodes regardless of their state.
`static boolean`	`deleteClosedNode(ZooKeeperWatcher zkw, String encodedRegionName, ServerName sn)` Deletes an existing unassigned node that is in the CLOSED state for the specified region.
`static boolean`	`deleteClosingNode(ZooKeeperWatcher zkw, HRegionInfo region, ServerName sn)` Deletes an existing unassigned node that is in the CLOSING state for the specified region.
`static boolean`	`deleteNode(ZooKeeperWatcher zkw, String encodedRegionName, EventType expectedState, int expectedVersion)` Deletes an existing unassigned node that is in the specified state for the specified region.
`static boolean`	`deleteNode(ZooKeeperWatcher zkw, String encodedRegionName, EventType expectedState, ServerName sn)` Deletes an existing unassigned node that is in the specified state for the specified region.
`static boolean`	`deleteNode(ZooKeeperWatcher zkw, String encodedRegionName, EventType expectedState, ServerName serverName, int expectedVersion)` Deletes an existing unassigned node that is in the specified state for the specified region.
`static void`	`deleteNodeFailSilent(ZooKeeperWatcher watcher, HRegionInfo regionInfo)` Delete the assignment node regardless of its current state.
`static boolean`	`deleteOfflineNode(ZooKeeperWatcher zkw, String encodedRegionName, ServerName sn)` Deletes an existing unassigned node that is in the OFFLINE state for the specified region.
`static boolean`	`deleteOpenedNode(ZooKeeperWatcher zkw, String encodedRegionName, ServerName sn)` Deletes an existing unassigned node that is in the OPENED state for the specified region.
`static byte[]`	`getData(ZooKeeperWatcher zkw, String pathOrRegionName)` Gets the current data in the unassigned node for the specified region name or fully-qualified path.
`static byte[]`	`getDataAndWatch(ZooKeeperWatcher zkw, String pathOrRegionName, org.apache.zookeeper.data.Stat stat)` Gets the current data in the unassigned node for the specified region name or fully-qualified path.
`static byte[]`	`getDataNoWatch(ZooKeeperWatcher zkw, String pathOrRegionName, org.apache.zookeeper.data.Stat stat)` Gets the current data in the unassigned node for the specified region name or fully-qualified path.
`static String`	`getNodeName(ZooKeeperWatcher zkw, String regionName)` Gets the full path node name for the unassigned node for the specified region.
`static String`	`getPath(ZooKeeperWatcher zkw, String pathOrRegionName)`
`static String`	`getRegionName(ZooKeeperWatcher zkw, String path)` Gets the region name from the full path node name of an unassigned node.
`private static RegionTransition`	`getRegionTransition(byte[] bytes)`
`static int`	`getVersion(ZooKeeperWatcher zkw, HRegionInfo region)` Get the version of the specified znode
`(package private) static String`	`toString(byte[] znodeBytes)` Presume bytes are serialized unassigned data structure
`static int`	`transitionNode(ZooKeeperWatcher zkw, HRegionInfo region, ServerName serverName, EventType beginState, EventType endState, int expectedVersion)` Method that actually performs unassigned node transitions.
`static int`	`transitionNode(ZooKeeperWatcher zkw, HRegionInfo region, ServerName serverName, EventType beginState, EventType endState, int expectedVersion, byte[] payload)`
`static int`	`transitionNodeClosed(ZooKeeperWatcher zkw, HRegionInfo region, ServerName serverName, int expectedVersion)` Transitions an existing unassigned node for the specified region which is currently in the CLOSING state to be in the CLOSED state.
`static int`	`transitionNodeOpened(ZooKeeperWatcher zkw, HRegionInfo region, ServerName serverName, int expectedVersion)` Transitions an existing unassigned node for the specified region which is currently in the OPENING state to be in the OPENED state.
`static int`	`transitionNodeOpening(ZooKeeperWatcher zkw, HRegionInfo region, ServerName serverName)` Transitions an existing unassigned node for the specified region which is currently in the OFFLINE state to be in the OPENING state.
`static int`	`transitionNodeOpening(ZooKeeperWatcher zkw, HRegionInfo region, ServerName serverName, EventType beginState)`

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

- Field Detail
  - LOG
```
private static final org.apache.commons.logging.Log LOG
```
- Constructor Detail
  - ZKAssign
```
public ZKAssign()
```
- Method Detail
  - getNodeName
```
public static String getNodeName(ZooKeeperWatcher zkw,
                 String regionName)
```
    Gets the full path node name for the unassigned node for the specified region.
    
    Parameters:
    zkw - zk reference
    regionName - region name
    
    Returns:
    full path node name
  - getRegionName
```
public static String getRegionName(ZooKeeperWatcher zkw,
                   String path)
```
    Gets the region name from the full path node name of an unassigned node.
    
    Parameters:
    path - full zk path
    
    Returns:
    region name
  - createNodeOffline
```
public static void createNodeOffline(ZooKeeperWatcher zkw,
                     HRegionInfo region,
                     ServerName serverName)
                              throws org.apache.zookeeper.KeeperException,
                                     org.apache.zookeeper.KeeperException.NodeExistsException
```
    Creates a new unassigned node in the OFFLINE state for the specified region.
    Does not transition nodes from other states. If a node already exists for this region, a KeeperException.NodeExistsException will be thrown.
    Sets a watcher on the unassigned region node if the method is successful.
    This method should only be used during cluster startup and the enabling of a table.
    
    Parameters:
    zkw - zk reference
    region - region to be created as offline
    serverName - server transition will happen on
    
    Throws:
    
    org.apache.zookeeper.KeeperException - if unexpected zookeeper exception
    
    KeeperException.NodeExistsException - if node already exists
  - createNodeOffline
```
public static void createNodeOffline(ZooKeeperWatcher zkw,
                     HRegionInfo region,
                     ServerName serverName,
                     EventType event)
                              throws org.apache.zookeeper.KeeperException,
                                     org.apache.zookeeper.KeeperException.NodeExistsException
```
    Throws:
    
    org.apache.zookeeper.KeeperException
    
    org.apache.zookeeper.KeeperException.NodeExistsException
  - asyncCreateNodeOffline
```
public static void asyncCreateNodeOffline(ZooKeeperWatcher zkw,
                          HRegionInfo region,
                          ServerName serverName,
                          org.apache.zookeeper.AsyncCallback.StringCallback cb,
                          Object ctx)
                                   throws org.apache.zookeeper.KeeperException
```
    Creates an unassigned node in the OFFLINE state for the specified region.
    Runs asynchronously. Depends on no pre-existing znode.
    Sets a watcher on the unassigned region node.
    
    Parameters:
    zkw - zk reference
    region - region to be created as offline
    serverName - server transition will happen on
    cb -
    ctx -
    
    Throws:
    
    org.apache.zookeeper.KeeperException - if unexpected zookeeper exception
    
    KeeperException.NodeExistsException - if node already exists
  - createOrForceNodeOffline
```
public static int createOrForceNodeOffline(ZooKeeperWatcher zkw,
                           HRegionInfo region,
                           ServerName serverName)
                                    throws org.apache.zookeeper.KeeperException
```
    Creates or force updates an unassigned node to the OFFLINE state for the specified region.
    Attempts to create the node but if it exists will force it to transition to and OFFLINE state.
    Sets a watcher on the unassigned region node if the method is successful.
    This method should be used when assigning a region.
    
    Parameters:
    zkw - zk reference
    region - region to be created as offline
    serverName - server transition will happen on
    
    Returns:
    the version of the znode created in OFFLINE state, -1 if unsuccessful.
    
    Throws:
    
    org.apache.zookeeper.KeeperException - if unexpected zookeeper exception
    
    KeeperException.NodeExistsException - if node already exists
  - deleteOpenedNode
```
public static boolean deleteOpenedNode(ZooKeeperWatcher zkw,
                       String encodedRegionName,
                       ServerName sn)
                                throws org.apache.zookeeper.KeeperException,
                                       org.apache.zookeeper.KeeperException.NoNodeException
```
    Deletes an existing unassigned node that is in the OPENED state for the specified region.
    If a node does not already exist for this region, a KeeperException.NoNodeException will be thrown.
    No watcher is set whether this succeeds or not.
    Returns false if the node was not in the proper state but did exist.
    This method is used during normal region transitions when a region finishes successfully opening. This is the Master acknowledging completion of the specified regions transition.
    
    Parameters:
    zkw - zk reference
    encodedRegionName - opened region to be deleted from zk
    sn - the expected region transition target server name
    
    Throws:
    
    org.apache.zookeeper.KeeperException - if unexpected zookeeper exception
    
    KeeperException.NoNodeException - if node does not exist
  - deleteOfflineNode
```
public static boolean deleteOfflineNode(ZooKeeperWatcher zkw,
                        String encodedRegionName,
                        ServerName sn)
                                 throws org.apache.zookeeper.KeeperException,
                                        org.apache.zookeeper.KeeperException.NoNodeException
```
    Deletes an existing unassigned node that is in the OFFLINE state for the specified region.
    If a node does not already exist for this region, a KeeperException.NoNodeException will be thrown.
    No watcher is set whether this succeeds or not.
    Returns false if the node was not in the proper state but did exist.
    This method is used during master failover when the regions on an RS that has died are all set to OFFLINE before being processed.
    
    Parameters:
    zkw - zk reference
    encodedRegionName - closed region to be deleted from zk
    sn - the expected region transition target server name
    
    Throws:
    
    org.apache.zookeeper.KeeperException - if unexpected zookeeper exception
    
    KeeperException.NoNodeException - if node does not exist
  - deleteClosedNode
```
public static boolean deleteClosedNode(ZooKeeperWatcher zkw,
                       String encodedRegionName,
                       ServerName sn)
                                throws org.apache.zookeeper.KeeperException,
                                       org.apache.zookeeper.KeeperException.NoNodeException
```
    Deletes an existing unassigned node that is in the CLOSED state for the specified region.
    If a node does not already exist for this region, a KeeperException.NoNodeException will be thrown.
    No watcher is set whether this succeeds or not.
    Returns false if the node was not in the proper state but did exist.
    This method is used during table disables when a region finishes successfully closing. This is the Master acknowledging completion of the specified regions transition to being closed.
    
    Parameters:
    zkw - zk reference
    encodedRegionName - closed region to be deleted from zk
    sn - the expected region transition target server name
    
    Throws:
    
    org.apache.zookeeper.KeeperException - if unexpected zookeeper exception
    
    KeeperException.NoNodeException - if node does not exist
  - deleteClosingNode
```
public static boolean deleteClosingNode(ZooKeeperWatcher zkw,
                        HRegionInfo region,
                        ServerName sn)
                                 throws org.apache.zookeeper.KeeperException,
                                        org.apache.zookeeper.KeeperException.NoNodeException
```
    Deletes an existing unassigned node that is in the CLOSING state for the specified region.
    If a node does not already exist for this region, a KeeperException.NoNodeException will be thrown.
    No watcher is set whether this succeeds or not.
    Returns false if the node was not in the proper state but did exist.
    This method is used during table disables when a region finishes successfully closing. This is the Master acknowledging completion of the specified regions transition to being closed.
    
    Parameters:
    zkw - zk reference
    region - closing region to be deleted from zk
    sn - the expected region transition target server name
    
    Throws:
    
    org.apache.zookeeper.KeeperException - if unexpected zookeeper exception
    
    KeeperException.NoNodeException - if node does not exist
  - deleteNode
```
public static boolean deleteNode(ZooKeeperWatcher zkw,
                 String encodedRegionName,
                 EventType expectedState,
                 ServerName sn)
                          throws org.apache.zookeeper.KeeperException,
                                 org.apache.zookeeper.KeeperException.NoNodeException
```
    Deletes an existing unassigned node that is in the specified state for the specified region.
    If a node does not already exist for this region, a KeeperException.NoNodeException will be thrown.
    No watcher is set whether this succeeds or not.
    Returns false if the node was not in the proper state but did exist.
    This method is used when a region finishes opening/closing. The Master acknowledges completion of the specified regions transition to being closed/opened.
    
    Parameters:
    zkw - zk reference
    encodedRegionName - region to be deleted from zk
    expectedState - state region must be in for delete to complete
    sn - the expected region transition target server name
    
    Throws:
    
    org.apache.zookeeper.KeeperException - if unexpected zookeeper exception
    
    KeeperException.NoNodeException - if node does not exist
  - deleteNode
```
public static boolean deleteNode(ZooKeeperWatcher zkw,
                 String encodedRegionName,
                 EventType expectedState,
                 int expectedVersion)
                          throws org.apache.zookeeper.KeeperException,
                                 org.apache.zookeeper.KeeperException.NoNodeException
```
    Deletes an existing unassigned node that is in the specified state for the specified region.
    If a node does not already exist for this region, a KeeperException.NoNodeException will be thrown.
    No watcher is set whether this succeeds or not.
    Returns false if the node was not in the proper state but did exist.
    This method is used when a region finishes opening/closing. The Master acknowledges completion of the specified regions transition to being closed/opened.
    
    Parameters:
    zkw - zk reference
    encodedRegionName - region to be deleted from zk
    expectedState - state region must be in for delete to complete
    expectedVersion - of the znode that is to be deleted. If expectedVersion need not be compared while deleting the znode pass -1
    
    Throws:
    
    org.apache.zookeeper.KeeperException - if unexpected zookeeper exception
    
    KeeperException.NoNodeException - if node does not exist
  - deleteNode
```
public static boolean deleteNode(ZooKeeperWatcher zkw,
                 String encodedRegionName,
                 EventType expectedState,
                 ServerName serverName,
                 int expectedVersion)
                          throws org.apache.zookeeper.KeeperException,
                                 org.apache.zookeeper.KeeperException.NoNodeException
```
    Deletes an existing unassigned node that is in the specified state for the specified region.
    If a node does not already exist for this region, a KeeperException.NoNodeException will be thrown.
    No watcher is set whether this succeeds or not.
    Returns false if the node was not in the proper state but did exist.
    This method is used when a region finishes opening/closing. The Master acknowledges completion of the specified regions transition to being closed/opened.
    
    Parameters:
    zkw - zk reference
    encodedRegionName - region to be deleted from zk
    expectedState - state region must be in for delete to complete
    serverName - the expected region transition target server name
    expectedVersion - of the znode that is to be deleted. If expectedVersion need not be compared while deleting the znode pass -1
    
    Throws:
    
    org.apache.zookeeper.KeeperException - if unexpected zookeeper exception
    
    KeeperException.NoNodeException - if node does not exist
  - deleteAllNodes
```
public static void deleteAllNodes(ZooKeeperWatcher zkw)
                           throws org.apache.zookeeper.KeeperException
```
    Deletes all unassigned nodes regardless of their state.
    No watchers are set.
    This method is used by the Master during cluster startup to clear out any existing state from other cluster runs.
    
    Parameters:
    zkw - zk reference
    
    Throws:
    
    org.apache.zookeeper.KeeperException - if unexpected zookeeper exception
  - createNodeClosing
```
public static int createNodeClosing(ZooKeeperWatcher zkw,
                    HRegionInfo region,
                    ServerName serverName)
                             throws org.apache.zookeeper.KeeperException,
                                    org.apache.zookeeper.KeeperException.NodeExistsException
```
    Creates a new unassigned node in the CLOSING state for the specified region.
    Does not transition nodes from any states. If a node already exists for this region, a KeeperException.NodeExistsException will be thrown.
    If creation is successful, returns the version number of the CLOSING node created.
    Set a watch.
    This method should only be used by a Master when initiating a close of a region before sending a close request to the region server.
    
    Parameters:
    zkw - zk reference
    region - region to be created as closing
    serverName - server transition will happen on
    
    Returns:
    version of node after transition, -1 if unsuccessful transition
    
    Throws:
    
    org.apache.zookeeper.KeeperException - if unexpected zookeeper exception
    
    KeeperException.NodeExistsException - if node already exists
  - transitionNodeClosed
```
public static int transitionNodeClosed(ZooKeeperWatcher zkw,
                       HRegionInfo region,
                       ServerName serverName,
                       int expectedVersion)
                                throws org.apache.zookeeper.KeeperException
```
    Transitions an existing unassigned node for the specified region which is currently in the CLOSING state to be in the CLOSED state.
    Does not transition nodes from other states. If for some reason the node could not be transitioned, the method returns -1. If the transition is successful, the version of the node after transition is returned.
    This method can fail and return false for three different reasons:
    - Unassigned node for this region does not exist
    - Unassigned node for this region is not in CLOSING state
    - After verifying CLOSING state, update fails because of wrong version (someone else already transitioned the node)
    Does not set any watches.
    This method should only be used by a RegionServer when initiating a close of a region after receiving a CLOSE RPC from the Master.
    Parameters:
    zkw - zk reference
    region - region to be transitioned to closed
    serverName - server transition happens on
    
    Returns:
    version of node after transition, -1 if unsuccessful transition
    
    Throws:
    
    org.apache.zookeeper.KeeperException - if unexpected zookeeper exception
  - transitionNodeOpening
```
public static int transitionNodeOpening(ZooKeeperWatcher zkw,
                        HRegionInfo region,
                        ServerName serverName)
                                 throws org.apache.zookeeper.KeeperException
```
    Transitions an existing unassigned node for the specified region which is currently in the OFFLINE state to be in the OPENING state.
    Does not transition nodes from other states. If for some reason the node could not be transitioned, the method returns -1. If the transition is successful, the version of the node written as OPENING is returned.
    This method can fail and return -1 for three different reasons:
    - Unassigned node for this region does not exist
    - Unassigned node for this region is not in OFFLINE state
    - After verifying OFFLINE state, update fails because of wrong version (someone else already transitioned the node)
    Does not set any watches.
    This method should only be used by a RegionServer when initiating an open of a region after receiving an OPEN RPC from the Master.
    Parameters:
    zkw - zk reference
    region - region to be transitioned to opening
    serverName - server transition happens on
    
    Returns:
    version of node after transition, -1 if unsuccessful transition
    
    Throws:
    
    org.apache.zookeeper.KeeperException - if unexpected zookeeper exception
  - transitionNodeOpening
```
public static int transitionNodeOpening(ZooKeeperWatcher zkw,
                        HRegionInfo region,
                        ServerName serverName,
                        EventType beginState)
                                 throws org.apache.zookeeper.KeeperException
```
    Throws:
    
    org.apache.zookeeper.KeeperException
  - confirmNodeOpening
```
public static int confirmNodeOpening(ZooKeeperWatcher zkw,
                     HRegionInfo region,
                     ServerName serverName,
                     int expectedVersion)
                              throws org.apache.zookeeper.KeeperException
```
    Confirm an existing unassigned node for the specified region which is currently in the OPENING state to be still in the OPENING state on the specified server.
    If for some reason the check fails, the method returns -1. Otherwise, the version of the node (same as the expected version) is returned.
    This method can fail and return -1 for three different reasons:
    - Unassigned node for this region does not exist
    - Unassigned node for this region is not in OPENING state
    - After verifying OPENING state, the server name or the version of the doesn't match)
    Does not set any watches.
    This method should only be used by a RegionServer when initiating an open of a region after receiving an OPEN RPC from the Master.
    Parameters:
    zkw - zk reference
    region - region to be transitioned to opening
    serverName - server transition happens on
    
    Returns:
    version of node after transition, -1 if unsuccessful transition
    
    Throws:
    
    org.apache.zookeeper.KeeperException - if unexpected zookeeper exception
  - transitionNodeOpened
```
public static int transitionNodeOpened(ZooKeeperWatcher zkw,
                       HRegionInfo region,
                       ServerName serverName,
                       int expectedVersion)
                                throws org.apache.zookeeper.KeeperException
```
    Transitions an existing unassigned node for the specified region which is currently in the OPENING state to be in the OPENED state.
    Does not transition nodes from other states. If for some reason the node could not be transitioned, the method returns -1. If the transition is successful, the version of the node after transition is returned.
    This method can fail and return false for three different reasons:
    - Unassigned node for this region does not exist
    - Unassigned node for this region is not in OPENING state
    - After verifying OPENING state, update fails because of wrong version (this should never actually happen since an RS only does this transition following a transition to OPENING. if two RS are conflicting, one would fail the original transition to OPENING and not this transition)
    Does not set any watches.
    This method should only be used by a RegionServer when completing the open of a region.
    Parameters:
    zkw - zk reference
    region - region to be transitioned to opened
    serverName - server transition happens on
    
    Returns:
    version of node after transition, -1 if unsuccessful transition
    
    Throws:
    
    org.apache.zookeeper.KeeperException - if unexpected zookeeper exception
  - checkClosingState
```
public static boolean checkClosingState(ZooKeeperWatcher zkw,
                        HRegionInfo region,
                        int expectedVersion)
                                 throws org.apache.zookeeper.KeeperException
```
    Parameters:
    zkw - zk reference
    region - region to be closed
    expectedVersion - expected version of the znode
    
    Returns:
    true if the znode exists, has the right version and the right state. False otherwise.
    
    Throws:
    
    org.apache.zookeeper.KeeperException
  - transitionNode
```
public static int transitionNode(ZooKeeperWatcher zkw,
                 HRegionInfo region,
                 ServerName serverName,
                 EventType beginState,
                 EventType endState,
                 int expectedVersion)
                          throws org.apache.zookeeper.KeeperException
```
    Method that actually performs unassigned node transitions.
    Attempts to transition the unassigned node for the specified region from the expected state to the state in the specified transition data.
    Method first reads existing data and verifies it is in the expected state. If the node does not exist or the node is not in the expected state, the method returns -1. If the transition is successful, the version number of the node following the transition is returned.
    If the read state is what is expected, it attempts to write the new state and data into the node. When doing this, it includes the expected version (determined when the existing state was verified) to ensure that only one transition is successful. If there is a version mismatch, the method returns -1.
    If the write is successful, no watch is set and the method returns true.
    
    Parameters:
    zkw - zk reference
    region - region to be transitioned to opened
    serverName - server transition happens on
    endState - state to transition node to if all checks pass
    beginState - state the node must currently be in to do transition
    expectedVersion - expected version of data before modification, or -1
    
    Returns:
    version of node after transition, -1 if unsuccessful transition
    
    Throws:
    
    org.apache.zookeeper.KeeperException - if unexpected zookeeper exception
  - transitionNode
```
public static int transitionNode(ZooKeeperWatcher zkw,
                 HRegionInfo region,
                 ServerName serverName,
                 EventType beginState,
                 EventType endState,
                 int expectedVersion,
                 byte[] payload)
                          throws org.apache.zookeeper.KeeperException
```
    Throws:
    
    org.apache.zookeeper.KeeperException
  - getRegionTransition
```
private static RegionTransition getRegionTransition(byte[] bytes)
                                             throws org.apache.zookeeper.KeeperException
```
    Throws:
    
    org.apache.zookeeper.KeeperException
  - getData
```
public static byte[] getData(ZooKeeperWatcher zkw,
             String pathOrRegionName)
                      throws org.apache.zookeeper.KeeperException
```
    Gets the current data in the unassigned node for the specified region name or fully-qualified path.
    Returns null if the region does not currently have a node.
    Sets a watch on the node if the node exists.
    
    Parameters:
    zkw - zk reference
    pathOrRegionName - fully-specified path or region name
    
    Returns:
    znode content
    
    Throws:
    
    org.apache.zookeeper.KeeperException - if unexpected zookeeper exception
  - getDataAndWatch
```
public static byte[] getDataAndWatch(ZooKeeperWatcher zkw,
                     String pathOrRegionName,
                     org.apache.zookeeper.data.Stat stat)
                              throws org.apache.zookeeper.KeeperException
```
    Gets the current data in the unassigned node for the specified region name or fully-qualified path.
    Returns null if the region does not currently have a node.
    Sets a watch on the node if the node exists.
    
    Parameters:
    zkw - zk reference
    pathOrRegionName - fully-specified path or region name
    stat - object to populate the version.
    
    Returns:
    znode content
    
    Throws:
    
    org.apache.zookeeper.KeeperException - if unexpected zookeeper exception
  - getDataNoWatch
```
public static byte[] getDataNoWatch(ZooKeeperWatcher zkw,
                    String pathOrRegionName,
                    org.apache.zookeeper.data.Stat stat)
                             throws org.apache.zookeeper.KeeperException
```
    Gets the current data in the unassigned node for the specified region name or fully-qualified path.
    Returns null if the region does not currently have a node.
    Does not set a watch.
    
    Parameters:
    zkw - zk reference
    pathOrRegionName - fully-specified path or region name
    stat - object to store node info into on getData call
    
    Returns:
    znode content
    
    Throws:
    
    org.apache.zookeeper.KeeperException - if unexpected zookeeper exception
  - getPath
```
public static String getPath(ZooKeeperWatcher zkw,
             String pathOrRegionName)
```
    Parameters:
    zkw -
    pathOrRegionName -
    
    Returns:
    Path to znode
  - getVersion
```
public static int getVersion(ZooKeeperWatcher zkw,
             HRegionInfo region)
                      throws org.apache.zookeeper.KeeperException
```
    Get the version of the specified znode
    
    Parameters:
    zkw - zk reference
    region - region's info
    
    Returns:
    the version of the znode, -1 if it doesn't exist
    
    Throws:
    
    org.apache.zookeeper.KeeperException
  - deleteNodeFailSilent
```
public static void deleteNodeFailSilent(ZooKeeperWatcher watcher,
                        HRegionInfo regionInfo)
                                 throws org.apache.zookeeper.KeeperException
```
    Delete the assignment node regardless of its current state.
    Fail silent even if the node does not exist at all.
    
    Parameters:
    watcher -
    regionInfo -
    
    Throws:
    
    org.apache.zookeeper.KeeperException
  - blockUntilNoRIT
```
public static void blockUntilNoRIT(ZooKeeperWatcher zkw)
                            throws org.apache.zookeeper.KeeperException,
                                   InterruptedException
```
    Blocks until there are no node in regions in transition.
    Used in testing only.
    
    Parameters:
    zkw - zk reference
    
    Throws:
    
    org.apache.zookeeper.KeeperException
    
    InterruptedException
  - blockUntilRIT
```
public static void blockUntilRIT(ZooKeeperWatcher zkw)
                          throws org.apache.zookeeper.KeeperException,
                                 InterruptedException
```
    Blocks until there is at least one node in regions in transition.
    Used in testing only.
    
    Parameters:
    zkw - zk reference
    
    Throws:
    
    org.apache.zookeeper.KeeperException
    
    InterruptedException
  - toString
```
static String toString(byte[] znodeBytes)
```
    Presume bytes are serialized unassigned data structure
    
    Parameters:
    znodeBytes -
    
    Returns:
    String of the deserialized znode bytes.

Class ZKAssign

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

LOG

Constructor Detail

ZKAssign

Method Detail

getNodeName

getRegionName

createNodeOffline

createNodeOffline

asyncCreateNodeOffline

createOrForceNodeOffline

deleteOpenedNode

deleteOfflineNode

deleteClosedNode

deleteClosingNode

deleteNode

deleteNode

deleteNode

deleteAllNodes

createNodeClosing

transitionNodeClosed

transitionNodeOpening

transitionNodeOpening

confirmNodeOpening

transitionNodeOpened

checkClosingState

transitionNode

transitionNode

getRegionTransition

getData

getDataAndWatch

getDataNoWatch

getPath

getVersion

deleteNodeFailSilent

blockUntilNoRIT

blockUntilRIT

toString