co.cask.cdap.data2.transaction.queue

Class QueueEntryRow

java.lang.Object

co.cask.cdap.data2.transaction.queue.QueueEntryRow

public class QueueEntryRow
extends Object

Holds logic of how queue entry row is constructed

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	QueueEntryRow.CanConsume Defines if queue entry can be consumed

Field Summary

Fields

Modifier and Type	Field and Description
static byte[]	COLUMN_FAMILY
static byte[]	DATA_COLUMN
static byte[]	META_COLUMN
static byte[]	STATE_COLUMN_PREFIX

Constructor Summary

Constructors

Constructor and Description
QueueEntryRow()

Method Summary

Methods

Modifier and Type	Method and Description
static QueueEntryRow.CanConsume	canConsume(ConsumerConfig consumerConfig, co.cask.tephra.Transaction transaction, long enqueueWritePointer, int counter, byte[] metaValue, byte[] stateValue) Looks at specific queue entry and determines if consumer with given consumer config and current transaction can consume this entry.
static int	getHashConsumerInstance(Map<String,Integer> hashes, String key, int groupSize)
static byte[]	getQueueEntryRowKey(QueueName queueName, long writePoint, int count) Simple method to return a queue entry row key.
static QueueName	getQueueName(String namespaceId, String appName, String flowName, int prefixBytes, byte[] rowBuffer, int rowOffset, int rowLength) Extracts the queue name from the KeyValue row, which the row must be a queue entry.
static byte[]	getQueueRowPrefix(QueueName queueName) Returns a byte array representing prefix of a queue.
static int	getRoundRobinConsumerInstance(long writePointer, int counter, int groupSize) Returns the consumer instance id for consuming an entry enqueued with the given write pointer and counter.
static ConsumerEntryState	getState(byte[] stateValue)
static int	getStateInstanceId(byte[] stateValue)
static long	getStateWritePointer(byte[] stateValue)
static byte[]	getStopRowForTransaction(byte[] queueRowPrefix, co.cask.tephra.Transaction transaction) Gets the stop row for scan up to the read pointer of a transaction.
static long	getWritePointer(byte[] rowKey, int queueRowPrefixLength) Gets the write pointer for a row.
static boolean	isCommittedProcessed(byte[] stateBytes, co.cask.tephra.Transaction tx) For a queue entry consumer state, serialized to byte array, return whether it is processed and committed.
static boolean	isDataColumn(byte[] qualifierBuffer, int qualifierOffset) Returns true if the given byte[] is a data column qualifier in queue entry row.
static boolean	isDataColumn(org.apache.hadoop.hbase.KeyValue keyValue) Returns true if the given KeyValue is a data column in queue entry row.
static boolean	isMetaColumn(byte[] qualifierBuffer, int qualifierOffset) Returns true if the given byte[] is a meta column qualifier in queue entry row.
static boolean	isMetaColumn(org.apache.hadoop.hbase.KeyValue keyValue) Returns true if the given KeyValue is a meta column in queue entry row.
static boolean	isQueueEntry(byte[] queueRowPrefix, int prefixBytes, byte[] rowBuffer, int rowOffset, int rowLength) Returns true if the given row is a queue entry of the given queue based on queue row prefix
static boolean	isStateColumn(byte[] columnName) Determine whether a column represent the state of a consumer.
static boolean	isStateColumn(byte[] qualifierBuffer, int qualifierOffset) Returns true if the given byte[] is a state column qualifier in queue entry row.
static boolean	isStateColumn(org.apache.hadoop.hbase.KeyValue keyValue) Returns true if the given KeyValue is a state column in queue entry row.

Methods inherited from class java.lang.Object

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

Field Detail

COLUMN_FAMILY

public static final byte[] COLUMN_FAMILY

DATA_COLUMN

public static final byte[] DATA_COLUMN

META_COLUMN

public static final byte[] META_COLUMN

STATE_COLUMN_PREFIX

public static final byte[] STATE_COLUMN_PREFIX

Constructor Detail

QueueEntryRow

public QueueEntryRow()

Method Detail

getQueueRowPrefix

public static byte[] getQueueRowPrefix(QueueName queueName)

Returns a byte array representing prefix of a queue. The prefix is formed by first byte of MD5 of the queue name followed by the queue name.

getQueueEntryRowKey

public static byte[] getQueueEntryRowKey(QueueName queueName,
                         long writePoint,
                         int count)

Simple method to return a queue entry row key. This method is not for performance usage (e.g. in enqueue).

isStateColumn

public static boolean isStateColumn(byte[] columnName)

Determine whether a column represent the state of a consumer.

getStateWritePointer

public static long getStateWritePointer(byte[] stateValue)

Parameters:

stateValue - value of the state column

Returns:

write pointer of the latest change of the state value

getStateInstanceId

public static int getStateInstanceId(byte[] stateValue)

Parameters:

stateValue - value of the state column

Returns:

state instance id

getState

public static ConsumerEntryState getState(byte[] stateValue)

Parameters:

stateValue - value of the state column

Returns:

consumer entry state

getQueueName

public static QueueName getQueueName(String namespaceId,
                     String appName,
                     String flowName,
                     int prefixBytes,
                     byte[] rowBuffer,
                     int rowOffset,
                     int rowLength)

Extracts the queue name from the KeyValue row, which the row must be a queue entry.

isQueueEntry

public static boolean isQueueEntry(byte[] queueRowPrefix,
                   int prefixBytes,
                   byte[] rowBuffer,
                   int rowOffset,
                   int rowLength)

Returns true if the given row is a queue entry of the given queue based on queue row prefix

isStateColumn

public static boolean isStateColumn(org.apache.hadoop.hbase.KeyValue keyValue)

Returns true if the given KeyValue is a state column in queue entry row.

isStateColumn

public static boolean isStateColumn(byte[] qualifierBuffer,
                    int qualifierOffset)

Returns true if the given byte[] is a state column qualifier in queue entry row.

isMetaColumn

public static boolean isMetaColumn(org.apache.hadoop.hbase.KeyValue keyValue)

Returns true if the given KeyValue is a meta column in queue entry row.

isMetaColumn

public static boolean isMetaColumn(byte[] qualifierBuffer,
                   int qualifierOffset)

Returns true if the given byte[] is a meta column qualifier in queue entry row.

isDataColumn

public static boolean isDataColumn(org.apache.hadoop.hbase.KeyValue keyValue)

Returns true if the given KeyValue is a data column in queue entry row.

isDataColumn

public static boolean isDataColumn(byte[] qualifierBuffer,
                   int qualifierOffset)

Returns true if the given byte[] is a data column qualifier in queue entry row.

canConsume

public static QueueEntryRow.CanConsume canConsume(ConsumerConfig consumerConfig,
                                  co.cask.tephra.Transaction transaction,
                                  long enqueueWritePointer,
                                  int counter,
                                  byte[] metaValue,
                                  byte[] stateValue)

Looks at specific queue entry and determines if consumer with given consumer config and current transaction can consume this entry. The answer can be "yes" (QueueEntryRow.CanConsume.YES, "no" (QueueEntryRow.CanConsume.NO, "no" with a hint that given consumer cannot consume any of the entries prior to this one (QueueEntryRow.CanConsume.NO_INCLUDING_ALL_OLDER. The latter one allows for some optimizations when doing scans of entries to be consumed.

Parameters:

consumerConfig - config of the consumer

transaction - current tx

enqueueWritePointer - write pointer used by enqueue of this entry

counter - counter of this entry

metaValue - value of meta column of this entry

stateValue - value of state column of this entry

Returns:

one QueueEntryRow.CanConsume as per description above.

getRoundRobinConsumerInstance

public static int getRoundRobinConsumerInstance(long writePointer,
                                int counter,
                                int groupSize)

Returns the consumer instance id for consuming an entry enqueued with the given write pointer and counter.

getHashConsumerInstance

public static int getHashConsumerInstance(Map<String,Integer> hashes,
                          String key,
                          int groupSize)

getStopRowForTransaction

public static byte[] getStopRowForTransaction(byte[] queueRowPrefix,
                              co.cask.tephra.Transaction transaction)

Gets the stop row for scan up to the read pointer of a transaction. Stop row is queueName + (readPointer + 1).

isCommittedProcessed

public static boolean isCommittedProcessed(byte[] stateBytes,
                           co.cask.tephra.Transaction tx)

For a queue entry consumer state, serialized to byte array, return whether it is processed and committed.

getWritePointer

public static long getWritePointer(byte[] rowKey,
                   int queueRowPrefixLength)

Gets the write pointer for a row.