类 org.apache.hadoop.hdfs.server.protocol.DatanodeCommand
的使用

使用DatanodeCommand的程序包

程序包	说明
org.apache.hadoop.hdfs.server.namenode
org.apache.hadoop.hdfs.server.protocol

org.apache.hadoop.hdfs.server.namenode中DatanodeCommand的使用

返回DatanodeCommand的org.apache.hadoop.hdfs.server.namenode中的方法

限定符和类型	方法和说明
DatanodeCommand	NameNode.blockReport(DatanodeRegistration nodeReg, long[] blocks)
DatanodeCommand[]	NameNode.sendHeartbeat(DatanodeRegistration nodeReg, long capacity, long dfsUsed, long remaining, int xmitsInProgress, int xceiverCount) Data node notify the name node that it is alive Return an array of block-oriented commands for the datanode to execute.

org.apache.hadoop.hdfs.server.protocol中DatanodeCommand的使用

org.apache.hadoop.hdfs.server.protocol中DatanodeCommand的子类

限定符和类型	类和说明
class	BalancerBandwidthCommand Balancer bandwidth command instructs each datanode to change its value for the max amount of network bandwidth it may use during the block balancing operation.
class	BlockCommand A BlockCommand is an instruction to a datanode regarding some blocks under its control.
class	KeyUpdateCommand
class	UpgradeCommand This as a generic distributed upgrade command.

声明为DatanodeCommand的org.apache.hadoop.hdfs.server.protocol中的字段

限定符和类型	字段和说明
static DatanodeCommand	DatanodeCommand.FINALIZE
static DatanodeCommand	DatanodeCommand.REGISTER

返回DatanodeCommand的org.apache.hadoop.hdfs.server.protocol中的方法

限定符和类型	方法和说明
DatanodeCommand	DatanodeProtocol.blockReport(DatanodeRegistration registration, long[] blocks) blockReport() tells the NameNode about all the locally-stored blocks.
DatanodeCommand[]	DatanodeProtocol.sendHeartbeat(DatanodeRegistration registration, long capacity, long dfsUsed, long remaining, int xmitsInProgress, int xceiverCount) sendHeartbeat() tells the NameNode that the DataNode is still alive and well.