BalanceProcedure (Apache Hadoop Federation Balance 3.4.1.200-dep-1000 API)

java.lang.Object
- org.apache.hadoop.tools.fedbalance.procedure.BalanceProcedure<T>

All Implemented Interfaces:

org.apache.hadoop.io.Writable

Direct Known Subclasses:

DistCpProcedure, TrashProcedure
```
public abstract class BalanceProcedure<T extends BalanceProcedure>
extends java.lang.Object
implements org.apache.hadoop.io.Writable
```
The basic components of the Job. Extend this class to implement different job logic.

Nested Class Summary

Nested Classes
Modifier and Type Class Description

static class BalanceProcedure.RetryException
The RetryException represents the current procedure should be delayed then retried.

Nested Classes
Modifier and Type	Class	Description
`static class`	`BalanceProcedure.RetryException`	The RetryException represents the current procedure should be delayed then retried.

Field Summary

Fields
Modifier and Type Field Description

static org.slf4j.Logger LOG

Fields
Modifier and Type	Field	Description
`static org.slf4j.Logger`	`LOG`

Constructor Summary

Constructors
Constructor	Description
`BalanceProcedure()`
`BalanceProcedure(java.lang.String name, long delayDuration)`
`BalanceProcedure(java.lang.String name, java.lang.String nextProcedure, long delayDuration)`	The constructor of BalanceProcedure.

Method Summary

All Methods Instance Methods Abstract Methods Concrete Methods
Modifier and Type	Method	Description
`long`	`delayMillisBeforeRetry()`	The time in milliseconds the procedure should wait before retry.
`boolean`	`equals(java.lang.Object obj)`
`abstract boolean`	`execute()`	The main process.
`int`	`hashCode()`
`protected boolean`	`isSchedulerShutdown()`	The active flag.
`java.lang.String`	`name()`	Get the procedure name.
`java.lang.String`	`nextProcedure()`	Get the next procedure.
`void`	`readFields(java.io.DataInput in)`
`protected void`	`setNextProcedure(java.lang.String nextProcedure)`
`java.lang.String`	`toString()`
`void`	`write(java.io.DataOutput out)`

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

- Field Detail
  - LOG
```
public static final org.slf4j.Logger LOG
```
- Constructor Detail
  - BalanceProcedure
```
public BalanceProcedure()
```
  - BalanceProcedure
```
public BalanceProcedure(java.lang.String name,
                        java.lang.String nextProcedure,
                        long delayDuration)
```
    The constructor of BalanceProcedure.
    
    Parameters:
    
    name - the name of the procedure.
    
    nextProcedure - the name of the next procedure.
    
    delayDuration - the delay duration when this procedure is delayed.
  - BalanceProcedure
```
public BalanceProcedure(java.lang.String name,
                        long delayDuration)
```
- Method Detail
  - execute
```
public abstract boolean execute()
                         throws BalanceProcedure.RetryException,
                                java.io.IOException
```
    The main process. This is called by the ProcedureScheduler. Make sure the process quits fast when it's interrupted and the scheduler is shut down. One procedure may have many phases and all the phases share the same member variables. Each time this method returns, the journal is saved. User can serialize the current phase in write(DataOutput) so the job can continue with the last unfinished phase after it is recovered. The return value indicates whether the job should go to the next procedure. Return true after all the phases finish. Example: class ProcedureWithManyPhase extends BalanceProcedure { enum PHASE { P1, P2, P3 } PHASE phase; public boolean execute(T lastProcedure) throws RetryException, IOException { switch (phase) { case P1: // do something. return false; case P2: // do something. return false; case P3: // do something. return true; default: throw new IOException("Unexpected phase " + phase); } } public void write(DataOutput out) { out.writeInt(phase.ordinal()); } public void readFields(DataInput in) throws IOException { stage = Stage.values()[in.readInt()]; } }
    
    Returns:
    
    true if the procedure has done and the job will go to the next procedure, otherwise false.
    
    Throws:
    
    BalanceProcedure.RetryException - if this procedure needs delay a while then retry.
    
    java.io.IOException
  - delayMillisBeforeRetry
```
public long delayMillisBeforeRetry()
```
    The time in milliseconds the procedure should wait before retry.
  - isSchedulerShutdown
```
protected boolean isSchedulerShutdown()
```
    The active flag.
  - setNextProcedure
```
protected void setNextProcedure(java.lang.String nextProcedure)
```
  - nextProcedure
```
public java.lang.String nextProcedure()
```
    Get the next procedure.
  - name
```
public java.lang.String name()
```
    Get the procedure name.
  - write
```
public void write(java.io.DataOutput out)
           throws java.io.IOException
```
    Specified by:
    
    write in interface org.apache.hadoop.io.Writable
    
    Throws:
    
    java.io.IOException
  - readFields
```
public void readFields(java.io.DataInput in)
                throws java.io.IOException
```
    Specified by:
    
    readFields in interface org.apache.hadoop.io.Writable
    
    Throws:
    
    java.io.IOException
  - hashCode
```
public int hashCode()
```
    Overrides:
    
    hashCode in class java.lang.Object
  - equals
```
public boolean equals(java.lang.Object obj)
```
    Overrides:
    
    equals in class java.lang.Object
  - toString
```
public java.lang.String toString()
```
    Overrides:
    
    toString in class java.lang.Object

Class BalanceProcedure<T extends BalanceProcedure>

Nested Class Summary

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

LOG

Constructor Detail

BalanceProcedure

BalanceProcedure

BalanceProcedure

Method Detail

execute

delayMillisBeforeRetry

isSchedulerShutdown

setNextProcedure

nextProcedure

name

write

readFields

hashCode

equals

toString