org.springframework.xd.shell.hadoop

Class ConfigurationAware

java.lang.Object

org.springframework.xd.shell.hadoop.ConfigurationAware

All Implemented Interfaces:

java.util.EventListener, org.springframework.context.ApplicationListener<ConfigurationModifiedEvent>, CommandMarker, ExecutionProcessor

Direct Known Subclasses:

FsShellCommands

public abstract class ConfigurationAware
extends java.lang.Object
implements org.springframework.context.ApplicationListener<ConfigurationModifiedEvent>, ExecutionProcessor

Utility base class for components monitoring Configuration changes in order to update state.

Author:

Costin Leau, Jarred Li

Field Summary

Fields

Modifier and Type	Field and Description
protected java.util.logging.Logger	LOG

Constructor Summary

Constructors

Constructor and Description
ConfigurationAware()

Method Summary

Methods

Modifier and Type	Method and Description
void	afterReturningInvocation(ParseResult invocationContext, java.lang.Object result)
void	afterThrowingInvocation(ParseResult invocationContext, java.lang.Throwable thrown)
ParseResult	beforeInvocation(ParseResult invocationContext)
protected abstract boolean	configurationChanged() Called before invoking a command in case the configuration changed.
protected java.lang.String	failedComponentName()
org.apache.hadoop.conf.Configuration	getHadoopConfiguration() Gets the hadoop configuration.
protected void	logUpdateError(java.lang.Exception ex)
void	onApplicationEvent(ConfigurationModifiedEvent event)

Methods inherited from class java.lang.Object

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

Field Detail

LOG

protected final java.util.logging.Logger LOG

Constructor Detail

ConfigurationAware

public ConfigurationAware()

Method Detail

onApplicationEvent

public void onApplicationEvent(ConfigurationModifiedEvent event)

Specified by:

onApplicationEvent in interface org.springframework.context.ApplicationListener<ConfigurationModifiedEvent>

beforeInvocation

public ParseResult beforeInvocation(ParseResult invocationContext)

Specified by:

beforeInvocation in interface ExecutionProcessor

configurationChanged

protected abstract boolean configurationChanged()
                                         throws java.lang.Exception

Called before invoking a command in case the configuration changed. Should return true if the change has been acknowledged, false otherwise. Implementation are encouraged to update their name accordingly through failedComponentName() to provide proper error messages.

Returns:

true if the change has been acknowledged, false otherwise.

Throws:

java.lang.Exception - ignored and causing the re-initialization to occur on the next call

See Also:

failedComponentName(), logUpdateError(Exception)

logUpdateError

protected void logUpdateError(java.lang.Exception ex)

failedComponentName

protected java.lang.String failedComponentName()

afterReturningInvocation

public void afterReturningInvocation(ParseResult invocationContext,
                            java.lang.Object result)

Specified by:

afterReturningInvocation in interface ExecutionProcessor

afterThrowingInvocation

public void afterThrowingInvocation(ParseResult invocationContext,
                           java.lang.Throwable thrown)

Specified by:

afterThrowingInvocation in interface ExecutionProcessor

getHadoopConfiguration

public org.apache.hadoop.conf.Configuration getHadoopConfiguration()

Gets the hadoop configuration.

Returns:

the hadoopConfiguration