org.apache.lens.server.api.driver.hooks

Class ChainedDriverQueryHook

java.lang.Object

org.apache.lens.server.api.driver.hooks.NoOpDriverQueryHook

org.apache.lens.server.api.driver.hooks.ChainedDriverQueryHook

All Implemented Interfaces:

DriverQueryHook

public class ChainedDriverQueryHook
extends NoOpDriverQueryHook

This hook allows chaining of different hooks. A driver can specify multiple hooks for itself by providing `query.hook.classes` in its configuration. The value should be a comma separated list of class names, each of which should be an implementation of org.apache.lens.server.api.driver.hooks.DriverQueryHook. This hook stores instances of those classes. All the methods of this class invokes the same method on each of the hooks in the chain.

Constructor Summary

Constructors

Constructor and Description
ChainedDriverQueryHook(Iterable<DriverQueryHook> hooks)

Method Summary

Modifier and Type	Method and Description
boolean	equals(Object o)
static ChainedDriverQueryHook	from(org.apache.hadoop.conf.Configuration conf, String key)
Iterable<DriverQueryHook>	getHooks()
int	hashCode()
void	postDriverSelection(AbstractQueryContext ctx) Called just after driver has been selected to execute a query.
void	postEstimate(AbstractQueryContext ctx) Called just after a successful estimate operation is tried on this driver
void	postRewrite(AbstractQueryContext ctx) Called just after a successful rewrite operation is tried on this driver
void	preEstimate(AbstractQueryContext ctx) Called just before estimate operation is tried on this driver Note : Estimate operation will be skipped if rewrite operation fails for this driver
void	preLaunch(QueryContext ctx) Called just before launching the query on the selected driver.
void	preRewrite(AbstractQueryContext ctx) Called just before rewrite operation is tried on this driver
void	setDriver(LensDriver driver) This setter method is called by the driver once hook instance is created.
String	toString()

Methods inherited from class org.apache.lens.server.api.driver.hooks.NoOpDriverQueryHook

getDriver

Methods inherited from class java.lang.Object

getClass, notify, notifyAll, wait, wait, wait

Constructor Detail

ChainedDriverQueryHook

@ConstructorProperties(value="hooks")
 @Generated(value="lombok")
public ChainedDriverQueryHook(Iterable<DriverQueryHook> hooks)

Method Detail

setDriver

public void setDriver(LensDriver driver)

Description copied from interface: DriverQueryHook

This setter method is called by the driver once hook instance is created. This driver information can be used while extracting driver specific information form the QueryContext.

Specified by:

setDriver in interface DriverQueryHook

Overrides:

setDriver in class NoOpDriverQueryHook

preRewrite

public void preRewrite(AbstractQueryContext ctx)
                throws LensException

Description copied from interface: DriverQueryHook

Called just before rewrite operation is tried on this driver

Specified by:

preRewrite in interface DriverQueryHook

Overrides:

preRewrite in class NoOpDriverQueryHook

Throws:

LensException

postRewrite

public void postRewrite(AbstractQueryContext ctx)
                 throws LensException

Description copied from interface: DriverQueryHook

Called just after a successful rewrite operation is tried on this driver

Specified by:

postRewrite in interface DriverQueryHook

Overrides:

postRewrite in class NoOpDriverQueryHook

Throws:

LensException

preEstimate

public void preEstimate(AbstractQueryContext ctx)
                 throws LensException

Description copied from interface: DriverQueryHook

Called just before estimate operation is tried on this driver Note : Estimate operation will be skipped if rewrite operation fails for this driver

Specified by:

preEstimate in interface DriverQueryHook

Overrides:

preEstimate in class NoOpDriverQueryHook

Throws:

LensException

postEstimate

public void postEstimate(AbstractQueryContext ctx)
                  throws LensException

Description copied from interface: DriverQueryHook

Called just after a successful estimate operation is tried on this driver

Specified by:

postEstimate in interface DriverQueryHook

Overrides:

postEstimate in class NoOpDriverQueryHook

Throws:

LensException

postDriverSelection

public void postDriverSelection(AbstractQueryContext ctx)
                         throws LensException

Description copied from interface: DriverQueryHook

Called just after driver has been selected to execute a query.

Specified by:

postDriverSelection in interface DriverQueryHook

Overrides:

postDriverSelection in class NoOpDriverQueryHook

Throws:

LensException

preLaunch

public void preLaunch(QueryContext ctx)
               throws LensException

Description copied from interface: DriverQueryHook

Called just before launching the query on the selected driver.

Specified by:

preLaunch in interface DriverQueryHook

Overrides:

preLaunch in class NoOpDriverQueryHook

Throws:

LensException

from

public static ChainedDriverQueryHook from(org.apache.hadoop.conf.Configuration conf,
                                          String key)
                                   throws LensException

Throws:

LensException

getHooks

@Generated(value="lombok")
public Iterable<DriverQueryHook> getHooks()

equals

@Generated(value="lombok")
public boolean equals(Object o)

Overrides:

equals in class Object

hashCode

@Generated(value="lombok")
public int hashCode()

Overrides:

hashCode in class Object

toString

@Generated(value="lombok")
public String toString()

Overrides:

toString in class Object