org.apache.hadoop.hbase.constraint

Class Constraints

java.lang.Object

org.apache.hadoop.hbase.constraint.Constraints

@InterfaceAudience.Private
public final class Constraints
extends Object

Utilities for adding/removing constraints from a table.

Constraints can be added on table load time, via the HTableDescriptor.

NOTE: this class is NOT thread safe. Concurrent setting/enabling/disabling of constraints can cause constraints to be run at incorrect times or not at all.

Method Summary

Modifier and Type	Method and Description
static void	add(HTableDescriptor desc, Class<? extends Constraint>... constraints) Add configuration-less constraints to the table.
static void	add(HTableDescriptor desc, Class<? extends Constraint> constraint, Configuration conf) Add a Constraint to the table with the given configuration
static void	add(HTableDescriptor desc, Pair<Class<? extends Constraint>,Configuration>... constraints) Add constraints and their associated configurations to the table.
static void	disable(HTableDescriptor desc) Turn off processing constraints for a given table, even if constraints have been turned on or added.
static void	disableConstraint(HTableDescriptor desc, Class<? extends Constraint> clazz) Disable the given Constraint.
static void	enable(HTableDescriptor desc) Enable constraints on a table.
static void	enableConstraint(HTableDescriptor desc, Class<? extends Constraint> clazz) Enable the given Constraint.
static boolean	enabled(HTableDescriptor desc, Class<? extends Constraint> clazz) Check to see if the given constraint is enabled.
static boolean	has(HTableDescriptor desc, Class<? extends Constraint> clazz) Check to see if the Constraint is currently set.
static void	remove(HTableDescriptor desc) Remove all Constraints that have been added to the table and turn off the constraint processing.
static void	remove(HTableDescriptor desc, Class<? extends Constraint> clazz) Remove the constraint (and associated information) for the table descriptor.
static void	setConfiguration(HTableDescriptor desc, Class<? extends Constraint> clazz, Configuration configuration) Update the configuration for the Constraint; does not change the order in which the constraint is run.

Methods inherited from class java.lang.Object

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

Method Detail

enable

public static void enable(HTableDescriptor desc)
                   throws IOException

Enable constraints on a table.

Currently, if you attempt to add a constraint to the table, then Constraints will automatically be turned on.

Parameters:

desc - table description to add the processor

Throws:

IOException - If the ConstraintProcessor CP couldn't be added to the table.

disable

public static void disable(HTableDescriptor desc)

Turn off processing constraints for a given table, even if constraints have been turned on or added.

Parameters:

desc - HTableDescriptor where to disable Constraints.

remove

public static void remove(HTableDescriptor desc)

Remove all Constraints that have been added to the table and turn off the constraint processing.

All Configurations and their associated Constraint are removed.

Parameters:

desc - HTableDescriptor to remove Constraints from.

has

public static boolean has(HTableDescriptor desc,
                          Class<? extends Constraint> clazz)

Check to see if the Constraint is currently set.

Parameters:

desc - HTableDescriptor to check

clazz - Constraint class to check for.

Returns:

true if the Constraint is present, even if it is disabled. false otherwise.

add

public static void add(HTableDescriptor desc,
                       Class<? extends Constraint>... constraints)
                throws IOException

Add configuration-less constraints to the table.

This will overwrite any configuration associated with the previous constraint of the same class.

Each constraint, when added to the table, will have a specific priority, dictating the order in which the Constraint will be run. A Constraint earlier in the list will be run before those later in the list. The same logic applies between two Constraints over time (earlier added is run first on the regionserver).

Parameters:

desc - HTableDescriptor to add Constraints

constraints - Constraints to add. All constraints are considered automatically enabled on add

Throws:

IOException - If constraint could not be serialized/added to table

add

public static void add(HTableDescriptor desc,
                       Pair<Class<? extends Constraint>,Configuration>... constraints)
                throws IOException

Add constraints and their associated configurations to the table.

Adding the same constraint class twice will overwrite the first constraint's configuration

Each constraint, when added to the table, will have a specific priority, dictating the order in which the Constraint will be run. A Constraint earlier in the list will be run before those later in the list. The same logic applies between two Constraints over time (earlier added is run first on the regionserver).

Parameters:

desc - HTableDescriptor to add a Constraint

constraints - Pair of a Constraint and its associated Configuration. The Constraint will be configured on load with the specified configuration.All constraints are considered automatically enabled on add

Throws:

IOException - if any constraint could not be deserialized. Assumes if 1 constraint is not loaded properly, something has gone terribly wrong and that all constraints need to be enforced.

add

public static void add(HTableDescriptor desc,
                       Class<? extends Constraint> constraint,
                       Configuration conf)
                throws IOException

Add a Constraint to the table with the given configuration

Each constraint, when added to the table, will have a specific priority, dictating the order in which the Constraint will be run. A Constraint added will run on the regionserver before those added to the HTableDescriptor later.

Parameters:

desc - table descriptor to the constraint to

constraint - to be added

conf - configuration associated with the constraint

Throws:

IOException - if any constraint could not be deserialized. Assumes if 1 constraint is not loaded properly, something has gone terribly wrong and that all constraints need to be enforced.

setConfiguration

public static void setConfiguration(HTableDescriptor desc,
                                    Class<? extends Constraint> clazz,
                                    Configuration configuration)
                             throws IOException,
                                    IllegalArgumentException

Update the configuration for the Constraint; does not change the order in which the constraint is run.

Parameters:

desc - HTableDescriptor to update

clazz - Constraint to update

configuration - to update the Constraint with.

Throws:

IOException - if the Constraint was not stored correctly

IllegalArgumentException - if the Constraint was not present on this table.

remove

public static void remove(HTableDescriptor desc,
                          Class<? extends Constraint> clazz)

Remove the constraint (and associated information) for the table descriptor.

Parameters:

desc - HTableDescriptor to modify

clazz - Constraint class to remove

enableConstraint

public static void enableConstraint(HTableDescriptor desc,
                                    Class<? extends Constraint> clazz)
                             throws IOException

Enable the given Constraint. Retains all the information (e.g. Configuration) for the Constraint, but makes sure that it gets loaded on the table.

Parameters:

desc - HTableDescriptor to modify

clazz - Constraint to enable

Throws:

IOException - If the constraint cannot be properly deserialized

disableConstraint

public static void disableConstraint(HTableDescriptor desc,
                                     Class<? extends Constraint> clazz)
                              throws IOException

Disable the given Constraint. Retains all the information (e.g. Configuration) for the Constraint, but it just doesn't load the Constraint on the table.

Parameters:

desc - HTableDescriptor to modify

clazz - Constraint to disable.

Throws:

IOException - if the constraint cannot be found

enabled

public static boolean enabled(HTableDescriptor desc,
                              Class<? extends Constraint> clazz)
                       throws IOException

Check to see if the given constraint is enabled.

Parameters:

desc - HTableDescriptor to check.

clazz - Constraint to check for

Returns:

true if the Constraint is present and enabled. false otherwise.

Throws:

IOException - If the constraint has improperly stored in the table