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.

Field Summary

Fields

Modifier and Type	Field and Description
private static Pattern	CONSTRAINT_HTD_ATTR_KEY_PATTERN
private static String	CONSTRAINT_HTD_KEY_PREFIX
private static Comparator<Constraint>	constraintComparator
private static String	COUNTER_KEY
private static int	DEFAULT_PRIORITY
private static String	ENABLED_KEY
private static org.slf4j.Logger	LOG
private static long	MIN_PRIORITY
private static String	PRIORITY_KEY
private static long	UNSET_PRIORITY

Constructor Summary

Constructors

Modifier	Constructor and Description
private	Constraints()

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, org.apache.hadoop.conf.Configuration conf) Add a Constraint to the table with the given configuration
static void	add(HTableDescriptor desc, Pair<Class<? extends Constraint>,org.apache.hadoop.conf.Configuration>... constraints) Add constraints and their associated configurations to the table.
private static void	addConstraint(HTableDescriptor desc, Class<? extends Constraint> clazz, org.apache.hadoop.conf.Configuration conf, long priority) Write the raw constraint and configuration to the descriptor.
private static void	changeConstraintEnabled(HTableDescriptor desc, Class<? extends Constraint> clazz, boolean enabled) Change the whether the constraint (if it is already present) is enabled or disabled.
private static org.apache.hadoop.conf.Configuration	configure(org.apache.hadoop.conf.Configuration conf, boolean enabled, long priority) Setup the configuration for a constraint as to whether it is enabled and its priority
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.
(package private) static List<? extends Constraint>	getConstraints(TableDescriptor desc, ClassLoader classloader) Get the constraints stored in the table descriptor
private static Pair<String,String>	getKeyValueForClass(HTableDescriptor desc, Class<? extends Constraint> clazz) Get the kv Map.Entry in the descriptor for the specified class
private static long	getNextPriority(HTableDescriptor desc)
static boolean	has(HTableDescriptor desc, Class<? extends Constraint> clazz) Check to see if the Constraint is currently set.
private static org.apache.hadoop.conf.Configuration	readConfiguration(byte[] bytes) Read the Configuration stored in the byte stream.
private static org.apache.hadoop.conf.Configuration	readConfiguration(String bytes) Read in the configuration from the String encoded configuration
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.
private static String	serializeConfiguration(org.apache.hadoop.conf.Configuration conf) Write the configuration to a String
private static String	serializeConstraintClass(Class<? extends Constraint> clazz) Just write the class to a String representation of the class as a key for the HTableDescriptor
static void	setConfiguration(HTableDescriptor desc, Class<? extends Constraint> clazz, org.apache.hadoop.conf.Configuration configuration) Update the configuration for the Constraint; does not change the order in which the constraint is run.
private static void	updateLatestPriority(HTableDescriptor desc, long priority)
private static void	writeConstraint(HTableDescriptor desc, String key, org.apache.hadoop.conf.Configuration conf) Write the given key and associated configuration to the HTableDescriptor

Methods inherited from class java.lang.Object

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

Field Detail

DEFAULT_PRIORITY

private static final int DEFAULT_PRIORITY

See Also:

Constant Field Values

LOG

private static final org.slf4j.Logger LOG

CONSTRAINT_HTD_KEY_PREFIX

private static final String CONSTRAINT_HTD_KEY_PREFIX

See Also:

Constant Field Values

CONSTRAINT_HTD_ATTR_KEY_PATTERN

private static final Pattern CONSTRAINT_HTD_ATTR_KEY_PATTERN

ENABLED_KEY

private static final String ENABLED_KEY

See Also:

Constant Field Values

PRIORITY_KEY

private static final String PRIORITY_KEY

See Also:

Constant Field Values

MIN_PRIORITY

private static final long MIN_PRIORITY

See Also:

Constant Field Values

UNSET_PRIORITY

private static final long UNSET_PRIORITY

See Also:

Constant Field Values

COUNTER_KEY

private static String COUNTER_KEY

constraintComparator

private static final Comparator<Constraint> constraintComparator

Constructor Detail

Constraints

private Constraints()

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.

getKeyValueForClass

private static Pair<String,String> getKeyValueForClass(HTableDescriptor desc,
                                                       Class<? extends Constraint> clazz)

Get the kv Map.Entry in the descriptor for the specified class

Parameters:

desc - HTableDescriptor to read

clazz - To search for

Returns:

The Pair of <key, value> in the table, if that class is present. NULL 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>,org.apache.hadoop.conf.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,
                       org.apache.hadoop.conf.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.

addConstraint

private static void addConstraint(HTableDescriptor desc,
                                  Class<? extends Constraint> clazz,
                                  org.apache.hadoop.conf.Configuration conf,
                                  long priority)
                           throws IOException

Write the raw constraint and configuration to the descriptor.

This method takes care of creating a new configuration based on the passed in configuration and then updating that with enabled and priority of the constraint.

When a constraint is added, it is automatically enabled.

Throws:

IOException

configure

private static org.apache.hadoop.conf.Configuration configure(org.apache.hadoop.conf.Configuration conf,
                                                              boolean enabled,
                                                              long priority)

Setup the configuration for a constraint as to whether it is enabled and its priority

Parameters:

conf - on which to base the new configuration

enabled - true if it should be run

priority - relative to other constraints

Returns:

a new configuration, storable in the HTableDescriptor

serializeConstraintClass

private static String serializeConstraintClass(Class<? extends Constraint> clazz)

Just write the class to a String representation of the class as a key for the HTableDescriptor

Parameters:

clazz - Constraint class to convert to a HTableDescriptor key

Returns:

key to store in the HTableDescriptor

writeConstraint

private static void writeConstraint(HTableDescriptor desc,
                                    String key,
                                    org.apache.hadoop.conf.Configuration conf)
                             throws IOException

Write the given key and associated configuration to the HTableDescriptor

Throws:

IOException

serializeConfiguration

private static String serializeConfiguration(org.apache.hadoop.conf.Configuration conf)
                                      throws IOException

Write the configuration to a String

Parameters:

conf - to write

Returns:

String representation of that configuration

Throws:

IOException

readConfiguration

private static org.apache.hadoop.conf.Configuration readConfiguration(byte[] bytes)
                                                               throws IOException

Read the Configuration stored in the byte stream.

Parameters:

bytes - to read from

Returns:

A valid configuration

Throws:

IOException

readConfiguration

private static org.apache.hadoop.conf.Configuration readConfiguration(String bytes)
                                                               throws IOException

Read in the configuration from the String encoded configuration

Parameters:

bytes - to read from

Returns:

A valid configuration

Throws:

IOException - if the configuration could not be read

getNextPriority

private static long getNextPriority(HTableDescriptor desc)

updateLatestPriority

private static void updateLatestPriority(HTableDescriptor desc,
                                         long priority)

setConfiguration

public static void setConfiguration(HTableDescriptor desc,
                                    Class<? extends Constraint> clazz,
                                    org.apache.hadoop.conf.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

changeConstraintEnabled

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

Change the whether the constraint (if it is already present) is enabled or disabled.

Throws:

IOException

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

getConstraints

static List<? extends Constraint> getConstraints(TableDescriptor desc,
                                                 ClassLoader classloader)
                                          throws IOException

Get the constraints stored in the table descriptor

Parameters:

desc - To read from

classloader - To use when loading classes. If a special classloader is used on a region, for instance, then that should be the classloader used to load the constraints. This could also apply to unit-testing situation, where want to ensure that class is reloaded or not.

Returns:

List of configured Constraints

Throws:

IOException - if any part of reading/arguments fails