org.kitesdk.data.spi

Class Constraints

java.lang.Object

org.kitesdk.data.spi.Constraints

@Immutable
public class Constraints
extends Object

A set of simultaneous constraints. This class accumulates combine manages a set of logical constraints.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	Constraints.KeyPredicate A Predicate for testing a StorageKey against a set of predicates.

Constructor Summary

Constructors

Constructor and Description
Constraints(Schema schema)
Constraints(Schema schema, PartitionStrategy strategy)

Method Summary

Methods

Modifier and Type	Method and Description
boolean	alignedWithBoundaries() If this returns true, the entities selected by this set of constraints align to partition boundaries.
boolean	equals(Object o)
<E> Iterator<E>	filter(Iterator<E> iterator, EntityAccessor<E> accessor) Filter the entities returned by a given iterator by these constraints.
Constraints	from(String name, Comparable value)
Constraints	fromAfter(String name, Comparable value)
static Constraints	fromQueryMap(Schema schema, PartitionStrategy strategy, Map<String,String> query)
Map<String,Object>	getProvidedValues() Returns a map of provided or fixed values for this constraint set.
int	hashCode()
boolean	isUnbounded() Returns true if there are no constraints.
Constraints	to(String name, Comparable value)
Constraints	toBefore(String name, Comparable value)
<E> com.google.common.base.Predicate<E>	toEntityPredicate(EntityAccessor<E> accessor) Get a Predicate for testing entity objects.
<E> com.google.common.base.Predicate<E>	toEntityPredicate(StorageKey key, EntityAccessor<E> accessor) Get a Predicate for testing entity objects that match the given StorageKey.
Constraints.KeyPredicate	toKeyPredicate() Get a Predicate that tests StorageKey objects.
Iterable<MarkerRange>	toKeyRanges() Get a set of MarkerRange objects that covers the set of possible StorageKey partitions for this constraint set.
Map<String,String>	toNormalizedQueryMap() Get a normalized query map for the constraints.
Map<String,String>	toQueryMap()
String	toString()
Constraints	with(String name, Object... values)

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Constructor Detail

Constraints

public Constraints(Schema schema)

Constraints

public Constraints(Schema schema,
           PartitionStrategy strategy)

Method Detail

toEntityPredicate

public <E> com.google.common.base.Predicate<E> toEntityPredicate(EntityAccessor<E> accessor)

Get a Predicate for testing entity objects.

Type Parameters:

E - The type of entities to be matched

Returns:

a Predicate to test if entity objects satisfy this constraint set

toEntityPredicate

public <E> com.google.common.base.Predicate<E> toEntityPredicate(StorageKey key,
                                                        EntityAccessor<E> accessor)

Get a Predicate for testing entity objects that match the given StorageKey.

Type Parameters:

E - The type of entities to be matched

Parameters:

key - a StorageKey for entities tested with the Predicate

Returns:

a Predicate to test if entity objects satisfy this constraint set

filter

public <E> Iterator<E> filter(Iterator<E> iterator,
                     EntityAccessor<E> accessor)

Filter the entities returned by a given iterator by these constraints.

Type Parameters:

E - The type of entities to be matched

Returns:

an iterator filtered by these constraints

toKeyPredicate

public Constraints.KeyPredicate toKeyPredicate()

Get a Predicate that tests StorageKey objects. If a StorageKey matches the predicate, it may represent a partition that is responsible for entities that match this set of constraints. If it does not match the predicate, it cannot be responsible for entities that match this constraint set.

Returns:

a Predicate for testing StorageKey objects

Throws:

NullPointerException - if no partition strategy is defined

toKeyRanges

public Iterable<MarkerRange> toKeyRanges()

Get a set of MarkerRange objects that covers the set of possible StorageKey partitions for this constraint set. If a StorageKey is not in one of the ranges returned by this method, then its partition cannot contain entities that satisfy this constraint set.

Returns:

an Iterable of MarkerRange

Throws:

NullPointerException - if no partition strategy is defined

alignedWithBoundaries

public boolean alignedWithBoundaries()

If this returns true, the entities selected by this set of constraints align to partition boundaries. For example, for a partition strategy [hash(num), identity(num)], any constraint on the "num" field will be correctly enforced by the partition predicate for this constraint set. However, a "color" field wouldn't be satisfied by considering partition values alone and would require further checks. An alternate explanation: This returns whether the key Predicate from toKeyPredicate() is equivalent to this set of constraints under the given PartitionStrategy. The key predicate must accept a key if that key's partition might include entities matched by this constraint set. If this method returns true, then all entities in the partitions it matches are guaranteed to match this constraint set. So, the partitions are equivalent to the constraints.

Returns:

true if this constraint set is satisfied by partitioning

Throws:

NullPointerException - if no partition strategy is defined

getProvidedValues

public Map<String,Object> getProvidedValues()

Returns a map of provided or fixed values for this constraint set. These values were accumulated by calls to with(String, Object).

Returns:

a Map of provided single values.

with

public Constraints with(String name,
               Object... values)

from

public Constraints from(String name,
               Comparable value)

fromAfter

public Constraints fromAfter(String name,
                    Comparable value)

to

public Constraints to(String name,
             Comparable value)

toBefore

public Constraints toBefore(String name,
                   Comparable value)

equals

public boolean equals(Object o)

Overrides:

equals in class Object

hashCode

public int hashCode()

Overrides:

hashCode in class Object

toString

public String toString()

Overrides:

toString in class Object

toQueryMap

public Map<String,String> toQueryMap()

toNormalizedQueryMap

public Map<String,String> toNormalizedQueryMap()

Get a normalized query map for the constraints. A normalized query map will be equal in value and iteration order for any logically equivalent set of constraints.

fromQueryMap

public static Constraints fromQueryMap(Schema schema,
                       PartitionStrategy strategy,
                       Map<String,String> query)

isUnbounded

public boolean isUnbounded()

Returns true if there are no constraints.

Returns:

true if there are no constraints, false otherwise