com.hazelcast.query.impl

Interface Index

All Known Subinterfaces:

InternalIndex

All Known Implementing Classes:

AbstractIndex, IndexImpl

public interface Index

Represents an index built on top of the attribute of the map entries.

Nested Class Summary

Nested Classes

Modifier and Type	Interface and Description
static class	Index.OperationSource Identifies an original source of an index operation.

Method Summary

Modifier and Type	Method and Description
boolean	canEvaluate(Class<? extends Predicate> predicateClass)
void	clear() Clears out all entries from this index.
void	destroy() Releases all resources hold by this index, e.g.
Set<QueryableEntry>	evaluate(Predicate predicate) Evaluates the given predicate using this index.
String[]	getComponents()
TypeConverter	getConverter()
String	getName()
Set<QueryableEntry>	getRecords(Comparable value) Produces a result set containing entries whose attribute values are equal to the given value.
Set<QueryableEntry>	getRecords(Comparable[] values) Produces a result set containing entries whose attribute values are equal to at least one of the given values.
Set<QueryableEntry>	getRecords(Comparable from, boolean fromInclusive, Comparable to, boolean toInclusive) Produces a result set by performing a range query on this index with the range defined by the passed arguments.
Set<QueryableEntry>	getRecords(Comparison comparison, Comparable value) Produces a result set containing entries whose attribute values are satisfy the comparison of the given type with the given value.
String	getUniqueKey()
boolean	isEvaluateOnly()
boolean	isOrdered() Tells whether this index is ordered or not.
void	putEntry(QueryableEntry entry, Object oldValue, Index.OperationSource operationSource) Saves the given entry into this index.
void	removeEntry(Data key, Object value, Index.OperationSource operationSource) Removes the entry having the given key and the value from this index.

Method Detail

getName

String getName()

Returns:

the canonical name of this index: for single-attribute non-composite indexes, it's an attribute name itself stripping an unnecessary "this." qualifier and replacing "#" qualifier with ".", if any; for composite indexes, it's a comma-separated list of canonicalized index component attribute names with a single space character going after every comma.

See Also:

PredicateUtils.canonicalizeAttribute(java.lang.String), PredicateUtils.constructCanonicalCompositeIndexName(java.lang.String[])

getComponents

String[] getComponents()

Returns:

the components of this index.

isOrdered

boolean isOrdered()

Tells whether this index is ordered or not.

Ordered indexes support the fast evaluation of range queries. Unordered indexes are still capable to execute range queries, but the performance would be about the same as the full scan performance.

Returns:

true if this index is ordered, false otherwise.

See Also:

getRecords(Comparison, Comparable), getRecords(Comparable, boolean, Comparable, boolean)

getUniqueKey

String getUniqueKey()

Returns:

the unique key attribute for bitmap indexes, null if this index is not a bitmap one.

getConverter

TypeConverter getConverter()

Returns:

the converter associated with this index; or null if the converter is not known because there were no saves to this index and the attribute type is not inferred yet.

putEntry

void putEntry(QueryableEntry entry,
              Object oldValue,
              Index.OperationSource operationSource)

Saves the given entry into this index.

Parameters:

entry - the entry to save.

oldValue - the previous old value associated with the entry or null if the entry is new.

operationSource - the operation source.

Throws:

QueryException - if there were errors while extracting the attribute value from the entry.

removeEntry

void removeEntry(Data key,
                 Object value,
                 Index.OperationSource operationSource)

Removes the entry having the given key and the value from this index.

Parameters:

key - the key of the entry to remove.

value - the value of the entry to remove.

operationSource - the operation source.

Throws:

QueryException - if there were errors while extracting the attribute value from the entry.

isEvaluateOnly

boolean isEvaluateOnly()

Returns:

true if this index supports querying only with evaluate(com.hazelcast.query.Predicate) method, false otherwise.

canEvaluate

boolean canEvaluate(Class<? extends Predicate> predicateClass)

Returns:

true if this index can evaluate a predicate of the given predicate class, false otherwise.

evaluate

Set<QueryableEntry> evaluate(Predicate predicate)

Evaluates the given predicate using this index.

Parameters:

predicate - the predicate to evaluate. The predicate is guaranteed to be evaluable by this index (canEvaluate returned true for its class).

Returns:

a set containing entries matching the given predicate.

getRecords

Set<QueryableEntry> getRecords(Comparable value)

Produces a result set containing entries whose attribute values are equal to the given value.

Parameters:

value - the value to compare against.

Returns:

the produced result set.

getRecords

Set<QueryableEntry> getRecords(Comparable[] values)

Produces a result set containing entries whose attribute values are equal to at least one of the given values.

Parameters:

values - the values to compare against.

Returns:

the produced result set.

getRecords

Set<QueryableEntry> getRecords(Comparable from,
                               boolean fromInclusive,
                               Comparable to,
                               boolean toInclusive)

Produces a result set by performing a range query on this index with the range defined by the passed arguments.

Parameters:

from - the beginning of the range.

fromInclusive - true if the beginning of the range is inclusive, false otherwise.

to - the end of the range.

toInclusive - true if the end of the range is inclusive, false otherwise.

Returns:

the produced result set.

getRecords

Set<QueryableEntry> getRecords(Comparison comparison,
                               Comparable value)

Produces a result set containing entries whose attribute values are satisfy the comparison of the given type with the given value.

Parameters:

comparison - the type of the comparison to perform.

value - the value to compare against.

Returns:

the produced result set.

clear

void clear()

Clears out all entries from this index.

destroy

void destroy()

Releases all resources hold by this index, e.g. the allocated native memory for the HD index.