com.gemstone.gemfire.cache.query
Interface QueryService

public interface QueryService

Interface for the query service, which is used for instantiating queries, creating and destroying indexes, creating CQs and operating on CQs. The CQs work on the server regions, the client can use the CQ methods supported in this class to create/operate CQs on the server. The CQ obtains the Server connection from the corresponding local region on the client. The implementation of this interface is obtained from the Cache using Cache.getQueryService().

Since:

4.0

Field Summary

static com.gemstone.gemfire.cache.query.internal.Undefined

UNDEFINED The undefined constant

Method Summary

void	closeCqs() Unregister all Continuous Queries.
Index	createIndex(String indexName, IndexType indexType, String indexedExpression, String fromClause) Create an index that can be used when executing queries.
Index	createIndex(String indexName, IndexType indexType, String indexedExpression, String fromClause, String imports) Create an index that can be used when executing queries.
void	executeCqs() Starts execution of all the registered continuous queries for this client.
void	executeCqs(String regionName) Starts execution of all the continuous queries registered on the specified region for this client.
CqQuery	getCq(String cqName) Retrieves the Continuous Query specified by the name.
CqQuery[]	getCqs() Retrieve all registered Continuous Queries.
CqQuery[]	getCqs(String regionName) Retrieves all the registered Continuous Queries for a given region.
CqServiceStatistics	getCqStatistics() Returns CqServiceStatistics object, which provides helper methods to get CQ service related statistics for this client.
Index	getIndex(Region region, String indexName) Get the Index from the specified Region with the specified name.
Collection	getIndexes() Get a collection of all the indexes in the Cache.
Collection	getIndexes(Region region) Get a collection of all the indexes on the specified Region
Collection	getIndexes(Region region, IndexType indexType) Get a collection of all the indexes on the specified Region of the specified index type.
CqQuery	newCq(String queryString, CqAttributes cqAttr) Constructs a new continuous query, represented by an instance of CqQuery.
CqQuery	newCq(String queryString, CqAttributes cqAttr, boolean isDurable) Constructs a new continuous query, represented by an instance of CqQuery.
CqQuery	newCq(String name, String queryString, CqAttributes cqAttr) Constructs a new named continuous query, represented by an instance of CqQuery.
CqQuery	newCq(String name, String queryString, CqAttributes cqAttr, boolean isDurable) Constructs a new named continuous query, represented by an instance of CqQuery.
Query	newQuery(String queryString) Constructs a new Query object.
void	removeIndex(Index index) Remove the specified index.
void	removeIndexes() Remove all the indexes from this cache.
void	removeIndexes(Region region) Remove all the indexes on the specified Region
void	stopCqs() Stops execution of all the continuous queries for this client to become inactive.
void	stopCqs(String regionName) Stops execution of all the continuous queries registered on the specified region for this client.

Field Detail

UNDEFINED

static final com.gemstone.gemfire.cache.query.internal.Undefined UNDEFINED

The undefined constant

Method Detail

newQuery

Query newQuery(String queryString)

Constructs a new Query object.

Parameters:

queryString - the String that is the query program

Returns:

The new Query object.

Throws:

QueryInvalidException - if the syntax of the queryString is invalid.

See Also:

Query

createIndex

Index createIndex(String indexName,
                  IndexType indexType,
                  String indexedExpression,
                  String fromClause)
                  throws IndexInvalidException,
                         IndexNameConflictException,
                         IndexExistsException,
                         RegionNotFoundException,
                         UnsupportedOperationException

Create an index that can be used when executing queries.

Parameters:

indexName - the name of this index, used for statistics collection and to identify this index for later access

indexType - the type of index

indexedExpression - the expression to index on, a function dependent on region entries individually; must not contain query parameters (e.g. $1).

fromClause - expression that evaluates to the collection(s) that will be queried over, must contain one and only one region path, must not contain query parameters. For primary key indexes, the fromClause must be just one collection which must be a region path only.

Returns:

the newly created Index

Throws:

QueryInvalidException - if the argument query lanaguage strings have invalid syntax

IndexInvalidException - if the arguments do not correctly specify an index

IndexNameConflictException - if an index with this name already exists

IndexExistsException - if an index with these parameters already exists with a different name

RegionNotFoundException - if the region referred to in the fromClause doesn't exist

UnsupportedOperationException - If Index is being created on a region which overflows to disk

createIndex

Index createIndex(String indexName,
                  IndexType indexType,
                  String indexedExpression,
                  String fromClause,
                  String imports)
                  throws IndexInvalidException,
                         IndexNameConflictException,
                         IndexExistsException,
                         RegionNotFoundException,
                         UnsupportedOperationException

Create an index that can be used when executing queries.

Parameters:

indexName - the name of this index, used for statistics collection and to identify this index for later access

indexType - the type of index

indexedExpression - the expression to index on, a function dependent on region entries individually; must not contain query parameters (e.g. $1).

fromClause - expression that evaluates to the collection(s) that will be queried over, must contain one and only one region path, must not contain query parameters. For primary key indexes, the fromClause must be just one collection which must be a region path only.

imports - string containing imports (in the query language syntax, each import statement separated by a semicolon), providing an import context for the indexedExpression and the fromClause.

Returns:

the newly created Index

Throws:

QueryInvalidException - if the argument query language strings have invalid syntax

IndexInvalidException - if the arguments do not correctly specify an index

IndexNameConflictException - if an index with this name already exists

IndexExistsException - if an index with these parameters already exists with a different name

RegionNotFoundException - if the region referred to in the fromClause doesn't exist

UnsupportedOperationException - If Index is being created on a region which overflows to disk

getIndex

Index getIndex(Region region,
               String indexName)

Get the Index from the specified Region with the specified name.

Parameters:

region - the Region for the requested index

Returns:

the index of the region with this name, or null if there isn't one

getIndexes

Collection getIndexes()

Get a collection of all the indexes in the Cache.

Returns:

the collection of all indexes in this Cache

getIndexes

Collection getIndexes(Region region)

Get a collection of all the indexes on the specified Region

Parameters:

region - the region for the requested indexes

Returns:

the collection of indexes on the specified region

getIndexes

Collection getIndexes(Region region,
                      IndexType indexType)

Get a collection of all the indexes on the specified Region of the specified index type.

Parameters:

region - the region for the requested indexes

indexType - the type of indexes to get. Currently must be Indexable.FUNCTIONAL

Returns:

the collection of indexes for the specified region and type

removeIndex

void removeIndex(Index index)

Remove the specified index.

Parameters:

index - the Index to remove

removeIndexes

void removeIndexes()

Remove all the indexes from this cache.

removeIndexes

void removeIndexes(Region region)

Remove all the indexes on the specified Region

Parameters:

region - the Region to remove all indexes from

newCq

CqQuery newCq(String queryString,
              CqAttributes cqAttr)
              throws QueryInvalidException,
                     CqException,
                     CqInvalidException

Constructs a new continuous query, represented by an instance of CqQuery. The CqQuery is not executed until the execute method is invoked on the CqQuery.

Parameters:

queryString - the OQL query

cqAttr - the CqAttributes

Returns:

the newly created CqQuery object

Throws:

IllegalArgumentException - if queryString or cqAttr is null.

IllegalStateException - if this method is called from a cache server.

QueryInvalidException - if there is a syntax error in the query.

CqException - if failed to create CQ.

CqInvalidException - if the query does not meet the CQ constraints. E.g.: Query string should refer to only one region. Joins are not supported. The query must be a SELECT statement. DISTINCT queries are not supported. Projections are not supported. Only one iterator in the FROM clause is supported, and it must be a region path. Bind parameters in the query are not yet supported.

newCq

CqQuery newCq(String queryString,
              CqAttributes cqAttr,
              boolean isDurable)
              throws QueryInvalidException,
                     CqException,
                     CqInvalidException

Constructs a new continuous query, represented by an instance of CqQuery. The CqQuery is not executed until the execute method is invoked on the CqQuery.

Parameters:

queryString - the OQL query

cqAttr - the CqAttributes

isDurable - true if the CQ is durable

Returns:

the newly created CqQuery object

Throws:

IllegalArgumentException - if queryString or cqAttr is null.

IllegalStateException - if this method is called from a cache server.

QueryInvalidException - if there is a syntax error in the query.

CqException - if failed to create CQ.

CqInvalidException - if the query does not meet the CQ constraints. E.g.: Query string should refer to only one region. Joins are not supported. The query must be a SELECT statement. DISTINCT queries are not supported. Projections are not supported. Only one iterator in the FROM clause is supported, and it must be a region path. Bind parameters in the query are not yet supported.

newCq

CqQuery newCq(String name,
              String queryString,
              CqAttributes cqAttr)
              throws QueryInvalidException,
                     CqExistsException,
                     CqException,
                     CqInvalidException

Constructs a new named continuous query, represented by an instance of CqQuery. The CqQuery is not executed until the execute method is invoked on the CqQuery. The name of the query will be used to identify this query in statistics archival.

Parameters:

name - the String name for this query

queryString - the OQL query

cqAttr - the CqAttributes

Returns:

the newly created CqQuery object

Throws:

CqExistsException - if a CQ by this name already exists on this client

IllegalArgumentException - if queryString or cqAttr is null.

IllegalStateException - if this method is called from a cache server.

QueryInvalidException - if there is a syntax error in the query.

CqException - if failed to create cq.

CqInvalidException - if the query does not meet the CQ constraints. E.g.: Query string should refer to only one region. Joins are not supported. The query must be a SELECT statement. DISTINCT queries are not supported. Projections are not supported. Only one iterator in the FROM clause is supported, and it must be a region path. Bind parameters in the query are not yet supported.

newCq

CqQuery newCq(String name,
              String queryString,
              CqAttributes cqAttr,
              boolean isDurable)
              throws QueryInvalidException,
                     CqExistsException,
                     CqException,
                     CqInvalidException

Constructs a new named continuous query, represented by an instance of CqQuery. The CqQuery is not executed until the execute method is invoked on the CqQuery. The name of the query will be used to identify this query in statistics archival.

Parameters:

name - the String name for this query

queryString - the OQL query

cqAttr - the CqAttributes

isDurable - true if the CQ is durable

Returns:

the newly created CqQuery object

Throws:

CqExistsException - if a CQ by this name already exists on this client

IllegalArgumentException - if queryString or cqAttr is null.

IllegalStateException - if this method is called from a cache server.

QueryInvalidException - if there is a syntax error in the query.

CqException - if failed to create cq.

CqInvalidException - if the query does not meet the CQ constraints. E.g.: Query string should refer to only one region. Joins are not supported. The query must be a SELECT statement. DISTINCT queries are not supported. Projections are not supported. Only one iterator in the FROM clause is supported, and it must be a region path. Bind parameters in the query are not yet supported.

closeCqs

void closeCqs()

Unregister all Continuous Queries. All artifacts and resources associated with the CQs are released. Any attempt to access closed CqQuery objects will result in the CqClosedException being thrown to the caller.

getCqs

CqQuery[] getCqs()

Retrieve all registered Continuous Queries. This is a collection of CqQuery objects.

Returns:

CqQuery[] list of registered CQs, null if there are no CQs.

getCqs

CqQuery[] getCqs(String regionName)
                 throws CqException

Retrieves all the registered Continuous Queries for a given region. This is a collection of CqQuery objects.

Returns:

CqQuery[] list of registered CQs on the specified region, null if there are no CQs.

Throws:

CqException - if the region does not exist.

getCq

CqQuery getCq(String cqName)

Retrieves the Continuous Query specified by the name.

Parameters:

cqName - - String, name of the CQ

Returns:

CqQuery object, null if no CqQuery object is found.

executeCqs

void executeCqs()
                throws CqException

Starts execution of all the registered continuous queries for this client. This is complementary to stopCqs.

Throws:

CqException - if failure to execute CQ.

See Also:

stopCqs()

stopCqs

void stopCqs()
             throws CqException

Stops execution of all the continuous queries for this client to become inactive. This is useful when client needs to control the incoming CQ messages during bulk region operations.

Throws:

CqException - if failure to execute CQ.

See Also:

executeCqs()

executeCqs

void executeCqs(String regionName)
                throws CqException

Starts execution of all the continuous queries registered on the specified region for this client. This is complementary method to stopCQs().

Throws:

CqException - if failure to stop CQs.

See Also:

stopCqs()

stopCqs

void stopCqs(String regionName)
             throws CqException

Stops execution of all the continuous queries registered on the specified region for this client. This is useful when client needs to control the incoming CQ messages during bulk region operations.

Throws:

CqException - if failure to execute CQs.

See Also:

executeCqs()

getCqStatistics

CqServiceStatistics getCqStatistics()

Returns CqServiceStatistics object, which provides helper methods to get CQ service related statistics for this client. Specifically the following aggregate information on the client's CQs is collected: Number of CQs created (cumulative) Number of CQs active currently Number of CQs stopped or suspended currently Number of CQs closed (cumulative) Number of CQs active on a specified region currently

Returns:

CqServiceStatistics

See Also:

CqServiceStatistics