org.datanucleus.store.rdbms.query

Class RDBMSQueryUtils

java.lang.Object

org.datanucleus.query.QueryUtils

org.datanucleus.store.rdbms.query.RDBMSQueryUtils

public class RDBMSQueryUtils
extends org.datanucleus.query.QueryUtils

Utilities for use in queries specific to RDBMS.

Constructor Summary

Constructors

Constructor and Description
RDBMSQueryUtils()

Method Summary

Modifier and Type	Method and Description
static String	getClassNameFromDiscriminatorResultSetRow(JavaTypeMapping discrimMapping, org.datanucleus.metadata.DiscriminatorMetaData dismd, ResultSet rs, org.datanucleus.ExecutionContext ec) Convenience method that takes a result set that contains a discriminator column and returns the class name that it represents.
static PreparedStatement	getPreparedStatementForQuery(org.datanucleus.store.connection.ManagedConnection conn, String queryStmt, org.datanucleus.store.query.Query query) Method to create a PreparedStatement for use with the query.
static ResultObjectFactory	getResultObjectFactoryForNoCandidateClass(RDBMSStoreManager storeMgr, ResultSet rs, Class resultClass) Utility to take a ResultSet and return a ResultObjectFactory for extracting the results, assuming that no candidate class is supplied.
static String	getResultSetConcurrencyForQuery(org.datanucleus.store.query.Query query) Accessor for the result set concurrency for the specified query.
static String	getResultSetTypeForQuery(org.datanucleus.store.query.Query query) Accessor for the result set type for the specified query.
static SQLStatement	getStatementForCandidates(RDBMSStoreManager storeMgr, SQLStatement parentStmt, org.datanucleus.metadata.AbstractClassMetaData cmd, StatementClassMapping clsMapping, org.datanucleus.ExecutionContext ec, Class candidateCls, boolean subclasses, String result, String candidateAlias, String candidateTableGroupName) Method to return a statement selecting the candidate table(s) required to cover all possible types for this candidates inheritance strategy.
static void	prepareStatementForExecution(PreparedStatement ps, org.datanucleus.store.query.Query query, boolean applyTimeout) Method to apply any restrictions to the created ResultSet.
static boolean	useUpdateLockForQuery(org.datanucleus.store.query.Query query) Convenience method to return if the specified query should use an "UPDATE" lock on returned objects.

Methods inherited from class org.datanucleus.query.QueryUtils

compareExpressionValues, createResultObjectUsingArgumentedConstructor, createResultObjectUsingDefaultConstructorAndSetters, createResultObjectUsingDefaultConstructorAndSetters, expressionHasNotOperator, expressionHasOrOperator, getExpressionsFromString, getKeyForQueryResultsCache, getParameterExpressionForPosition, getPublicPutMethodForResultClass, getPublicSetMethodForFieldOfResultClass, getStringValue, getStringValueForExpression, getValueForParameterExpression, orderCandidates, orderCandidates, orderCandidates, queryParameterTypesAreCompatible, queryReturnsSingleRow, resultClassIsSimple, resultClassIsUserType, resultHasOnlyAggregates

Methods inherited from class java.lang.Object

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

Constructor Detail

RDBMSQueryUtils

public RDBMSQueryUtils()

Method Detail

getClassNameFromDiscriminatorResultSetRow

public static String getClassNameFromDiscriminatorResultSetRow(JavaTypeMapping discrimMapping,
                                                               org.datanucleus.metadata.DiscriminatorMetaData dismd,
                                                               ResultSet rs,
                                                               org.datanucleus.ExecutionContext ec)

Convenience method that takes a result set that contains a discriminator column and returns the class name that it represents.

Parameters:

discrimMapping - Mapping for the discriminator column

dismd - Metadata for the discriminator

rs - The result set

ec - execution context

Returns:

The class name for the object represented in the current row

getResultSetTypeForQuery

public static String getResultSetTypeForQuery(org.datanucleus.store.query.Query query)

Accessor for the result set type for the specified query. Uses the persistence property "datanucleus.rdbms.query.resultSetType" and allows it to be overridden by the query extension of the same name. Checks both the PMF, and also the query extensions.

Parameters:

query - The query

Returns:

The result set type string

getResultSetConcurrencyForQuery

public static String getResultSetConcurrencyForQuery(org.datanucleus.store.query.Query query)

Accessor for the result set concurrency for the specified query. Uses the persistence property "datanucleus.rdbms.query.resultSetConcurrency" and allows it to be overridden by the query extension of the same name. Checks both the PMF, and also the query extensions.

Parameters:

query - The query

Returns:

The result set concurrency string

useUpdateLockForQuery

public static boolean useUpdateLockForQuery(org.datanucleus.store.query.Query query)

Convenience method to return if the specified query should use an "UPDATE" lock on returned objects. First checks whether serializeRead is set on the query and, if not, falls back to the setting for the class.

Parameters:

query - The query

Returns:

Whether to use an "UPDATE" lock

getPreparedStatementForQuery

public static PreparedStatement getPreparedStatementForQuery(org.datanucleus.store.connection.ManagedConnection conn,
                                                             String queryStmt,
                                                             org.datanucleus.store.query.Query query)
                                                      throws SQLException

Method to create a PreparedStatement for use with the query.

Parameters:

conn - the Connection

queryStmt - The statement text for the query

query - The query

Returns:

the PreparedStatement

Throws:

SQLException - Thrown if an error occurs creating the statement

prepareStatementForExecution

public static void prepareStatementForExecution(PreparedStatement ps,
                                                org.datanucleus.store.query.Query query,
                                                boolean applyTimeout)
                                         throws SQLException

Method to apply any restrictions to the created ResultSet.

Parameters:

ps - The PreparedStatement

query - The query

applyTimeout - Whether to apply the query timeout (if any) direct to the PreparedStatement

Throws:

SQLException - Thrown when an error occurs applying the constraints

getStatementForCandidates

public static SQLStatement getStatementForCandidates(RDBMSStoreManager storeMgr,
                                                     SQLStatement parentStmt,
                                                     org.datanucleus.metadata.AbstractClassMetaData cmd,
                                                     StatementClassMapping clsMapping,
                                                     org.datanucleus.ExecutionContext ec,
                                                     Class candidateCls,
                                                     boolean subclasses,
                                                     String result,
                                                     String candidateAlias,
                                                     String candidateTableGroupName)

Method to return a statement selecting the candidate table(s) required to cover all possible types for this candidates inheritance strategy.

Parameters:

storeMgr - RDBMS StoreManager

parentStmt - Parent statement (if there is one)

cmd - Metadata for the class

clsMapping - Mapping for the results of the statement

ec - ExecutionContext

candidateCls - Candidate class

subclasses - Whether to create a statement for subclasses of the candidate too

result - The result clause

candidateAlias - alias for the candidate (if any)

candidateTableGroupName - TableGroup name for the candidate (if any)

Returns:

The SQLStatement

Throws:

org.datanucleus.exceptions.NucleusException - if there are no tables for concrete classes in this query (hence would return null)

getResultObjectFactoryForNoCandidateClass

public static ResultObjectFactory getResultObjectFactoryForNoCandidateClass(RDBMSStoreManager storeMgr,
                                                                            ResultSet rs,
                                                                            Class resultClass)

Utility to take a ResultSet and return a ResultObjectFactory for extracting the results, assuming that no candidate class is supplied. The QueryResult will return either a result class type, or Object/Object[] depending on whether a ResultClass has been defined.

Parameters:

storeMgr - RDBMS StoreManager

rs - The ResultSet

resultClass - Result class if required (or null)

Returns:

The query ResultObjectFactory