com.sun.jdo.spi.persistence.support.sqlstore.sql.generator

Class SelectQueryPlan

java.lang.Object

com.sun.jdo.spi.persistence.support.sqlstore.sql.generator.QueryPlan

com.sun.jdo.spi.persistence.support.sqlstore.sql.generator.SelectQueryPlan

Direct Known Subclasses:

CorrelatedSelectPlan, VerificationSelectPlan

public class SelectQueryPlan
extends QueryPlan

This class prepares the generation of select statements, by joining the constaint stacks of all retrieve descriptors into one stack.

Field Summary

Fields

Modifier and Type	Field and Description
protected Constraint	constraint Pointer to the retrieve descriptor's constraint stack.
static String	MULTILEVEL_PREFETCH_PROPERTY Name of the MULTILEVEL_PREFETCH property.
int	options Bitmask constaining OPT_* Constants defined in RetrieveDescImpl
protected ForeignFieldDesc	parentField This foreign field joins this plan to the parent plan.
static int	ST_C_BUILT This plans's constraints are already processed.
static int	ST_OC_BUILT This plans's order by constraints are already processed.

Fields inherited from class com.sun.jdo.spi.persistence.support.sqlstore.sql.generator.QueryPlan

ACT_DELETE, ACT_INSERT, ACT_NOOP, ACT_SELECT, ACT_UPDATE, action, config, messages, ST_BUILT, statements, status, store, tables

Constructor Summary

Constructors

Constructor and Description
SelectQueryPlan(ActionDesc desc, SQLStoreManager store, Concurrency concurrency) Creates a new SelectQueryPlan.

Method Summary

Modifier and Type	Method and Description
protected void	addColumn(LocalFieldDesc fieldDesc) The addColumn method is used to specify a field for which data needs to be retrieved and therefore for which we need to select a column.
protected void	addJoinConstraint(SelectQueryPlan fromPlan, SelectQueryPlan toPlan, ArrayList fromColumns, ArrayList toColumns, int joinOp) Put in a join constraint to the foreign table.
protected void	addTable(LocalFieldDesc fieldDesc) The addTable method is used to add tables correponding to a field to the plan.
void	build() Builds the query plan for a select type ActionDesc (i.e.
Constraint	getConstraint()
Object	getResult(PersistenceManager pm, ResultSet resultData) Extract data from given resultData
static SelectQueryPlan	newInstance(RetrieveDescImpl desc, SQLStoreManager store, Concurrency concurrency) Creates a new instance of SelectQueryPlan depending on the retrieve descriptor options.
protected Statement	newStatement()
protected void	processConstraints()
protected void	processFields() Process the fields from the retrieve descriptor's field list.
void	processOrderConstraints() Converts ConstraintFieldName used in Order by constraints into ConstraintFieldDesc using ConstraintFieldName#originalPlan. Currently unused functionality: Gets all the "order by" constraints from the the current stack.
protected void	processStatements() This method goes through the statement list and tries to set up relationship between statements based on secondary table keys.

Methods inherited from class com.sun.jdo.spi.persistence.support.sqlstore.sql.generator.QueryPlan

addQueryTable, addQueryTable, addQueryTables, addStatement, createStatement, findQueryTable, findQueryTable, getAction, getConfig, getStatement, getStatements

Methods inherited from class java.lang.Object

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

Field Detail

ST_C_BUILT

public static final int ST_C_BUILT

This plans's constraints are already processed.

See Also:

Constant Field Values

ST_OC_BUILT

public static final int ST_OC_BUILT

This plans's order by constraints are already processed.

See Also:

Constant Field Values

constraint

protected Constraint constraint

Pointer to the retrieve descriptor's constraint stack. NOTE: The retrieve descriptor's stack will be modified building the query plan!

options

public int options

Bitmask constaining OPT_* Constants defined in RetrieveDescImpl

parentField

protected ForeignFieldDesc parentField

This foreign field joins this plan to the parent plan. The field is from config of the parent plan. Used only for dependent plan.

MULTILEVEL_PREFETCH_PROPERTY

public static final String MULTILEVEL_PREFETCH_PROPERTY

Name of the MULTILEVEL_PREFETCH property.

See Also:

Constant Field Values

Constructor Detail

SelectQueryPlan

public SelectQueryPlan(ActionDesc desc,
                       SQLStoreManager store,
                       Concurrency concurrency)

Creates a new SelectQueryPlan.

Parameters:

desc - Retrieve descriptor holding the query information from the query compiler. This information includes selected fields and the query constraints. desc must be an instance of RetrieveDescImpl.

store - Store manager executing the query.

concurrency - Query concurrency.

Method Detail

newInstance

public static SelectQueryPlan newInstance(RetrieveDescImpl desc,
                                          SQLStoreManager store,
                                          Concurrency concurrency)

Creates a new instance of SelectQueryPlan depending on the retrieve descriptor options.

Parameters:

desc - The retrieve descriptor

store - The store

concurrency - The concurrency for the plan.

Returns:

An instance of SelectQueryPlan depending on the retrieve descriptor options.

getConstraint

public Constraint getConstraint()

addTable

protected void addTable(LocalFieldDesc fieldDesc)

The addTable method is used to add tables correponding to a field to the plan. No columns corresponding the field are added to the plan.

Parameters:

fieldDesc - The field for which we need to add table

addColumn

protected void addColumn(LocalFieldDesc fieldDesc)

The addColumn method is used to specify a field for which data needs to be retrieved and therefore for which we need to select a column.

Parameters:

fieldDesc - The field for which we need to retrieve data and therefore for which we need to select a column.

processStatements

protected void processStatements()

Description copied from class: QueryPlan

This method goes through the statement list and tries to set up relationship between statements based on secondary table keys.

Overrides:

processStatements in class QueryPlan

build

public void build()

Builds the query plan for a select type ActionDesc (i.e. a RetrieveDesc).

Specified by:

build in class QueryPlan

processFields

protected void processFields()

Process the fields from the retrieve descriptor's field list. Must be overwritten by subquery plans!

processConstraints

protected void processConstraints()

addJoinConstraint

protected void addJoinConstraint(SelectQueryPlan fromPlan,
                                 SelectQueryPlan toPlan,
                                 ArrayList fromColumns,
                                 ArrayList toColumns,
                                 int joinOp)

Put in a join constraint to the foreign table.

Parameters:

fromPlan - The plan for fromColumns

toPlan - The plan for toColumns

fromColumns - List of local columns.

toColumns - List of foreign columns.

joinOp - Join operation. This operation is never a non relationship join.

processOrderConstraints

public void processOrderConstraints()

Converts ConstraintFieldName used in Order by constraints into ConstraintFieldDesc using ConstraintFieldName#originalPlan.
Currently unused functionality:
Gets all the "order by" constraints from the the current stack. The constraints are ordered such that any "order by" constraint with position N is placed before any "order by" constraint with position N+m, where m > 0. Also any "order by" constraint with no position (i.e. position < 0) are placed immediately following the previous "order by" constraint with a position. The order of the "order by" constraints on the constraint stack is changed to effect this ordering. NOTE: The value constraints giving the position for the order by constraints is currently not generated by the query compiler.

newStatement

protected Statement newStatement()

Specified by:

newStatement in class QueryPlan

getResult

public Object getResult(PersistenceManager pm,
                        ResultSet resultData)
                 throws SQLException

Extract data from given resultData

Parameters:

pm - The PersistenceManager.

resultData - The result set from which data is to be extracted.

Returns:

Result from the given resultData

Throws:

SQLException