net.sf.basedb.core
Class AbstractHqlQuery

java.lang.Object
  net.sf.basedb.core.AbstractQuery
      net.sf.basedb.core.AbstractHqlQuery

All Implemented Interfaces:

HqlQuery, Query

Direct Known Subclasses:

AbstractEntityQuery, SpecialQuery

abstract class AbstractHqlQuery
extends AbstractQuery
implements HqlQuery

An abstract implementation of the HqlQuery interface. The class can be used to build and manage just about any type of HQL query. It has no function for executing the query or returning the result. Subclasses may use getMainHqlQuery(DbControl) to generate a Hibernate Query object that is ready to be executed.

Version:

2.15

Author:

Nicklas

Last modified

$Date: 2011-02-04 09:25:16 +0100 (Fri, 04 Feb 2011) $

Field Summary

private boolean	cacheResults If the results should be cached or not.
private static boolean	debugEnabled So we don't always have to call logParam.debug()
private DbControl	lastCountDc The most recent DbControl used to build/execute the count query.
private Query	lastCountQuery The most recent count query.
private DbControl	lastMainDc The most recent DbControl used to build/execute the main query.
private Query	lastMainQuery The most recent main query.
private static Logger	logParam Log all parameter bindings to prepared statement.
private String	rootAlias The alias for the root table.
private boolean	stateless If the query should be executed in a stateless session or not.
private static Set<Integer>	ZERO_SET

Constructor Summary

AbstractHqlQuery(String root, String alias, boolean stateless)
Create a new HQL query.

Method Summary

long	count(DbControl dc) Count the number of items/rows that are returned by the query.
(package private) Query	getCountHqlQuery(DbControl dc) Build the count query and set parameter values for it.
(package private) Query	getMainHqlQuery(DbControl dc) Build the main query and set parameter values for it.
QueryType	getQueryType() Get the type of query.
String	getRootAlias() The alias of the item that is the root of this query.
boolean	isCachingResult() If the query results are cached or not.
boolean	isReadonly() If this query is readonly and cannot be structurally modified.
protected boolean	isStateless() If queries are using the stateless Hibernate session or the regular session.
protected String	postProcessQuery(String query) Processes the query so that joined paths that are found in other parts of the query are replaced with the join alias.
private String	replaceWithJoinAliases(String query) Replaces parts of the query with joined aliases.
void	reset() Reset all non-permanent query elements of the query and clear cached queries.
void	setCacheResult(boolean flag) Specify if the query results should be cached or not.
void	setEntityParameter(String name, BasicItem value) Set the value of an entity parameter.
private void	setParameters(Query query, Map<String,QueryParameter> parameters) Set parameter values on a query.
void	setPermanentEntityParameter(String name, BasicItem value) Permanently set the value of an entity parameter.

Methods inherited from class net.sf.basedb.core.AbstractQuery

addAutoJoiner, getCountQuery, getFirstResult, getMainQuery, getMaxResults, getParameterNames, getParameters, getParameterType, getParameterValue, getPermanentSelects, getQueryParameter, getQuerySection, getSelects, group, groupPermanent, hasParameterValue, having, havingPermanent, isCounting, isDistinct, isFailSafe, isReturningTotalCount, join, joinPermanent, order, orderPermanent, resetTemporary, restrict, restrictPermanent, select, selectPermanent, setCounting, setDistinct, setFailSafe, setFirstResult, setMaxResults, setParameter, setPermanentParameter, setReturnTotalCount, temporaryJoin, temporarySelect, toQl, toString

Methods inherited from class java.lang.Object

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

Methods inherited from interface net.sf.basedb.core.query.Query

addAutoJoiner, getFirstResult, getMaxResults, getParameterNames, getQueryParameter, getQuerySection, group, groupPermanent, hasParameterValue, having, havingPermanent, isCounting, isDistinct, isFailSafe, isReturningTotalCount, join, joinPermanent, order, orderPermanent, restrict, restrictPermanent, select, selectPermanent, setDistinct, setFailSafe, setFirstResult, setMaxResults, setParameter, setPermanentParameter, setReturnTotalCount, toQl

Field Detail

logParam

private static final Logger logParam

Log all parameter bindings to prepared statement.

debugEnabled

private static final boolean debugEnabled

So we don't always have to call logParam.debug()

rootAlias

private final String rootAlias

The alias for the root table. This is a requirement in HQL that is not needed in SQL. SELECT ... FROM [rootTable] as [rootAlias]

stateless

private final boolean stateless

If the query should be executed in a stateless session or not.

lastMainDc

private DbControl lastMainDc

The most recent DbControl used to build/execute the main query.

lastCountDc

private DbControl lastCountDc

The most recent DbControl used to build/execute the count query.

lastMainQuery

private Query lastMainQuery

The most recent main query.

lastCountQuery

private Query lastCountQuery

The most recent count query.

cacheResults

private boolean cacheResults

If the results should be cached or not.

ZERO_SET

private static final Set<Integer> ZERO_SET

Constructor Detail

AbstractHqlQuery

AbstractHqlQuery(String root,
                 String alias,
                 boolean stateless)

Create a new HQL query. The root table and alias must be given.

Method Detail

getQueryType

public QueryType getQueryType()

Description copied from interface: Query

Get the type of query. Ie. The query language.

Specified by:

getQueryType in interface Query

Returns:

QueryType.HQL

getRootAlias

public String getRootAlias()

The alias of the item that is the root of this query.

Specified by:

getRootAlias in interface Query

See Also:

Item.getAlias()

isReadonly

public boolean isReadonly()

Description copied from interface: Query

If this query is readonly and cannot be structurally modified. Ie. no more query elements can be added. It is still possible to set parameter values. A call to Query.reset() would unlock the query and allow it to be modified again.

Specified by:

isReadonly in interface Query

Overrides:

isReadonly in class AbstractQuery

Returns:

TRUE if the query is readonly, FALSE otherwise

reset

public void reset()

Reset all non-permanent query elements of the query and clear cached queries.

Specified by:

reset in interface Query

Overrides:

reset in class AbstractQuery

count

public long count(DbControl dc)
           throws BaseException

Description copied from interface: Query

Count the number of items/rows that are returned by the query. The method ignores the Query.getFirstResult() and Query.getMaxResults() settings.

Specified by:

count in interface Query

Returns:

The number of rows/items returned by the query

Throws:

BaseException - If there is an error

setCacheResult

public void setCacheResult(boolean flag)

Description copied from interface: HqlQuery

Specify if the query results should be cached or not.

Specified by:

setCacheResult in interface HqlQuery

Parameters:

flag - TRUE if the query results should be cached, FALSE otherwise

isCachingResult

public boolean isCachingResult()

Description copied from interface: HqlQuery

If the query results are cached or not.

Specified by:

isCachingResult in interface HqlQuery

See Also:

HqlQuery.setCacheResult(boolean)

setEntityParameter

public void setEntityParameter(String name,
                               BasicItem value)

Description copied from interface: HqlQuery

Set the value of an entity parameter. If the value of this parameter has already been set permanently, an InvalidDataException is thrown.

Specified by:

setEntityParameter in interface HqlQuery

Parameters:

name - The name of the parameter

value - The value of the parameter

setPermanentEntityParameter

public void setPermanentEntityParameter(String name,
                                        BasicItem value)

Description copied from interface: HqlQuery

Permanently set the value of an entity parameter. If the value of this parameter has already been set permanently, an InvalidDataException is thrown.

Specified by:

setPermanentEntityParameter in interface HqlQuery

Parameters:

name - The name of the parameter

value - The value of the parameter

getMainHqlQuery

Query getMainHqlQuery(DbControl dc)

Build the main query and set parameter values for it. If the query has been executed with the same DbControl before and hasn't been reset() the cached query is returned. If the parameters values have been changed the new values are used.

Parameters:

dc - The DbControl to use for executing the query

Returns:

A org.hibernate.Query object

getCountHqlQuery

Query getCountHqlQuery(DbControl dc)

Build the count query and set parameter values for it. If the query has been executed with the same DbControl before and hasn't been reset() the cached query is returned. If the parameters values have been changed the new values are used.

Parameters:

dc - The DbControl to use for executing the query

Returns:

A org.hibernate.Query object

isStateless

protected boolean isStateless()

If queries are using the stateless Hibernate session or the regular session.

Returns:

TRUE if the stateless session is used, FALSE otherwise

postProcessQuery

protected String postProcessQuery(String query)

Processes the query so that joined paths that are found in other parts of the query are replaced with the join alias.

Overrides:

postProcessQuery in class AbstractQuery

replaceWithJoinAliases

private String replaceWithJoinAliases(String query)

Replaces parts of the query with joined aliases. This is needed for Hibernate to generate correct SQL. Eg. select f from Foo f join f.bar b where f.bar.name = :name needs to be changed to: select f from Foo f join f.bar b where b.name = :name

We implement this by looking for the joined path and replacing it with the joined alias.

For left fetch joins we also need to make sure that no more than one step is joined at a time since the implicit join created by Hibernate is not a fetch join.

setParameters

private void setParameters(Query query,
                           Map<String,QueryParameter> parameters)

Set parameter values on a query.

Parameters:

query - The Hibernate query object

parameters - A map containing parameter names and values