ch.elca.el4j.services.persistence.jpa.criteria
Class QueryBuilder

java.lang.Object
  ch.elca.el4j.services.persistence.jpa.criteria.QueryBuilder

All Implemented Interfaces:

CountQuery, Expression, SelectQuery

public final class QueryBuilder
extends Object
implements Expression, SelectQuery, CountQuery

SQL Query Builder. TODO: adapt the following example such that it produces valid JPQL. (no ON clause, but AS instead)

Example query definition:

      QueryBuilder builder = QueryBuilder.select("dep.NAME", "emp.name");
      QueryBuilder subQueryBuilder = QueryBuilder.select("1");
      subQueryBuilder.from("Dual ").startAnd().ifNotNull("1 <> {p}", 2).end().endBuilder();

      builder.from("DEPARTMENT dep")
          .innerJoin("EMPLOYEE emp", "dep.ID = emp.DEPARTMENT_ID")
          .innerJoin("UNIVERSITY unv", "unv.ID = dep.UNV_ID")
      .startOr()
          .ifNotNull("emp.position = {p}", "pos")
          .startAnd()
              .ifNotNull("emp.SALARY > {p}", 200)
              .ifNotNull("emp.SALARY < {p}", 300)
          .end()
          .exist(subQueryBuilder)
          .ifNotNull("dep.ID in {p}", depIds)
      .end()
      .orderBy(SortOrder.ASC, "dep.ID").endBuilder();
 

The above query is equivalent to the following SQL:

     SELECT dep.NAME, emp.NAME
     FROM DEPARTMENT dep
         JOIN emp ON (dep.ID = emp.DEPARTMENT_ID)
         JOIN UNIVERSITY unv ON (unv.ID = dep.UNV_ID)
     WHERE emp.POSITION = {p}
         OR (emp.SALARY > {p} AND emp.SALARY < {p})" 
         OR EXISTS (SELECT 1 FROM DUAL WHERE 1 <> {p})
     ORDER BY DEP.ID ASC";
 

Author:

Simon Stelling (SST), Huy Hung Nguyen (HUN)

File-location:

QueryBuilder

Last check-in date:

2010-12-21 11:08:04 +0100 (Di, 21. Dez 2010) by swismer for revision 4253

Nested Class Summary

class

QueryBuilder.ConditionList<T extends Expression> Condition of QueryBuilder.

Method Summary

QueryBuilder	addSelectParameter(Object... parameters) TODO: what's this?
void	append(String query) TODO: this seems wrong. what's this for?
CountQuery	applyCount(javax.persistence.EntityManager entityManager) creates count query with the given EntityManager and stores the prepared query which is then executed through the getCount() method.
SelectQuery	applySelect(javax.persistence.EntityManager entityManager) creates select query with the given EntityManager and stores the prepared query which is then executed through the getResultList() methods.
SelectQuery	applySelect(javax.persistence.EntityManager entityManager, Class<?> resultClass) creates select query with the given EntityManager and stores the prepared query which is then executed through the getResultList() methods.
QueryBuilder	clearOrderBy() drops all ordering constraints.
QueryBuilder	endBuilder() Mark this query as completed.
QueryBuilder	from(Class<?>... entityClasses) Specifies on which classes the query is based.
QueryBuilder	from(String... from) Specifies on which tables the query is based.
QueryBuilder	fromIf(String fromExp, boolean cond) same as from(String...) except that from clause is added iff condition evaluates to true.
List<Object>	getBodyParameters() Get all attached parameters.
int	getCount()
List<?>	getRawResultList()
<T> List<T>	getResultList(Class<T> clazz) returns all entities matching the query.
<T> List<T>	getResultList(Class<T> clazz, int firstRow, int maxNumOfRows) gets at most maxNumOfRows results, first one being firstRow.
List<?>	getResultList(int firstRow, int maxNumOfRows) returns the results in the given range.
List<Object>	getSelectParameters() get SelectParameters.
<T> T	getSingleResult(Class<T> clazz)
QueryBuilder	innerJoin(String join, String on) Only used for native sql.
QueryBuilder	innerJoin(String join, String on, Object... params) Only used for native sql.
QueryBuilder	join(String join) Dont need 'on', used for JPQL.
QueryBuilder	joinIf(String join, boolean cond) Dont need 'on', used for JPQL.
QueryBuilder	joinIf(String join, String on, boolean cond, Object... params) like joinIf(String, String, boolean, Object...) but join is performed iff cond evaluates to true.
QueryBuilder	leftJoin(String join, String on)
QueryBuilder	leftJoin(String join, String on, Object... params) Only used for native sql.
QueryBuilder	orderBy(SortOrder sortOrder, String orderBy) appends the given column to the ordering restrictions iff not already ordered by the given column.
QueryBuilder	orderByIf(SortOrder sortOrder, String orderBy, boolean cond) Appends given column to the ordering restrictions iff cond evaluates to true.
QueryBuilder	rightJoin(String join, String on)
QueryBuilder	rightJoin(String join, String on, Object... params) Only used for native sql.
static QueryBuilder	select(String... select) Creates a new Query with the given SELECT clause.
void	setParameters(List<Object> parameters) Set parameters of the query.
QueryBuilder.ConditionList<QueryBuilder>	startAnd() marks the beginning of a list of predicates to be ANDed.
QueryBuilder.ConditionList<QueryBuilder>	startOr() marks the beginning of a list of predicates to be ORed.
String	toString()
QueryBuilder	union(QueryBuilder builder)

Methods inherited from class java.lang.Object

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

Method Detail

getSelectParameters

public List<Object> getSelectParameters()

get SelectParameters.

Returns:

the selectParameters

select

public static QueryBuilder select(String... select)

Creates a new Query with the given SELECT clause.

Parameters:

select - select clause

Returns:

a new query

addSelectParameter

public QueryBuilder addSelectParameter(Object... parameters)

TODO: what's this?

from

public QueryBuilder from(Class<?>... entityClasses)

Specifies on which classes the query is based.

Parameters:

entityClasses - entities' classes

Returns:

this

from

public QueryBuilder from(String... from)

Specifies on which tables the query is based.

Parameters:

from - tables

Returns:

this

fromIf

public QueryBuilder fromIf(String fromExp,
                           boolean cond)

same as from(String...) except that from clause is added iff condition evaluates to true.

Parameters:

fromExp - from string to add

cond - predicate

Returns:

this

innerJoin

public QueryBuilder innerJoin(String join,
                              String on,
                              Object... params)

Only used for native sql.

Parameters:

join -

on -

params -

Returns:

innerJoin

public QueryBuilder innerJoin(String join,
                              String on)

Only used for native sql.

Parameters:

join -

on -

params -

Returns:

leftJoin

public QueryBuilder leftJoin(String join,
                             String on,
                             Object... params)

Only used for native sql.

Parameters:

join -

on -

params -

Returns:

leftJoin

public QueryBuilder leftJoin(String join,
                             String on)

union

public QueryBuilder union(QueryBuilder builder)

rightJoin

public QueryBuilder rightJoin(String join,
                              String on,
                              Object... params)

Only used for native sql.

Parameters:

join -

on -

params -

Returns:

rightJoin

public QueryBuilder rightJoin(String join,
                              String on)

joinIf

public QueryBuilder joinIf(String join,
                           String on,
                           boolean cond,
                           Object... params)

like joinIf(String, String, boolean, Object...) but join is performed iff cond evaluates to true.

Parameters:

join - join

on - on clause

cond - predicate

params - params

Returns:

this

join

public QueryBuilder join(String join)

Dont need 'on', used for JPQL.

Parameters:

join -

cond -

Returns:

joinIf

public QueryBuilder joinIf(String join,
                           boolean cond)

Dont need 'on', used for JPQL.

Parameters:

join -

cond -

Returns:

startAnd

public QueryBuilder.ConditionList<QueryBuilder> startAnd()

marks the beginning of a list of predicates to be ANDed.

Returns:

condition object

startOr

public QueryBuilder.ConditionList<QueryBuilder> startOr()

marks the beginning of a list of predicates to be ORed.

Returns:

condition object

endBuilder

public QueryBuilder endBuilder()

Mark this query as completed. TODO: what is the role of completed vs. non-completed queries?

Returns:

this

orderBy

public QueryBuilder orderBy(SortOrder sortOrder,
                            String orderBy)

appends the given column to the ordering restrictions iff not already ordered by the given column.

Parameters:

sortOrder - ASC or DESC

orderBy - the column to order by

Returns:

this

orderByIf

public QueryBuilder orderByIf(SortOrder sortOrder,
                              String orderBy,
                              boolean cond)

Appends given column to the ordering restrictions iff cond evaluates to true.

Parameters:

sortOrder - ASC or DESC

orderBy - column

cond - predicate

Returns:

this

applySelect

public SelectQuery applySelect(javax.persistence.EntityManager entityManager)

creates select query with the given EntityManager and stores the prepared query which is then executed through the getResultList() methods.

Parameters:

entityManager - em to use

Returns:

this

applySelect

public SelectQuery applySelect(javax.persistence.EntityManager entityManager,
                               Class<?> resultClass)

creates select query with the given EntityManager and stores the prepared query which is then executed through the getResultList() methods.

Parameters:

entityManager - em to use

resultClass - class of result

Returns:

this

applyCount

public CountQuery applyCount(javax.persistence.EntityManager entityManager)

creates count query with the given EntityManager and stores the prepared query which is then executed through the getCount() method.

Parameters:

entityManager - em to use

Returns:

this

setParameters

public void setParameters(List<Object> parameters)

Set parameters of the query.

Parameters:

parameters - the parameters to set

getResultList

public <T> List<T> getResultList(Class<T> clazz,
                                 int firstRow,
                                 int maxNumOfRows)

gets at most maxNumOfRows results, first one being firstRow.

Specified by:

getResultList in interface SelectQuery

Type Parameters:

T - entity type

Parameters:

clazz - entity class

firstRow - first row to receive

maxNumOfRows - max number of rows to receive

Returns:

retrieved entities

getResultList

public List<?> getResultList(int firstRow,
                             int maxNumOfRows)

Description copied from interface: SelectQuery

returns the results in the given range.

Specified by:

getResultList in interface SelectQuery

Parameters:

firstRow - first row

maxNumOfRows - maxNumOfRows

Returns:

list of results.

See Also:

getResultList(Class, int, int).

getResultList

public <T> List<T> getResultList(Class<T> clazz)

returns all entities matching the query.

Specified by:

getResultList in interface SelectQuery

Type Parameters:

T - entity type

Parameters:

clazz - entity class

Returns:

results

getRawResultList

public List<?> getRawResultList()

Returns:

query.getResultList()

getSingleResult

public <T> T getSingleResult(Class<T> clazz)

Specified by:

getSingleResult in interface SelectQuery

Type Parameters:

T - entity type

Parameters:

clazz - entity class

Returns:

the unique entity matching the query

getCount

public int getCount()

Specified by:

getCount in interface CountQuery

Returns:

the result.

append

public void append(String query)

TODO: this seems wrong. what's this for?

Specified by:

append in interface Expression

Parameters:

query - the query to append

toString

public String toString()

Overrides:

toString in class Object

Returns:

the select query as string.

getBodyParameters

public List<Object> getBodyParameters()

Get all attached parameters.

Returns:

the parameters

clearOrderBy

public QueryBuilder clearOrderBy()

drops all ordering constraints.

Returns:

this