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https://issues.apache.org/jira/browse/JDO-652?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16613253#comment-16613253
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Andy Jefferson commented on JDO-652:
------------------------------------
I've updated the DN prototype to match Craig's ideas / namings, namely
*JDOQLTypedQuery* gains these methods
{code:java}
/**
* Method to return an "IF (...) ... ELSE ..." expression for use in this query.
* @param type The type returned by the IfElse.
* @return The IfThenElse expression
*/
<V> IfThenElseExpression<V> ifThenElse(Class<V> type);
/**
* Method to return an "IF (...) ... ELSE ..." expression for use in this query.
* @param type The type returned by the IfElse.
* @param ifExpr If expression
* @param ifValue Value to return when the if expression is met
* @param elseValue Value to return when the if expression is not met
* @return The IfThenElse expression
*/
<V> IfThenElseExpression<V> ifThenElse(Class<V> type, BooleanExpression
ifExpr, V ifValue, V elseValue);
/**
* Method to return an "IF (...) ... ELSE ..." expression for use in this query.
* @param type The type returned by the IfElse.
* @param ifExpr If expression
* @param ifValueExpr Expression for value to return when the if expression is
met
* @param elseValueExpr Expression for value to return when the if expression
is not met
* @return The IfThenElse expression
*/
<V> IfThenElseExpression<V> ifThenElse(Class<V> type, BooleanExpression
ifExpr, Expression<V> ifValueExpr, Expression<V> elseValueExpr);
{code}
and there is now *IfThenElseExpression* as follows
{code:java}
public interface IfThenElseExpression<T> extends ComparableExpression<T>
{
/**
* Method to add an "IF (...) ..." clause.
* If called multiple times, will add extra "IF (...) ..." or "ELSE IF (...)
..."
* @param ifExpr The if expression
* @param value The return value
* @return This expression
*/
IfThenElseExpression<T> when(BooleanExpression ifExpr, T value);
/**
* Method to add an "IF (...) ..." clause.
* If called multiple times, will add extra "IF (...) ..." or "ELSE IF (...)
..."
* @param ifExpr The if expression
* @param value The return value expression
* @return This expression
*/
IfThenElseExpression<T> when(BooleanExpression ifExpr, Expression<T>
valueExpr);
/**
* Method to add the "ELSE ..." clause.
* If called multiple times will replace the previous else clause
* @param value The return value
* @return This expression
*/
IfThenElseExpression<T> otherwise(T value);
/**
* Method to add the "ELSE ..." clause.
* If called multiple times will replace the previous else clause
* @param value The return value expression
* @return This expression
*/
IfThenElseExpression<T> otherwise(Expression<T> valueExpr);
}
{code}
The builder methods provided don't cater for the cases where the user wants to
provide a literal for the "if" value and expression for the "else" value (and
vice versa), but i'd put those as minority interest use-cases.
> Provision of a typesafe refactor-friendly query capability for JDOQL
> --------------------------------------------------------------------
>
> Key: JDO-652
> URL: https://issues.apache.org/jira/browse/JDO-652
> Project: JDO
> Issue Type: New Feature
> Components: api, specification, tck
> Reporter: Andy Jefferson
> Assignee: Michael Bouschen
> Priority: Major
> Fix For: JDO 3.2
>
> Attachments: JDO-652-api-patch-Andy.txt, JDO-652-patch3.txt,
> typesafe.patch, typesafe_manifest.patch
>
>
> There are various querying capabilities of this type around. JPA2 has its
> Criteria query API. Third party solutions like QueryDSL also exist, in its
> case providing a JDOQL implementation (as well as JPQL, and HQL). We should
> seriously consider introducing something along these lines in the JDO2.4
> timeframe.
> There is a comparison of JPA Criteria with QueryDSL over at
> http://source.mysema.com/forum/mvnforum/viewthread_thread,49
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