| es.udc.mypersonalizer.kernel.model.query.executor.QueryExecutorDelegate
All known Subclasses: es.udc.mypersonalizer.kernel.model.query.executor.sql.SQLQueryExecutorDelegate,
QueryExecutorDelegate | public interface QueryExecutorDelegate (Code) | | Interface for query executors.
Query executors are classes which execute the query (or part of it) on
a given persistence type. They can make use of specific back-end features,
process data in memory, or combine both approaches.
Implementations of this interface are assumed to be not thread-safe.
If the query spans multiple MetaService s, with different
persistente methods, the implementations of this interface must
use
es.udc.mypersonalizer.kernel.model.query.executor.QueryExecutorDelegateFactory to obtain a suitable delegate and process its results. By using this
mechanism, a query can be resolved by a chain of
QueryExecutorDelegate s.
author: Abel Muinho since: 1.0 |
Method Summary | |
public PropertyListExpression | evaluate(Query query) Performs a query using the information given.
Depending on the target property (the property referenced by the last
step of the result clause), the value returned by a call to this method
must be:
- If the target is a
SimpleMetaProperty , the
result must be a list of correspondant
MetaSimplePropery objects.
- If the target is a
MetaCompoundProperty , the result
must be a list of correspondant MetaCompoundProperty
objects, with all its real children (that is, not including
any virtual property, so not spanning different
MetaService s.
- If the target is a
MetaService , its root
MetaCompoundProperty should be used.
See Also: es.udc.mypersonalizer.kernel.model.metainfo.MetaProperty See Also: es.udc.mypersonalizer.kernel.model.metainfo.MetaService Parameters: query - The query to evaluate. | public PropertyListExpression | evaluate(Query query, int start, int count) Similar to evaluate(Query) but allows to specify the
range of properties to retrieve.
The start and count parameters are relative
to the query order, as specified by the order by clause
or the query executor delegate idea of document order if
no explicit ordering has been requested.
start offset is zero-based.
See Also: QueryExecutorDelegate.evaluate(Query) Parameters: query - the query to evaluate. Parameters: start - the first property to be returned. Parameters: count - number of properties to be returned from start . |
evaluate | public PropertyListExpression evaluate(Query query) throws InternalErrorException(Code) | | Performs a query using the information given.
Depending on the target property (the property referenced by the last
step of the result clause), the value returned by a call to this method
must be:
- If the target is a
SimpleMetaProperty , the
result must be a list of correspondant
MetaSimplePropery objects.
- If the target is a
MetaCompoundProperty , the result
must be a list of correspondant MetaCompoundProperty
objects, with all its real children (that is, not including
any virtual property, so not spanning different
MetaService s.
- If the target is a
MetaService , its root
MetaCompoundProperty should be used.
See Also: es.udc.mypersonalizer.kernel.model.metainfo.MetaProperty See Also: es.udc.mypersonalizer.kernel.model.metainfo.MetaService Parameters: query - The query to evaluate. a list of properties as described by the result clause in theorder specified by the order clause (or in document order if noorder walker has been specified). throws: InternalErrorException - if the query can not be executed. |
evaluate | public PropertyListExpression evaluate(Query query, int start, int count) throws InternalErrorException(Code) | | Similar to evaluate(Query) but allows to specify the
range of properties to retrieve.
The start and count parameters are relative
to the query order, as specified by the order by clause
or the query executor delegate idea of document order if
no explicit ordering has been requested.
start offset is zero-based.
See Also: QueryExecutorDelegate.evaluate(Query) Parameters: query - the query to evaluate. Parameters: start - the first property to be returned. Parameters: count - number of properties to be returned from start . a list of properties as described by the result clause in theorder specified by the order clause (or in document order if noorder walker has been specified). throws: InternalErrorException - if the query can not be executed. |
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