Files
ebean/src/main/java/io/ebean/DtoQuery.java
T

134 lines
3.6 KiB
Java

package io.ebean;
import javax.annotation.Nonnull;
import javax.annotation.Nullable;
import java.util.List;
import java.util.Optional;
import java.util.function.Consumer;
import java.util.function.Predicate;
/**
* Query for performing native SQL queries that return DTO Bean's.
* <p>
* These beans are just normal classes. They must have public constructors
* and setters.
* <p>
* Constructors with arguments are used if the number of constructor arguments
* matches the number of columns in the resultSet.
* </p>
* <p>
* If the number of columns in the resultSet is greater than the largest constructor
* then the largest constructor is used for the first columns and remaining columns
* are mapped by setter methods.
* </p>
*
* <pre>{@code
*
* // CustomerDto is just a 'bean like' class
* // with public constructor(s) and public setter methods
*
* String sql = "select id, name from customer where name like :name and status_code = :status";
*
* List<CustomerDto> beans =
* DB.findDto(CustomerDto.class, sql)
* .setParameter("name", "Acme%")
* .setParameter("status", "ACTIVE")
* .findList();
*
* }</pre>
*/
public interface DtoQuery<T> {
/**
* Execute the query returning a list.
*/
@Nonnull
List<T> findList();
/**
* Execute the query iterating a row at a time.
* <p>
* This streaming type query is useful for large query execution as only 1 row needs to be held in memory.
* </p>
*/
void findEach(Consumer<T> consumer);
/**
* Execute the query iterating a row at a time with the ability to stop consuming part way through.
* <p>
* Returning false after processing a row stops the iteration through the query results.
* </p>
* <p>
* This streaming type query is useful for large query execution as only 1 row needs to be held in memory.
* </p>
*/
void findEachWhile(Predicate<T> consumer);
/**
* Execute the query returning a single bean.
*/
@Nullable
T findOne();
/**
* Execute the query returning an optional bean.
*/
@Nonnull
Optional<T> findOneOrEmpty();
/**
* The same as bind for named parameters.
*/
DtoQuery<T> setParameter(String name, Object value);
/**
* The same as bind for positioned parameters.
*/
DtoQuery<T> setParameter(int position, Object value);
/**
* Set the index of the first row of the results to return.
*/
DtoQuery<T> setFirstRow(int firstRow);
/**
* Set the maximum number of query results to return.
*/
DtoQuery<T> setMaxRows(int maxRows);
/**
* When resultSet columns are not able to be mapped to a bean property then instead of
* throwing effectively skip reading that column.
*/
DtoQuery<T> setRelaxedMode();
/**
* Set a label on the query to make it easier to identify queries related to query execution statistics.
*
* @param label A label that is unique to the DTO bean type.
*/
DtoQuery<T> setLabel(String label);
/**
* Set a timeout on this query.
* <p>
* This will typically result in a call to setQueryTimeout() on a
* preparedStatement. If the timeout occurs an exception will be thrown - this
* will be a SQLException wrapped up in a PersistenceException.
* </p>
*
* @param secs the query timeout limit in seconds. Zero means there is no limit.
*/
DtoQuery<T> setTimeout(int secs);
/**
* A hint which for JDBC translates to the Statement.fetchSize().
* <p>
* Gives the JDBC driver a hint as to the number of rows that should be
* fetched from the database when more rows are needed for ResultSet.
* </p>
*/
DtoQuery<T> setBufferFetchSizeHint(int bufferFetchSizeHint);
}