Package nl.knaw.dans.lib.dataverse

Class QueryContext<T>

java.lang.Object

nl.knaw.dans.lib.dataverse.QueryContext<T>

All Implemented Interfaces:

AutoCloseable

public final class QueryContext<T>
extends Object
implements AutoCloseable

Context for executing a SQL query with multiple sets of parameters. Automatically manages the lifecycle of the database connection and prepared statement. This class is intended to be used for read-only queries and will set the connection to read-only mode.

Method Summary

Modifier and Type	Method	Description
void	close()
List<T>	executeFor(Iterable<Object[]> sets)	Executes the query for each set of parameters in the provided iterable, mapping each ResultSet row to an object of type T using the default mapper function.
<U> List<U>	executeFor(Iterable<Object[]> sets, Function<ResultSet,U> mapper)	Executes the query for each set of parameters in the provided iterable, mapping each ResultSet row to an object of type T using the provided mapper function.

Methods inherited from class java.lang.Object

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

Method Details

executeFor

public List<T> executeFor(Iterable<Object[]> sets)
                   throws SQLException

Executes the query for each set of parameters in the provided iterable, mapping each ResultSet row to an object of type T using the default mapper function. Automatically closes the ResultSet after processing each set of parameters. Note that types of parameters in the parameter sets must be compatible with the SQL query.

Parameters:

sets - an iterable of parameter sets, where each parameter set is an array of objects corresponding to the parameters in the SQL query

Returns:

a list of objects of type T resulting from executing the query for each set of parameters

Throws:

SQLException - when database access fails

executeFor

public <U> List<U> executeFor(Iterable<Object[]> sets,
 Function<ResultSet,U> mapper)
                       throws SQLException

Executes the query for each set of parameters in the provided iterable, mapping each ResultSet row to an object of type T using the provided mapper function. Automatically closes the ResultSet after processing each set of parameters. Note that types of parameters in the parameter sets must be compatible with the SQL query.

Type Parameters:

U - the type of objects to return in the list

Parameters:

sets - an iterable of parameter sets, where each parameter set is an array of objects corresponding to the parameters in the SQL query

mapper - a function that maps a ResultSet row to an object of type U

Returns:

a list of objects of type U resulting from executing the query for each set of parameters

Throws:

SQLException - when database access fails

close

public void close()
           throws SQLException

Specified by:

close in interface AutoCloseable

Throws:

SQLException