package org.simpleflatmapper.jdbc.spring;

import org.simpleflatmapper.jdbc.JdbcMapper;
import org.simpleflatmapper.jdbc.JdbcMapperFactory;
import org.simpleflatmapper.util.ListCollector;
import org.simpleflatmapper.util.CheckedConsumer;
import org.springframework.dao.DataAccessException;
import org.springframework.jdbc.core.PreparedStatementCallback;
import org.springframework.jdbc.core.ResultSetExtractor;
import org.springframework.jdbc.core.RowMapper;

import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.List;

/**
 * Provide integration point with Spring JdbcTemplate.
 * <p>
 * It implements {@link RowMapper}, {@link PreparedStatementCallback} and {@link ResultSetExtractor}.
 * Because some JdbcTemplate template signature match against a few of those type you might need to downcast, declare the variable with a specific type or use the type specific method in {@link JdbcTemplateMapperFactory}.
 *
 * <p>
 *
 * <code>
 * class MyDao {<br>
 *     private final JdbcTemplateMapper<DbObject> jdbcMapper =<br>
 *         JdbcTemplateMapperFactory.newInstance().newMapper(DbObject.class);<br>
 *     private final RowMapper<DbObject> rowMapper = jdbcMapper;<br>
 *<br>
 *     public void doSomething() {<br>
 *         List<DbObject> results = template.query(DbHelper.TEST_DB_OBJECT_QUERY, rowMapper);<br>
 *     }<br>
 *<br>
 *     public void doSomethingElse() {<br>
 *         template<br>
 *             .query(TEST_DB_OBJECT_QUERY,<br>
 *             jdbcMapper.newResultSetExtractor((o) -> System.out.println(o.toString())));<br>
 *     }<br>
 * }<br>
 *</code>
 *
 * @param <T> the mapped type
 * @see JdbcMapperFactory
 * @see JdbcMapper
 * @see JdbcTemplateMapperFactory#newPreparedStatementCallback(Class)
 * @see JdbcTemplateMapperFactory#newResultSetExtractor(Class)
 * @see JdbcTemplateMapperFactory#newRowMapper(Class)
 *
 */
public final class ResultSetExtractorImpl<T> implements ResultSetExtractor<List<T>> {
	private final JdbcMapper<T> mapper;

	public ResultSetExtractorImpl(JdbcMapper<T> mapper) {
		this.mapper = mapper;
	}

    @Override
    public List<T> extractData(ResultSet rs) throws SQLException,
            DataAccessException {
        return mapper.forEach(rs, new ListCollector<T>()).getList();
    }

	public <H extends CheckedConsumer<T>>  ResultSetExtractor<H> newResultSetExtractor(final H handler) {
		return new ResultSetExtractor<H>() {
			@Override
			public H extractData(ResultSet rs) throws SQLException,
					DataAccessException {
				return mapper.forEach(rs, handler);
			}
		};
	}


}