ObjectReadFunction.java

/*
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package com.facebook.presto.plugin.jdbc.mapping.functions;

import com.facebook.presto.plugin.jdbc.mapping.ReadFunction;

import java.sql.ResultSet;
import java.sql.SQLException;

import static java.util.Objects.requireNonNull;

public interface ObjectReadFunction
        extends ReadFunction
{
    @Override
    Class<?> getJavaType();

    Object readObject(ResultSet resultSet, int columnIndex) throws SQLException;

    static <T> ObjectReadFunction of(Class<T> javaType, ObjectReadFunctionImplementation<T> implementation)
    {
        requireNonNull(javaType, "javaType is null");
        requireNonNull(implementation, "object read implementation is null");
        return new ObjectReadFunction() {
            @Override
            public Class<?> getJavaType()
            {
                return javaType;
            }

            @Override
            public Object readObject(ResultSet resultSet, int columnIndex) throws SQLException
            {
                return implementation.read(resultSet, columnIndex);
            }
        };
    }

    @FunctionalInterface
    interface ObjectReadFunctionImplementation<T>
    {
        T read(ResultSet resultSet, int columnIndex) throws SQLException;
    }
}