com.nortal.petit.converter.util.PairRowMapper.java Source code

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Here is the source code for com.nortal.petit.converter.util.PairRowMapper.java

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/**
 *   Copyright 2014 Nortal AS
 *
 *   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.nortal.petit.converter.util;

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

import org.apache.commons.lang3.tuple.Pair;
import org.springframework.jdbc.core.RowMapper;

import com.nortal.petit.converter.util.ResultSetHelper.Type;

/**
 * RowMapper for generic Pair. Note that we need to provide Class arguments
 * since generic type information is nowhere to be found at runtime and we
 * cannot decide which method to invoke. Wait for runtime generics in Java! %)
 * Watch for default values ('key', 'value') for field names and (String,
 * String) for field classes.
 * 
 * @author Aleksei Lissitsin <aleksei.lissitsin@webmedia.ee>
 */
public class PairRowMapper<T, K> implements RowMapper<Pair<T, K>> {
    private final String keyField;
    private final String valueField;
    private final Type keyType;
    private final Type valueType;

    public PairRowMapper() {
        this("key", "value");
    }

    public PairRowMapper(String keyField, String valueField) {
        this.keyField = keyField;
        this.valueField = valueField;
        this.keyType = Type.STRING;
        this.valueType = Type.STRING;
    }

    public PairRowMapper(Class<T> keyClass, Class<K> valueClass) {
        this("key", "value", keyClass, valueClass);
    }

    public PairRowMapper(String keyField, String valueField, Class<T> keyClass, Class<K> valueClass) {
        this.keyField = keyField;
        this.valueField = valueField;
        this.keyType = ResultSetHelper.convertToType(keyClass);
        this.valueType = ResultSetHelper.convertToType(valueClass);
    }

    @SuppressWarnings("unchecked")
    public Pair<T, K> mapRow(ResultSet rs, int arg1) throws SQLException {
        T key = (T) ResultSetHelper.get(keyType, rs, keyField);
        K value = (K) ResultSetHelper.get(valueType, rs, valueField);
        return Pair.of(key, value);
    }
}