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/*
* Copyright (c) 2009 Concurrent, Inc.
*
* This work has been released into the public domain
* by the copyright holder. This applies worldwide.
*
* In case this is not legally possible:
* The copyright holder grants any entity the right
* to use this work for any purpose, without any
* conditions, unless such conditions are required by law.
*/
package parallelai.spyglass.jdbc.db;
import org.apache.hadoop.io.Writable;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
/**
* Objects that are read from/written to a database should implement <code>DBWritable</code>.
* DBWritable, is similar to {@link Writable} except that the {@link #write(PreparedStatement)}
* method takes a {@link PreparedStatement}, and {@link #readFields(ResultSet)} takes a {@link
* ResultSet}. <p> Implementations are responsible for writing the fields of the object to
* PreparedStatement, and reading the fields of the object from the ResultSet. <p/> <p>Example:</p>
* If we have the following table in the database :
* <pre>
* CREATE TABLE MyTable (
* counter INTEGER NOT NULL,
* timestamp BIGINT NOT NULL,
* );
* </pre>
* then we can read/write the tuples from/to the table with :
* <p><pre>
* public class MyWritable implements Writable, DBWritable {
* // Some data
* private int counter;
* private long timestamp;
* <p/>
* //Writable#write() implementation
* public void write(DataOutput out) throws IOException {
* out.writeInt(counter);
* out.writeLong(timestamp);
* }
* <p/>
* //Writable#readFields() implementation
* public void readFields(DataInput in) throws IOException {
* counter = in.readInt();
* timestamp = in.readLong();
* }
* <p/>
* public void write(PreparedStatement statement) throws SQLException {
* statement.setInt(1, counter);
* statement.setLong(2, timestamp);
* }
* <p/>
* public void readFields(ResultSet resultSet) throws SQLException {
* counter = resultSet.getInt(1);
* timestamp = resultSet.getLong(2);
* }
* }
* </pre></p>
*/
public interface DBWritable {
/**
* Sets the fields of the object in the {@link PreparedStatement}.
*
* @param statement the statement that the fields are put into.
* @throws SQLException
*/
public void write(PreparedStatement statement) throws SQLException;
/**
* Reads the fields of the object from the {@link ResultSet}.
*
* @param resultSet the {@link ResultSet} to get the fields from.
* @throws SQLException
*/
public void readFields(ResultSet resultSet) throws SQLException;
}
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