/*
 * UpdateOp.java
 */
package org.ngbw.sdk.database;


import java.io.IOException;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;


/**
 *
 * @author Paul Hoover
 *
 */
class UpdateOp implements RowOperation {

	// data fields


	private final String m_tableName;
	private final Criterion m_key;
	private final List<Column<?>> m_columns;


	// constructors


	/**
	 *
	 * @param tableName
	 * @param key
	 * @param columns
	 */
	UpdateOp(String tableName, Criterion key, List<Column<?>> columns)
	{
		m_tableName = tableName;
		m_key = key;
		m_columns = columns;
	}

	/**
	 *
	 * @param tableName
	 * @param key
	 * @param column
	 */
	UpdateOp(String tableName, Criterion key, Column<?> column)
	{
		m_tableName = tableName;
		m_key = key;
		m_columns = new ArrayList<Column<?>>();

		m_columns.add(column);
	}


	// public methods


	/**
	 *
	 * @param dbConn
	 * @return
	 * @throws IOException
	 * @throws SQLException
	 */
	@Override
	public void execute(Connection dbConn) throws IOException, SQLException
	{
		if (m_columns.isEmpty())
			return;

		StringBuilder stmtBuilder = new StringBuilder();
		Iterator<Column<?>> columns = m_columns.iterator();

		stmtBuilder.append("UPDATE ");
		stmtBuilder.append(m_tableName);
		stmtBuilder.append(" SET ");
		stmtBuilder.append(columns.next().getName());
		stmtBuilder.append(" = ?");

		while (columns.hasNext()) {
			stmtBuilder.append(", ");
			stmtBuilder.append(columns.next().getName());
			stmtBuilder.append(" = ?");
		}

		stmtBuilder.append(" WHERE ");
		stmtBuilder.append(m_key.getPhrase());

		PreparedStatement updateStmt = dbConn.prepareStatement(stmtBuilder.toString());

		try {
			int index = 1;

			for (columns = m_columns.iterator() ; columns.hasNext() ; index += 1)
				columns.next().setParameter(updateStmt, index);

			m_key.setParameter(updateStmt, index);

			updateStmt.executeUpdate();
		}
		finally {
			updateStmt.close();

			for (Column<?> col : m_columns)
				col.finishUpdate();
		}
	}
}