/*
 * JEF - Copyright 2009-2010 Jiyi (mr.jiyi@gmail.com)
 *
 * 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 jef.database.jdbc.result;

import java.sql.ResultSet;
import java.sql.ResultSetMetaData;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.List;
import java.util.Map;

import javax.persistence.PersistenceException;

import jef.database.Condition;
import jef.database.DbUtils;
import jef.database.dialect.DatabaseDialect;
import jef.database.jdbc.JDBCTarget;
import jef.database.meta.Reference;
import jef.database.wrapper.populator.ColumnMeta;

public final class ResultSetHolder extends AbstractResultSet implements IResultSet {
	private Statement st;
	ResultSet rs;
	private JDBCTarget db;

	public JDBCTarget getDb() {
		return db;
	}

	/**
	 * 构造
	 * 
	 * @param tx
	 * @param st
	 * @param rs
	 */
	public ResultSetHolder(JDBCTarget tx, Statement st, ResultSet rs) {
		this.db = tx;
		this.st = st;
		this.rs = rs;
	}

	/**
	 * 
	 * @param closeResultSet
	 *            是否关闭ResultSet
	 */
	public void close(boolean closeResultSet) {
		if (closeResultSet && rs != null) {
			DbUtils.close(rs);
			rs = null;
		}
		if (st != null) {
			DbUtils.close(st);
			st = null;
		}
		if (db != null) {
			db.releaseConnection();
			// 而目前设计约束凡是用户持有游标的场景，必须嵌套到一个内部的事务中去。因此实际上不会出现非当前线程的方法来释放连接的可能。
			// 如果是为了持有结果集专门设计的连接，那么直接就关闭掉
			if (db.isResultSetHolderTransaction()) {
				db.closeTx();
			}
			db = null;
		}
	}

	@Override
	public DatabaseDialect getProfile() {
		return db.getProfile();
	}

	@Override
	public ColumnMeta getColumns() {
		throw new UnsupportedOperationException();
	}

	@Override
	public boolean next() {
		try {
			ensureOpen();
			return rs.next();
		} catch (SQLException e) {
			throw new PersistenceException(e);
		}
	}

	private void ensureOpen() throws SQLException {
		if (rs == null) {
			throw new SQLException("The resultset was closed!");
		}
	}

	@Override
	public void afterLast() throws SQLException {
		ensureOpen();
		rs.afterLast();
	}

	@Override
	public void beforeFirst() throws SQLException {
		ensureOpen();
		rs.beforeFirst();
	}

	@Override
	public void close() throws SQLException {
		close(true);
	}

	@Override
	public boolean first() throws SQLException {
		ensureOpen();
		return rs.first();
	}

	@Override
	public ResultSetMetaData getMetaData() throws SQLException {
		ensureOpen();
		return rs.getMetaData();
	}

	@Override
	public boolean isClosed() throws SQLException {
		return rs.isClosed();
	}

	@Override
	public boolean previous() throws SQLException {
		ensureOpen();
		return rs.previous();
	}

	@Override
	protected ResultSet get() throws SQLException {
		// ensureOpen();
		return rs;
	}

	@Override
	public Map<Reference, List<Condition>> getFilters() {
		throw new UnsupportedOperationException();
	}

	@Override
	public boolean isBeforeFirst() throws SQLException {
		ensureOpen();
		return rs.isBeforeFirst();
	}

	@Override
	public boolean isAfterLast() throws SQLException {
		ensureOpen();
		return rs.isAfterLast();
	}

	@Override
	public boolean isFirst() throws SQLException {
		ensureOpen();
		return rs.isFirst();
	}

	@Override
	public boolean isLast() throws SQLException {
		ensureOpen();
		return rs.isLast();
	}

	@Override
	public boolean last() throws SQLException {
		ensureOpen();
		return rs.last();
	}
}