movieutil.java

java编程中的DAO模式举例,其他人不需帐号就可自由下载此源码

// $Header: /cvsroot/daoexamples/daoexamples/src/java/daoexamples/movie/MovieUtil.java,v 1.7 2003/09/27 17:27:11 sullis Exp $
 
/*
 * 
 *
 * 
 * 
 */
 
package daoexamples.movie;

import daoexamples.exception.*;
import java.sql.*;
import java.util.Collection;
import javax.sql.*;
import javax.naming.Context;
import javax.naming.InitialContext;
import javax.naming.NamingException;
import javax.transaction.UserTransaction;
import org.apache.commons.logging.*;

/**
 *
 * utilities for the Movie DAO package
 *  
 * @author Sean C. Sullivan
 * 
 */
public final class MovieUtil
{
	static final private Log log = LogFactory.getLog(MovieUtil.class);

	static public String getUniqueMovieId(final Connection conn)
		throws java.sql.SQLException
	{
		
		if (null == conn)
		{
			throw new NullPointerException("conn parameter");
		}

		if (conn.isClosed())
		{
			throw new IllegalArgumentException(
					"connection is closed");
		}

		String id = null;
		
		Statement stmtSelect = null;
		ResultSet rs = null;
		
		StringBuffer sbSelect = new StringBuffer();
		
		sbSelect.append("SELECT ");
		sbSelect.append(MovieConstants.MOVIE_ID_SEQUENCE_NAME);
		sbSelect.append(".nextval ");
		sbSelect.append(" FROM DUAL ");
		
		try
		{
			stmtSelect = conn.createStatement();
			rs = stmtSelect.executeQuery(sbSelect.toString());
			rs.next();
			id = rs.getString("nextval");
		}
		finally
		{
			MovieUtil.closeStatement(stmtSelect);
			MovieUtil.closeResultSet(rs);
		}
	
		return id;
	}
	
	/**
	 *  
	 * @param conn must be non-null
	 * 
	 * the caller is responsible for committing the transaction
	 * 
	 * @throws SQLException
	 * 
	 */
	static public void setupMovieTable()
		throws SQLException
	{
		Statement stmtCreateTable = null;
		Statement stmtDropTable = null;
		Statement stmtCreateSeq = null;
		Statement stmtDropSeq = null;
		
		Connection conn = null;
		
		try
		{
			//
			// 
			// This method uses a non-XA JDBC connection because
			// "DROP TABLE" and "CREATE TABLE" will only work
			// with a non-XA JDBC connection.
			//
			conn = MovieUtil.getNonXADBConnection();
			conn.setAutoCommit(true);

			log.debug(
				conn.getMetaData().getDriverName()
				+ " - "
				+ conn.getMetaData().getDriverVersion());
			
			StringBuffer sbDropTable = new StringBuffer();
			sbDropTable.append("DROP TABLE ");
			sbDropTable.append(MovieConstants.MOVIE_TABLE_NAME);
		
			stmtDropTable = conn.createStatement();
		
			try
			{
				stmtDropTable.execute(sbDropTable.toString());
			}
			catch (SQLException ignored)
			{
				// The 'DROP TABLE' statement may throw
				// an exception. We ignore it.
			} 
		
			StringBuffer sbDropSeq = new StringBuffer();
			sbDropSeq.append("DROP SEQUENCE ");
			sbDropSeq.append(MovieConstants.MOVIE_ID_SEQUENCE_NAME);
		
			stmtDropSeq = conn.createStatement();
		
			try
			{
				stmtDropSeq.execute(sbDropSeq.toString());
			}
			catch (SQLException ignored)
			{
				// The 'DROP SEQUENCE' statement may throw
				// an exception. We ignore it.
			} 

			StringBuffer sbCreateSeq = new StringBuffer();
			sbCreateSeq.append("CREATE SEQUENCE ");
			sbCreateSeq.append(MovieConstants.MOVIE_ID_SEQUENCE_NAME);
			sbCreateSeq.append(" START WITH 1 INCREMENT BY 1 NOMAXVALUE ORDER NOCACHE");
		
			stmtCreateSeq = conn.createStatement();
			stmtCreateSeq.execute(sbCreateSeq.toString());
		
			StringBuffer sbCreateTable = new StringBuffer();
			sbCreateTable.append("CREATE TABLE ");
			sbCreateTable.append(MovieConstants.MOVIE_TABLE_NAME);
			sbCreateTable.append(" ( ");
			sbCreateTable.append(" movie_id NUMBER(12), ");
			sbCreateTable.append(" rating VARCHAR2(10), ");
			sbCreateTable.append(" year VARCHAR2(5), ");
			sbCreateTable.append(" title VARCHAR2(60) ");
			sbCreateTable.append(" ) ");
		
			stmtCreateTable = conn.createStatement();
		
			log.debug("CREATE TABLE statement: "
						+ sbCreateTable.toString());

			stmtCreateTable.execute(sbCreateTable.toString());
			
			log.debug("Statement executed: "
								+ sbCreateTable.toString());
								
		}
		finally
		{
			MovieUtil.closeStatement(stmtDropTable);
			MovieUtil.closeStatement(stmtDropSeq);
			MovieUtil.closeStatement(stmtCreateTable);
			MovieUtil.closeStatement(stmtCreateSeq);
			MovieUtil.closeJDBCConnection(conn);
		}
	}
	
	private MovieUtil()
	{
		// this constructor is intentionally private
	}

	static public Connection getNonXADBConnection()
	{
		 Connection conn = null;
		 
		 DataSource ds = null;
		 
		 try
		 {
			Object obj = lookup(MovieConstants.MOVIE_NONXA_DATASOURCE_NAME);
			ds = (DataSource) narrow(obj, DataSource.class); 
		 	
			conn = ds.getConnection();
		 }
		 catch (SQLException ex)
		 {
			throw new DAORuntimeException(ex);
		 }
		 return conn;
	}

	public static Connection getXADBConnection()
	{
		 Connection conn = null;
		 
		 DataSource ds = null;
		 
		 try
		 {
			Object obj = lookup(MovieConstants.MOVIE_XA_DATASOURCE_NAME);
			ds = (DataSource) narrow(obj, DataSource.class); 
		 	
		 	conn = ds.getConnection();
		 }
		 catch (SQLException ex)
		 {
		 	throw new DAORuntimeException(ex);
		 }
		 
		 
		 return conn;
	}
	
	public static void closeJDBCConnection(final Connection conn)
	{
		if (conn != null)
		{
			 try
			 {
				conn.close();
			 }
			 catch (SQLException ex)
			 {
				log.error(conn, ex);
			 }
		}
	}

	public static void closeStatement(final Statement stmt)
	{
		if (stmt != null)
		{
			 try
			 {
				stmt.close();
			 }
			 catch (SQLException ex)
			 {
				log.error(stmt, ex);
			 }
		}
	}

	public static void closeResultSet(final ResultSet rs)
	{
		if (rs != null)
		{
			 try
			 {
				rs.close();
			 }
			 catch (SQLException ex)
			 {
				log.error(rs, ex);
			 }
		}
	}

	static public UserTransaction getUserTransaction()
	{
		Object obj = lookup("java:comp/UserTransaction");
		
		UserTransaction tx = (UserTransaction) narrow(obj, UserTransaction.class);
		
		return tx;
	} 

	static public Object lookup(final String name)
	{
		Context ctx = getInitialContext();
		
		Object result = null;
		
		try
		{
			result = ctx.lookup(name);
		}
		catch (NamingException ex)
		{
			throw new DAORuntimeException(ex);
		}
		
		return result;
	}
	
	static public Context getInitialContext()
	{
		Context ctx = null;

		try
		{
			ctx = new InitialContext();
		}
		catch (NamingException ex)
		{
			throw new DAORuntimeException(ex);
		}		
		return ctx; 
	}
	
	static public Object narrow(final Object obj, final Class clazz)
	{
		return javax.rmi.PortableRemoteObject.narrow(obj, clazz);
	}

	/**
	 *  
	 * @param rs must be non-null
	 * 
	 * @return a Collection containing zero or more {@link Movie} objects
	 * 
	 */
	static public Collection makeMovieObjectsFromResultSet(final ResultSet rs)
		throws java.sql.SQLException
	{
		Collection result = new java.util.ArrayList();
	
		while (rs.next())
		{
			String id = rs.getString("movie_id"); 	
			String rating = rs.getString("rating"); 	
			String year = rs.getString("year"); 	
			String title = rs.getString("title");
			Movie m = new MovieImpl(id, rating, year, title);
			result.add(m); 	
		}
		
		return result;
	}
			
}