jtdao.java

来自「Java Pattern Oriented Framework (Jt) 是为了」· Java 代码 · 共 1,523 行 · 第 1/3 页

                return (this);
        } else
            return (null);

    }


    // propagateException: 

    private Exception propagateException (JtObject obj)
    {
        Exception ex;

        if (obj == null)
            return null;

        ex = (Exception) 
        getValue (obj, "objException");

        if (ex != null)
            setValue (this, "objException", ex);

        return (ex);
    }

    // resetExceptions: 

    private void resetExceptions ()
    {

        setValue (this, "objException", null);
        if (db != null)
            setValue (db, "objException", null);

    }


    // insert: insert record

    private Object insert () {
        JtMessage msg;
        String query;
        Object conn;
        PreparedStatement pst;
        Object out = null;

        msg = new JtMessage ();

        if (db == null)
            realize ();

        attr = getAttributes ();
        query = build_insert_query ();

        if (query == null || db == null)
            return (null);

        conn = this.getValue (db, "connection");

        // Connect to the data source

        if (conn == null) {
            msg.setMsgId (JtJDBCAdapter.JtCONNECT);
            this.sendMessage (db, msg);
            if (propagateException (db) != null)
                return (null);
        }

        msg.setMsgId (JtJDBCAdapter.JtPREPARE_STATEMENT);
        msg.setMsgContent (query);

        pst = (PreparedStatement) this.sendMessage (db, msg);

        if (pst == null)
            return (null);  // check

        setParameters (pst);

        msg.setMsgId (JtJDBCAdapter.JtEXECUTE_PREPARED_UPDATE);
        msg.setMsgContent (pst);
        out = this.sendMessage (db, msg);


        /*
     msg.setMsgId ("JtUPDATE");
     msg.setMsgContent (query);

     this.sendMessage (db, msg);
         */

        try {
            pst.close ();
        }
        catch (Exception ex) {
            handleException (ex);
        }

        propagateException (db);

        if (out == null)
            return (null);

        if (out instanceof Integer) {
            if (((Integer) out).intValue () != 1)
                return (null);
            else
                return (this);
        } else
            return (null);


    }

    /**
     * Specifies the Database Connection.
     */

    public void setConnection (Connection newConnection) {
        connection = newConnection;
    }


    /**
     * Returns the Database Connection.
     */

    public Connection getConnection () {
        return (connection);
    }


    /**
     * Specifies the name of the configuration file.
     */

    public void setConfigFile (String configFile) {
        this.configFile = configFile;
    }

    /**
     * Returns the name of the configuration file.
     */

    public String getConfigFile () {
        return (configFile);
    }
    private Hashtable getAttributes () {

        //Object args[];
        PropertyDescriptor[] prop;
        int i;
        //Class p;
        Method m;
        BeanInfo info = null;
        Object value;
        Hashtable attr;

        attr = new Hashtable ();

        if (map_table == null) {
            handleError 
            ("JtDAO.getAttributes: attributes/database mapping is missing");
            return (null);
        }

        try {
            info = Introspector.getBeanInfo(
                    this.getClass (), this.getClass ().getSuperclass());
        } catch(Exception e) {
            handleException (e);
            return (null);
        }

        prop = info.getPropertyDescriptors();
        for(i = 0; i < prop.length; i++) {
//          System.out.print ("Attribute:" + 
//          prop[i].getName());
            //p = prop[i].getPropertyType();

            try {
                m = prop[i].getReadMethod ();
                if (m == null) {
                    handleError 
                    ("JtDAO: getReadMethod returned null");
                    return (null);
                }

                if (getMapping (prop[i].getName()) == null)
                    continue;

                value = m.invoke (this, null);
                if (value == null) {
//                  attr.put (prop[i].getName(), value); 
                    continue;
                }

                if (value instanceof String) {
                    attr.put (prop[i].getName(), "'" + value + "'"); 
                    //System.out.println ("=" + value);
                    continue;
                }

                if (value instanceof Integer ||
                        value instanceof Long || 
                        value instanceof Float ||
                        value instanceof Byte ||
                        value instanceof Boolean ||
                        value instanceof Short ||
                        value instanceof Double ||
                        value instanceof Character) {
                    attr.put (prop[i].getName(), value.toString () ); 
                    //System.out.println ("=" + value);
                    continue;
                }

                if (value instanceof java.util.Date) {
                    attr.put (prop[i].getName(), value); 
                    continue;
                }

            } catch (Exception e) {
                handleException(e);
                return (null);
            }
        }

        return (attr);
    }

    private boolean validateAttribute (String att_name) {


        PropertyDescriptor[] prop;
        int i;
//      Class p;

        BeanInfo info = null;

        if (att_name == null)
            return (false);

        try {

            info = Introspector.getBeanInfo(
                    this.getClass (), this.getClass ().getSuperclass());
        } catch(Exception e) {
            handleException (e);
            return (false);
        }

        prop = info.getPropertyDescriptors();
        for(i = 0; i < prop.length; i++) {
//          System.out.print ("Attribute:" + 
//          prop[i].getName());
//          p = prop[i].getPropertyType();
            if ((prop[i].getName()).equals (att_name))
                return (true);
        }
        return (false);
    }

    private void print () {

        //Object args[];
        PropertyDescriptor[] prop;
        int i;
        //Class p;
        Method m;
        BeanInfo info = null;
        Object value;


        try {

            info = Introspector.getBeanInfo(
                    this.getClass (), this.getClass ().getSuperclass());
        } catch(Exception e) {
            handleException (e);
            return;
        }

        prop = info.getPropertyDescriptors();
        for(i = 0; i < prop.length; i++) {
//          System.out.print ("Attribute:" + 
//          prop[i].getName());
            //p = prop[i].getPropertyType();

            try {
                m = prop[i].getReadMethod ();
                if (m == null) {
                    handleError 
                    ("JtDAO: getReadMethod returned null");
                    return;
                }

                value = m.invoke (this, null);

                System.out.println (this.getClass ().getName () + "." +
                        prop[i].getName() + ":" + value);


            } catch (Exception e) {
                handleException(e);
            }
        }

    }

    /**
     * Specifies the attribute to be used as the database key.
     */

    public void setKey (Object key) {
        this.key = key;
    }

    /**
     * Returns the attribute to be used as the database key.
     */

    public Object getKey () {
        return (key);
    }


    /**
     * Specifies the name of the database table.
     */

    public void setTable (String table) {
        this.table = table;
    }


    /**
     * Returns the name of the database table.
     */

    public String getTable () {
        return (table);
    }

    private void readConfigFile () {
        JtMessage msg;
        JtObject cf;

        if (configFile == null)
            return;

        msg= new JtMessage ();

        msg.setMsgId (JtXMLMsgReader.JtPARSE);
        msg.setMsgReplyTo (this);

        cf = (JtObject) createObject (JtXMLMsgReader.JtCLASS_NAME, "configFile");
        setValue (cf, "uri", configFile);

        sendMessage (cf, msg);

    }
    private String build_key_query () {
        StringBuffer query = new StringBuffer ();
        String value;
        //Object tmp;
        //Enumeration keys; 
        //String att, tmp;
        String key_column;

        if (key == null ||  table == null)
            return (null);

        if (attr == null)
            return (null);

        value = (String) attr.get (key);

        if (value == null) {
            handleError ("build_key_query: invalid key (null)");
            return (null);
        }

        key_column = getMapping ((String) key);

        if (key_column == null) {
            handleError ("build_key_query: invalid mapping for "
                    + key);
            return (null);      
        }


        query.append ("Select Max (" + key_column + ") from " + table);   

        handleTrace ("query:" + query);

        return (query.toString ());

    }

    // calculateKey: calculate a new key

    private Object calculateKey () {
        JtMessage msg;
        String query;
        Object conn;
        ResultSet res;
        //Object out;
        long ltmp = 0L;
        Exception ex1;

        msg = new JtMessage ();

        if (db == null)
            realize ();

        attr = getAttributes (); // check

        query = build_key_query ();

        if (query == null || db == null)
            return (null);

        conn = this.getValue (db, "connection");

        // Connect to the data source

        if (conn == null) {
            msg.setMsgId (JtJDBCAdapter.JtCONNECT);
            this.sendMessage (db, msg);
            //return (propagateException (db));
        }

        msg.setMsgId (JtJDBCAdapter.JtEXECUTE_QUERY);
        msg.setMsgContent (query);

        res = (ResultSet) this.sendMessage (db, msg);
        ex1 = propagateException (db);

        if (ex1 != null)
            return (new Long (-1L));

        try
        {
            if (res.next()) {
                ltmp = res.getLong(1);           
            }
        }
        catch (Exception ex)
        {
            handleException (ex);
            return (new Long (-1L));
        }
        return (new Long(ltmp+1));

    }

    void realize () {
        //JtMessage msg;

        handleTrace ("JtDAO:realize");

        if (db != null)
            return;

        //msg = new JtMessage ();

        db = (JtObject) this.createObject (JtJDBCAdapter.JtCLASS_NAME, "db");
        // this.setValue (db, "objTrace", "1"); // check

        if (configFile != null)
            readConfigFile ();
    }

    void destroy () {
        if (db == null)
            return;
        //sendMessage (db, new JtMessage ("JtCLOSE"));
        closeConnection ();
        db = null;

    }

    private static void test () {
        JtObject main;
        //String query;
        JtMessage msg;

        main = new JtObject ();
//      main.setValue (main, "objTrace", "1");
        main.createObject (JtMessage.JtCLASS_NAME, "message");
        msg = new JtMessage ();

        main.createObject (JtDAO.JtCLASS_NAME, "dao");
//      main.setValue ("dao", "objTrace", "1");

        msg.setMsgId (JtObject.JtREALIZE);
        main.sendMessage ("dao", msg);
    }

    /**
     * Demonstrates the messages processed by JtDAO.
     */

    public static void main (String[] args) {

        test ();
    }
}