DBParamManager.java

Go to the documentation of this file.

package cedar.jetweb.db;

import cedar.jetweb.model.parameters.Param;
import cedar.jetweb.model.parameters.ArrayParam;
import cedar.jetweb.model.parameters.ParamCollection;
import cedar.jetweb.model.parameters.ArrayCollection;
import cedar.jetweb.JetWebException;

import java.util.Vector;
import java.lang.reflect.*;

import java.sql.*;

public abstract class DBParamManager {
    private static DBObjectManager objManager = new DBObjectManager();

    private static boolean initialised_ = false;

    private static PreparedStatement insertCollection_;
    
    private static PreparedStatement selectById_;

    private static void init(){
    
    if(initialised_) return;
    initialised_ = true;
    try{
    selectById_ = DBConfig.getConnection().prepareStatement
        ("SELECT * FROM ? WHERE param_id=?");

    insertCollection_ = DBConfig.getConnection().prepareStatement
        ("INSERT INTO ? (collection_id, param_id) VALUES (?, ?)");

    }catch(SQLException err){
        
        System.out.println
        ("Error: cannot initialise prepared statements for "+
         "inserting and retrieving parameters from the DB");
        System.out.println(err.getMessage());
        err.printStackTrace();

    }
    return;
    }

    public static <T> void toDB(Param<T> param)
    throws JetWebException{

    String tableName = tableName(param);

    if(param.getParamId()<0){
        param.setParamId(DBUtil.getNextIndex("param_id", tableName));
    }

    objManager.writeObject(param, tableName, "jetweb");

    return;
    }

    public static <T> void toDB(ParamCollection<T> pc)
    throws JetWebException{

    if(pc.size()==0) return;

    Vector<Param<T> > params = pc.getParams();

    String tableName = tableName(params.get(0));
    tableName = tableName.substring(0, tableName.lastIndexOf("_"));
    tableName = tableName + "collection";

    Integer id = pc.getCollectionId();

    if(id < 0){
        id = DBUtil.getNextIndex("collection_id", tableName);
        pc.setCollectionId(id);
    }

    try{
        insertCollection_.setString(1,tableName);
        insertCollection_.setInt(2, pc.getCollectionId());

        for(Param param: pc.getParams()){
        insertCollection_.setInt(3,param.getParamId());
        insertCollection_.executeUpdate();
        }

    }catch(SQLException err){
        throw new JetWebException(err);
    }



    return;
    }


    public static <T> Integer matchId(Param<T> param)
    throws JetWebException{

    Integer id = -1;
    
    Vector<Method> methods = DBUtil.availableMethods(param, "get");

    String select = "SELECT param_id FROM " + tableName(param) + " WHERE ";
    Integer numCols = methods.size();
    Integer stop  = numCols - 1;
    for(int ii=0; ii!= numCols; ++ii){
        try{
        select = select + 
            DBUtil.unCamelMe(methods.get(ii).getName().substring(3)) + 
            "='" + methods.get(ii).invoke(param);
        if(ii!=stop){
            select = select + " AND ";
        }
        }catch(Exception err){
        throw new JetWebException(err);
        }
    }

    try{
        Statement stmt = DBConfig.getConnection().createStatement();
        ResultSet rs = stmt.executeQuery(select);
        
        if(rs!=null && rs.next()){
        id = rs.getInt(1);
        }
    }catch(SQLException err){
        throw new JetWebException(err);
    }
    return id;
    }

    public static boolean selectById(Param param)
    throws JetWebException{
    boolean success = false;
    String select = "SELECT * FROM " + tableName(param) + 
        " WHERE param_id="+param.getParamId();

    int numFilled = 0;

    try{
        selectById_.setString(1, tableName(param));
        selectById_.setInt(2, param.getParamId());
        //Statement stmt = DBConfig.getConnection().createStatement();
        //ResultSet rs = stmt.executeQuery(select);
        ResultSet rs = selectById_.executeQuery();

        numFilled = objManager.fillObject(param, rs);
    }catch(Exception err){
        throw new JetWebException(err);
    }

    if(numFilled >=3) success = true;

    return success;
    };

    private static <T> String tableName(Param<T> param){

    T val = param.getValue();

    String TName = param.getValue().getClass().getName();

    TName = TName.substring(TName.lastIndexOf(".") + 1);

    String paramName = param.getClass().getName();
    paramName = paramName.substring(paramName.lastIndexOf(".") + 1);

    String fullName = DBUtil.unCamelMe(TName) + "_" + 
        DBUtil.unCamelMe(paramName);

    return fullName;
    }

}

Generated Wed Jan 17 09:14:27 GMT 2007