src/org/mxchange/jcore/database/backend/BaseDatabaseBackend.java

   1 /*
   2  * Copyright (C) 2015 Roland Haeder
   3  *
   4  * This program is free software: you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License as published by
   6  * the Free Software Foundation, either version 3 of the License, or
   7  * (at your option) any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  16  */
  17 package org.mxchange.jcore.database.backend;
  18
  19 import java.io.IOException;
  20 import java.lang.reflect.InvocationTargetException;
  21 import java.sql.Driver;
  22 import java.sql.DriverManager;
  23 import java.sql.SQLException;
  24 import java.text.MessageFormat;
  25 import java.util.Enumeration;
  26 import org.mxchange.jcore.BaseFrameworkSystem;
  27 import org.mxchange.jcore.criteria.searchable.SearchableCriteria;
  28 import org.mxchange.jcore.database.result.Result;
  29 import org.mxchange.jcore.database.storage.Storable;
  30 import org.mxchange.jcore.exceptions.BadTokenException;
  31 import org.mxchange.jcore.exceptions.CorruptedDatabaseFileException;
  32 import org.mxchange.jcore.exceptions.UnsupportedDatabaseDriverException;
  33
  34 /**
  35  * Generall database backend
  36  *
  37  * @author Roland Haeder
  38  */
  39 public abstract class BaseDatabaseBackend extends BaseFrameworkSystem {
  40
  41         /**
  42          * No instances from this class
  43          */
  44         protected BaseDatabaseBackend () {
  45         }
  46
  47         /**
  48          * Validates driver name and throws an exception if the driver is not valid
  49          *
  50          * @param driverName Driver name (e.g. "mysql")
  51          * @throws org.mxchange.jcore.exceptions.UnsupportedDatabaseDriverException If the given driver name cannot be solved into a driver instance
  52          */
  53         protected void validateDriver (final String driverName) throws UnsupportedDatabaseDriverException {
  54                 // Trace message
  55                 this.getLogger().trace(MessageFormat.format("driverName={0} - CALLED!", driverName)); //NOI18N
  56
  57                 // driverName shall not be null
  58                 if (null == driverName) {
  59                         // Is null
  60                         throw new NullPointerException("driverName is null");
  61                 }
  62
  63                 // Get all registered/installed drivers
  64                 Enumeration<Driver> drivers = DriverManager.getDrivers();
  65
  66                 // Default is not found
  67                 boolean isFound = false;
  68
  69                 // Search for it
  70                 while (drivers.hasMoreElements()) {
  71                         // Get element
  72                         Driver driver = drivers.nextElement();
  73
  74                         // Debug message
  75                         this.getLogger().debug(MessageFormat.format("Driver {0} is installed.", driver)); //NOI18N
  76
  77                         // Get class name
  78                         String className = driver.getClass().getName();
  79
  80                         // Debug message
  81                         this.getLogger().debug(MessageFormat.format("className={0}", className));
  82
  83                         // Is this wanted?
  84                         if (className.contains(driverName)) {
  85                                 // Debug message
  86                                 this.getLogger().debug("Found driver!"); //NOI18N
  87
  88                                 // Found it
  89                                 isFound = true;
  90                                 break;
  91                         }
  92                 }
  93
  94                 // Debug message
  95                 this.getLogger().debug("isFound=" + isFound);
  96
  97                 // Is it found?
  98                 if (!isFound) {
  99                         // Throw exception
 100                         throw new UnsupportedDatabaseDriverException(driverName);
 101                 }
 102
 103                 // Trace message
 104                 this.getLogger().trace("EXIT!"); //NOI18N
 105         }
 106
 107         public int numRows (final SearchableCriteria criteria) throws IOException, SQLException, BadTokenException, CorruptedDatabaseFileException, NoSuchMethodException, IllegalAccessException, InvocationTargetException {
 108                 // Trace message
 109                 this.getLogger().trace("criteria=" + criteria + " - CALLED!");
 110
 111                 // Criteria should not be null
 112                 if (null == criteria) {
 113                         // Abort here
 114                         throw new NullPointerException("criteria is null");
 115                 }
 116
 117                 // Run "SELECT"
 118                 Result<? extends Storable> result = this.doSelectByCriteria(criteria);
 119
 120                 // Get size
 121                 int numRows = result.size();
 122
 123                 // Trace message
 124                 this.getLogger().trace("numRows=" + numRows + " - EXIT!");
 125
 126                 // Return it
 127                 return numRows;
 128         }
 129
 130         /**
 131          *  Runs a SELECT "query" on database backend
 132          *
 133          * @param criteria Criteria instance
 134          * @return Result instance
 135          * @throws java.io.IOException If any IO error occurs
 136          * @throws org.mxchange.jcore.exceptions.BadTokenException If a bad token was found
 137          * @throws org.mxchange.jcore.exceptions.CorruptedDatabaseFileException If the file is badly damaged
 138          * @throws java.sql.SQLException If any SQL error occurs
 139          * @throws java.lang.NoSuchMethodException If a method was not found
 140          * @throws java.lang.IllegalAccessException If the method cannot be accessed
 141          * @throws java.lang.reflect.InvocationTargetException Any other problems?
 142          */
 143         public abstract Result<? extends Storable> doSelectByCriteria (SearchableCriteria criteria) throws IOException, SQLException, BadTokenException, CorruptedDatabaseFileException, NoSuchMethodException, IllegalAccessException, IllegalArgumentException, InvocationTargetException;
 144 }