/*

  Wotonomy: OpenStep design patterns for pure Java applications.

  Copyright (C) 2001 Michael Powers

  This library is free software; you can redistribute it and/or

  modify it under the terms of the GNU Lesser General Public

  License as published by the Free Software Foundation; either

  version 2.1 of the License, or (at your option) any later version.

  This library is distributed in the hope that it will be useful,

  but WITHOUT ANY WARRANTY; without even the implied warranty of

  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

  Lesser General Public License for more details.

  You should have received a copy of the GNU Lesser General Public

  License along with this library; if not, see http://www.gnu.org

  */

 package net.wotonomy.access;

 import net.wotonomy.control.EOFetchSpecification;

 import net.wotonomy.control.EOQualifier;

 import net.wotonomy.foundation.NSArray;

 import net.wotonomy.foundation.NSDictionary;

 import net.wotonomy.foundation.NSMutableDictionary;

 /**

 *

 * @author ezamudio@nasoft.com

 * @author $Author: cgruber $

 * @version $Revision: 894 $

 */

 public abstract class EOAdaptorChannel {

         protected EOAdaptorContext _context;

         public EOAdaptorChannel(EOAdaptorContext context) {

                 super();

                 _context = context;

         }

         public EOAdaptorContext adaptorContext() {

                 return _context;

         }

         public void addStoredProceduresNamed(NSArray names, EOModel model) {

         }

         public abstract NSArray attributesToFetch();

         public abstract void cancelFetch();

         public abstract void closeChannel();

         public abstract NSArray describeResults();

         public abstract int deleteRowsDescribedByQualifier(EOQualifier q, EOEntity entity);

         public abstract void evaluateExpression(EOSQLExpression sql);

         public abstract void executeStoredProcedure(EOStoredProcedure proc, NSDictionary values);

         public abstract NSMutableDictionary fetchRow();

         public abstract void insertRow(NSDictionary row, EOEntity entity);

         public abstract boolean isFetchInProgress();

         public abstract boolean isOpen();

         public abstract void openChannel();

         public abstract NSDictionary returnValuesForLastStoredProcedureInvocation();

         public abstract void selectAttributes(NSArray atts, EOFetchSpecification fspec, boolean lock, EOEntity entity);

         public abstract void setAttributesToFetch(NSArray atts);

         public abstract int updateValuesInRowsDescribedByQualifier(NSDictionary row, EOQualifier q, EOEntity entity);

         public void deleteRowDescribedByQualifier(EOQualifier q, EOEntity entity) {

                 adaptorContext().beginTransaction();

                 int count = deleteRowsDescribedByQualifier(q, entity);

                 if (count != 1) {

                         adaptorContext().rollbackTransaction();

                         throw new EOGeneralAdaptorException("Qualifier deleted " + count + " rows instead of exactly one.");

                 }

                 adaptorContext().commitTransaction();

         }

         public EOModel describeModelWithTableNames(NSArray names) {

                 return null;

         }

         public NSArray describeStoredProcedureNames() {

                 return NSArray.EmptyArray;

         }

         public NSArray describeTableNames() {

                 return NSArray.EmptyArray;

         }

         public NSMutableDictionary dictionaryWithObjectsForAttributes(Object[] values, NSArray attributes) {

                 Object[] keys = new Object[attributes.count()];

                 for (int i = 0; i < attributes.count(); i++)

                         keys[i] = ((EOAttribute)attributes.objectAtIndex(i)).name();

                 return new NSMutableDictionary(values, keys);

         }

         public void lockRowComparingAttributes(NSArray atts, EOEntity entity, EOQualifier q, NSDictionary snapshot) {

                 EOFetchSpecification fspec = new EOFetchSpecification(entity.name(), q, null);

                 adaptorContext().beginTransaction();

                 selectAttributes(atts, fspec, true, entity);

                 if (isFetchInProgress()) {

                         NSDictionary row = fetchRow();

                         if (row == null) {

                                 cancelFetch();

                                 adaptorContext().rollbackTransaction();

                                 throw new EOGeneralAdaptorException("Cannot obtain row to lock. Probably modified from the outside.");

                         }

                         if (isFetchInProgress()) {

                                 if (fetchRow() != null) {

                                         cancelFetch();

                                         adaptorContext().rollbackTransaction();

                                         throw new EOGeneralAdaptorException("Qualifier returns more than one row.");

                                 }

                         }

                         java.util.Enumeration enumeration = snapshot.keyEnumerator();

                         while (enumeration.hasMoreElements()) {

                                 Object key = enumeration.nextElement();

                                 Object svalue = snapshot.objectForKey(key);

                                 Object rvalue = row.objectForKey(key);

                                 if (rvalue == null) {

                                         cancelFetch();

                                         adaptorContext().rollbackTransaction();

                                         throw new EOGeneralAdaptorException("Value for key " + key + " not found in locked row.");

                                 }

                                 if (!rvalue.equals(svalue)) {

                                         cancelFetch();

                                         adaptorContext().rollbackTransaction();

                                         throw new EOGeneralAdaptorException("Value for key " + key + " differes from snapshot.");

                                 }

                         }

                         adaptorContext().commitTransaction();

                         return;

                 }

                 adaptorContext().rollbackTransaction();

                 throw new EOGeneralAdaptorException("A fetch was never generated.");

         }

         public void performAdaptorOperation(EOAdaptorOperation operation) {

                 int opcode = operation.adaptorOperator();

                 switch (opcode) {

                         case EODatabaseOperation.AdaptorLockOperator:

                                 if (operation.entity() == null)

                                         throw new EOGeneralAdaptorException("A lock operation must have an entity assigned to it.",

                                                 new NSDictionary(operation, "operation"));

                                 if (operation.qualifier() == null)

                                         throw new EOGeneralAdaptorException("A lock operation must have a qualifier assigned to it.",

                                                 new NSDictionary(operation, "operation"));

                                 if (operation.qualifier() == null)

                                         throw new EOGeneralAdaptorException("A lock operation must have changedValues assigned to it.",

                                                 new NSDictionary(operation, "operation"));

                                 lockRowComparingAttributes(operation.attributes(), operation.entity(), operation.qualifier(), operation.changedValues());

                                 break;

                         case EODatabaseOperation.AdaptorInsertOperator:

                                 if (operation.entity() == null)

                                         throw new EOGeneralAdaptorException("An insert operation must have an entity assigned to it.",

                                                 new NSDictionary(operation, "operation"));

                                 if (operation.changedValues() == null)

                                         throw new EOGeneralAdaptorException("An insert operation must have changedValues assigned to it.",

                                                 new NSDictionary(operation, "operation"));

                                 insertRow(operation.changedValues(), operation.entity());

                                 break;

                         case EODatabaseOperation.AdaptorUpdateOperator:

                                 if (operation.entity() == null)

                                         throw new EOGeneralAdaptorException("An update operation must have an entity assigned to it.",

                                                 new NSDictionary(operation, "operation"));

                                 if (operation.changedValues() == null)

                                         throw new EOGeneralAdaptorException("An update operation must have changedValues assigned to it.",

                                                 new NSDictionary(operation, "operation"));

                                 updateValuesInRowsDescribedByQualifier(operation.changedValues(), operation.qualifier(), operation.entity());

                                 break;

                         case EODatabaseOperation.AdaptorDeleteOperator:

                                 if (operation.entity() == null)

                                         throw new EOGeneralAdaptorException("A delete operation must have an entity assigned to it.",

                                                 new NSDictionary(operation, "operation"));

                                 deleteRowsDescribedByQualifier(operation.qualifier(), operation.entity());

                                 break;

                         case EODatabaseOperation.AdaptorStoredProcedureOperator:

                                 if (operation.storedProcedure() == null)

                                         throw new EOGeneralAdaptorException("A stored procedure operation must have a stored procedure assigned to it.",

                                                 new NSDictionary(operation, "operation"));

                                 executeStoredProcedure(operation.storedProcedure(), operation.changedValues());

                                 break;

                         default:

                                 throw new EOGeneralAdaptorException("I don't know how to perform an operation with code " + opcode,

                                         new NSDictionary(operation, "operation"));

                 }

         }

         public void performAdaptorOperations(NSArray ops) {

                 for (int i = 0; i < ops.count(); i++) {

                         EOAdaptorOperation adop = (EOAdaptorOperation)ops.objectAtIndex(i);

                         performAdaptorOperation(adop);

                 }

         }

         public NSArray primaryKeysForNewRowsWithEntity(int count, EOEntity entity) {

                 NSDictionary[] keys = new NSDictionary[count];

                 for (int i = 0; i < count; i++)

                         keys[i] = NSDictionary.EmptyDictionary;

                 return new NSArray(keys);

         }

         public void updateValuesInRowDescribedByQualifier(NSDictionary row, EOQualifier q, EOEntity entity) {

                 adaptorContext().beginTransaction();

                 int count = updateValuesInRowsDescribedByQualifier(row, q, entity);

                 if (count != 1) {

                         adaptorContext().rollbackTransaction();

                         throw new EOGeneralAdaptorException("The qualifier should describe exactly one row (updated " + count + " rows)");

                 }

                 adaptorContext().commitTransaction();

         }

 }

 /*

  * $Log$

  * Revision 1.2  2006/02/16 16:47:14  cgruber

  * Move some classes in to "internal" packages and re-work imports, etc.

  *

  * Also use UnsupportedOperationExceptions where appropriate, instead of WotonomyExceptions.

  *

  * Revision 1.1  2006/02/16 13:19:57  cgruber

  * Check in all sources in eclipse-friendly maven-enabled packages.

  *

  * Revision 1.2  2005/05/11 15:21:53  cgruber

  * Change enum to enumeration, since enum is now a keyword as of Java 5.0

  *

  * A few other comments in the code.

  *

  * Revision 1.1  2003/08/13 00:37:45  chochos

  * an almost complete implementation of the abstract adaptor-layer classes

  *

  */