/*
 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
 *
 */