/*
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.control;

import java.util.Collection;
import java.util.Map;

import net.wotonomy.foundation.NSArray;
import net.wotonomy.foundation.NSDictionary;
import net.wotonomy.foundation.NSMutableArray;
import net.wotonomy.foundation.NSSet;
import net.wotonomy.foundation.internal.WotonomyException;

/**
 * EODatabaseSource is a general-purpose implementation of EODataSource that is
 * EOClassDescription-aware and that can vend appropriate EODetailDataSources.
 *
 * @author michael@mpowers.net
 * @author $Author: cgruber $
 * @version $Revision: 894 $
 */
public abstract class EODatabaseDataSource {
	EOQualifier auxiliaryQualifier;
	EOEditingContext editingContext;
	String entityName;
	String fetchSpecificationName;
	EOFetchSpecification fetchSpecification;
	NSDictionary qualifierBindings;
	EOClassDescription classDescription;
	boolean fetchEnabled;

	/**
	 * Constructs a data source that fetches all objects of the specified entity
	 * type.
	 */
	public EODatabaseDataSource(EOEditingContext aContext, String anEntityName) {
		this(aContext, anEntityName, null);
	}

	/**
	 * Constructs a data source that fetches objects of the specified entity type
	 * according to the fetch specification with the specified name.
	 */
	public EODatabaseDataSource(EOEditingContext aContext, String anEntityName, String aFetchSpecName) {
		fetchEnabled = true;
		editingContext = aContext;
		entityName = anEntityName;
		setFetchSpecificationByName(fetchSpecificationName);
	}

	/**
	 * Returns the qualifier that is applied to the results fetched by the fetch
	 * specification before objects are returned by fetch objects, or null if no
	 * such qualifier has been specified.
	 */
	public EOQualifier auxiliaryQualifier() {
		return auxiliaryQualifier;
	}

	/**
	 * Returns the description of the class of the objects that is vended by this
	 * data source, or null if no entity name is specified.
	 */
	public EOClassDescription classDescriptionForObjects() {
		if (entityName == null)
			return null;
		return EOClassDescription.classDescriptionForEntityName(entityName);
	}

	/**
	 * Returns the object store at the root of the editing context's editing
	 * hierarchy.
	 */
	public EOObjectStore databaseContext() {
		EOObjectStore store = editingContext();
		while (store instanceof EOEditingContext) {
			store = ((EOEditingContext) store).parentObjectStore();
		}
		return store;
	}

	/**
	 * Returns a detail data source that is capable of manipulating objects of the
	 * type returned by applying the specified key to objects vended by this data
	 * source.
	 * 
	 * @see #qualifyWithRelationshipKey
	 */
	public EODataSource dataSourceQualifiedByKey(String aKey) {
		throw new WotonomyException("Not implemented yet.");
	}

	/**
	 * Deletes the specified object from this data source. This implementation
	 * deletes the specified object from the editing context.
	 */
	public void deleteObject(Object anObject) {
		editingContext.deleteObject(anObject);
	}

	/**
	 * Returns the editing context for this data source, or null if no editing
	 * context was specified.
	 */
	public EOEditingContext editingContext() {
		return editingContext;
	}

	/*
	 * public EOEntity entity() {}
	 */

	/**
	 * Returns a List containing the objects of the current entity type that conform
	 * to the specified fetch specification. If an auxiliary qualifier has been
	 * specified, that qualifier is applied to the objects before returning the
	 * result. If fetch is not enabled, this method returns null.
	 */
	public NSArray fetchObjects() {
		if (!isFetchEnabled())
			return null;
		NSArray result = editingContext.objectsWithFetchSpecification(fetchSpecification());
		if (auxiliaryQualifier() != null) {
			result = EOQualifier.filteredArrayWithQualifier(result, auxiliaryQualifier());
		}
		return result;
	}

	/**
	 * Returns the fetch specification currently used by this data source to fetch
	 * objects, or null if none is specified. If null, this fetchObjects() will
	 * return all objects of the specified entity type.
	 */
	public EOFetchSpecification fetchSpecification() {
		return fetchSpecification;
	}

	/**
	 * Returns a copy of the fetch specification that will be used to determine
	 * fetch for this data source. If this data source has an auxiliary qualifier,
	 * that qualifier will be inserted into the returned fetch specification's
	 * qualifier.
	 */
	public EOFetchSpecification fetchSpecificationForFetch() {
		EOFetchSpecification result = (EOFetchSpecification) fetchSpecification.clone();
		if (auxiliaryQualifier() != null) {
			NSMutableArray join = new NSMutableArray();
			join.addObject(fetchSpecification.qualifier());
			join.addObject(auxiliaryQualifier());
			result.setQualifier(new EOAndQualifier(join));
		}
		return result;
	}

	/**
	 * Returns the name of the current fetch specification, or null if no name has
	 * been specified.
	 */
	public String fetchSpecificationName() {
		return fetchSpecificationName;
	}

	/**
	 * Inserts the specified object into this data source. This implementation
	 * registers the object as an inserted object with the editing context.
	 */
	public void insertObject(Object anObject) {
		editingContext.insertObject(anObject);
	}

	/**
	 * Returns whether fetching is currently allowed. If false, fetchObjects() will
	 * return null. Default is true.
	 */
	public boolean isFetchEnabled() {
		return fetchEnabled;
	}

	/**
	 * Returns a List of the union of the binding keys for the fetch spec's
	 * qualifier and the auxiliary qualifier.
	 */
	public NSArray qualifierBindingKeys() {
		NSSet union = new NSSet();
		if ((fetchSpecification != null) && (fetchSpecification.qualifier() != null)) {
			union.addAll(fetchSpecification.qualifier().bindingKeys());
		}
		if (auxiliaryQualifier() != null) {
			union.addAll(auxiliaryQualifier().bindingKeys());
		}
		return new NSArray((Collection) union);
	}

	/**
	 * Returns a Map of the bindings that will be applied against the fetch spec's
	 * qualifier and the auxiliary qualifier, or null if no bindings exist.
	 */
	public NSDictionary qualifierBindings() {
		if (qualifierBindings == null)
			return null;
		return new NSDictionary((Map) qualifierBindings);
	}

	/**
	 * Restricts this data source to vend those objects that are associated with the
	 * specified key on the specified object.
	 */
	public void qualifyWithRelationshipKey(String aKey, Object anObject) {
		throw new WotonomyException("Not implemented yet");
	}

	/**
	 * Sets the auxiliary qualifier that will be applied to objects returned from
	 * the fetch described by the fetch specification.
	 */
	public void setAuxiliaryQualifier(EOQualifier aQualifier) {
		auxiliaryQualifier = aQualifier;
	}

	/**
	 * Sets whether fetches are currently allowed. If false, fetchObjects() will
	 * return null.
	 */
	public void setFetchEnabled(boolean isFetchEnabled) {
		fetchEnabled = isFetchEnabled;
	}

	/**
	 * Sets the fetch specification used by this data source. If null, all objects
	 * of the specified entity type will be returned by fetchObjects().
	 */
	public void setFetchSpecification(EOFetchSpecification aFetchSpec) {
		fetchSpecificationName = null;
		fetchSpecification = aFetchSpec;
	}

	/**
	 * Sets the fetch specification used by this data source, requesting it from the
	 * class description for this data source's entity class description, if any. If
	 * the name cannot be resolved, the fetch specification will be set to null.
	 */
	public void setFetchSpecificationByName(String aName) {
		fetchSpecificationName = aName;
		fetchSpecification = EOFetchSpecification.fetchSpecificationNamed(aName, entityName);
	}

	/*
	 * public void setParentDataSourceRelationshipKey( EODataSource aDataSource,
	 * String aKey)
	 */

	/**
	 * Sets the bindings to be applied to the fetch specification and the auxiliary
	 * qualifier.
	 */
	public void setQualifierBindings(Map aBindingMap) {
		if (aBindingMap == null) {
			qualifierBindings = null;
		} else {
			qualifierBindings = new NSDictionary((Map) aBindingMap);
		}
	}
}

/*
 * $Log$ 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 1.1 2001/11/24 17:38:00 mpowers Contributing EODatabaseDataSource.
 *
 *
 */