/*
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.
 *
 *
 */