From aedc34d55462a75e329bbf342251ff6504cd117e Mon Sep 17 00:00:00 2001 From: Benjamin Culkin Date: Sun, 19 May 2024 17:56:33 -0400 Subject: Initial import from SVN --- .../java/net/wotonomy/control/EODataSource.java | 164 +++++++++++++++++++++ 1 file changed, 164 insertions(+) create mode 100644 projects/net.wotonomy.persistence/src/main/java/net/wotonomy/control/EODataSource.java (limited to 'projects/net.wotonomy.persistence/src/main/java/net/wotonomy/control/EODataSource.java') diff --git a/projects/net.wotonomy.persistence/src/main/java/net/wotonomy/control/EODataSource.java b/projects/net.wotonomy.persistence/src/main/java/net/wotonomy/control/EODataSource.java new file mode 100644 index 0000000..c7e5284 --- /dev/null +++ b/projects/net.wotonomy.persistence/src/main/java/net/wotonomy/control/EODataSource.java @@ -0,0 +1,164 @@ +/* +Wotonomy: OpenStep design patterns for pure Java applications. +Copyright (C) 2000 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 net.wotonomy.foundation.NSArray; + +/** +* EODataSource is used by EODisplayGroup.fetch() to retrieve +* a list of objects to display. When a display group has a +* data source, the display group will use the data source to +* populate the object list and to create new objects to be +* displayed in the list, and will update the data source when +* objects are inserted or removed from the list.

+* +* In certain cases, as when a display group needs to populate +* a child display group to show a one-to-many relationship, +* the display group will call dataSourceQualifiedByKey to +* return a new data source that can vend objects associated +* with the specified key and then call qualifyWithRelationshipKey +* to specify the object and key that are the source of the +* child relationship.

+* +* Concrete subclasses are expected to override fetch() and +* are required to override insertObject and removeObject. +* +* @author michael@mpowers.net +* @author $Author: cgruber $ +* @version $Revision: 894 $ +*/ +public abstract class EODataSource +{ + /** + * Creates a new object. You should call + * insertObject() to insert the new object into + * this data source. + * This implementation attempts to create a new + * instance of the class returned by + * classDescriptionForObjects(). + * Override to return an object specific to + * your implementation. + * @return The newly created object, or null if + * new objects are not supported by this data source. + * @see #classDescriptionForObjects + */ + public Object createObject () + { + Object result = null; + EOClassDescription c = classDescriptionForObjects(); + if ( c != null ) + { + result = c.createInstanceWithEditingContext( editingContext(), null ); + } + return result; + } + + /** + * Inserts the specified object into this data source. + */ + public abstract void insertObject ( Object anObject ); + + /** + * Deletes the specified object from this data source. + */ + public abstract void deleteObject ( Object anObject ); + + /** + * Returns the editing context for this data source, + * or null if no editing context is used. + * This implementation returns null. + */ + public EOEditingContext editingContext () + { + return null; + } + + /** + * Returns a List containing the objects in this + * data source. This implementation returns null. + */ + public NSArray fetchObjects () + { + return null; + } + + /** + * Returns a 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 abstract EODataSource + dataSourceQualifiedByKey ( String aKey ); + + /** + * Restricts this data source to vend those + * objects that are associated with the specified + * key on the specified object. + */ + public abstract void + qualifyWithRelationshipKey ( + String aKey, Object anObject ); + + /** + * Returns the description of the class of the + * objects that is vended by this data source, + * or null if this cannot be determined. + * This implementation returns null. + */ + public EOClassDescription + classDescriptionForObjects () + { + return null; + } + +} + +/* + * $Log$ + * 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 1.5 2001/05/21 14:02:44 mpowers + * Corrected javadoc. + * + * Revision 1.4 2001/04/27 23:37:20 mpowers + * Now using EOClassDescription in the EODataSource class, as we should. + * + * Revision 1.3 2001/02/27 23:11:07 mpowers + * Removed object registration from createObject(). + * + * Revision 1.2 2001/02/16 18:34:19 mpowers + * Implementing nested contexts. + * + * Revision 1.1.1.1 2000/12/21 15:46:38 mpowers + * Contributing wotonomy. + * + * Revision 1.3 2000/12/20 16:25:34 michael + * Added log to all files. + * + * + */ + -- cgit v1.2.3