1 files changed, 164 insertions, 0 deletions
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. <br><br>
+*
+* 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. <br><br>
+*
+* 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.
+ *
+ *
+ */
+