Changeset 4 for trunk

Timestamp:

08/12/2005 07:01:46 PM (21 years ago)

Author:

dsowen

Message:

Feature: can automatically fill missing parts of a graph.

Location:

trunk

Files:

• src/ws/fugue88/jpath/BrokenGraphException.java (added)
• src/ws/fugue88/jpath/Context.java (modified) (5 diffs)
• src/ws/fugue88/jpath/ContextFactory.java (modified) (2 diffs)
• testsrc/ws/fugue88/jpath/ContextTest.java (modified) (2 diffs)

trunk/src/ws/fugue88/jpath/Context.java

@@ -3 +3 @@
  *
  * $Log$
+ * Revision 1.2  2005/08/12 19:01:46  dsowen
+ * Feature: can automatically fill missing parts of a graph.
+ *
  * Revision 1.1  2005/08/03 00:35:29  dsowen
  * Initial commit.
@@ -26 +29 @@
 
         public Accessor getTargetAccessor(final Path path)
-                        throws InvocationTargetException, NoSuchPropertyException
+                        throws BrokenGraphException, IllegalAccessException,
+                        InstantiationException, InvocationTargetException,
+                        NoSuchPropertyException
         {
                 Context current = this;
@@ -32 +37 @@
                 for(Iterator i = path.iterator(); i.hasNext();) {
                         accessor = current.getTargetAccessor((PathPart)i.next());
-                        current = new Context(accessor.getValue(), _binder);
+                        Object obj = accessor.getValue();
+                        if(obj == null) {
+                                if(_modifying && i.hasNext()) {
+                                        obj = createBlank(accessor.getType());
+                                        accessor.setValue(obj);
+                                } else {
+                                        throw new BrokenGraphException();
+                                }
+                        }
+                        current = new Context(obj, _binder, _modifying);
                 }
                 return accessor;
         }
 
-        public Object getTarget(final Path path) throws InvocationTargetException,
+        public Object getTarget(final Path path) throws IllegalAccessException,
+                        InstantiationException, InvocationTargetException,
                         NoSuchPropertyException
         {
-                return getTargetAccessor(path).getValue();
+                try {
+                        return getTargetAccessor(path).getValue();
+                } catch(BrokenGraphException e) {
+                        return null;
+                }
         }
 
-        public Context navigate(final Path path) throws InvocationTargetException,
+        public Context navigate(final Path path) throws IllegalAccessException,
+                        InstantiationException, InvocationTargetException,
                         NoSuchPropertyException
         {
                 Object child = getTarget(path);
-                return new Context(child, _binder);
+                return new Context(child, _binder, _modifying);
         }
 
@@ -55 +75 @@
         }
 
-        Context(final Object root, final Binder binder)
+        Context(final Object root, final Binder binder, final boolean modifying)
         {
+                // NPEs
+                root.getClass();
+                binder.getClass();
+
                 _root = root;
                 _binder = binder;
+                _modifying = modifying;
         }
 
@@ -83 +108 @@
         }
 
+        private Object createBlank(final Class type) throws IllegalAccessException,
+                        InstantiationException
+        {
+                return type.newInstance();
+        }
+
         private final Object _root;
         private final Binder _binder;
+        private final boolean _modifying;
 }

trunk/src/ws/fugue88/jpath/ContextFactory.java

@@ -3 +3 @@
  * 
  * $Log$
+ * Revision 1.2  2005/08/12 19:01:46  dsowen
+ * Feature: can automatically fill missing parts of a graph.
+ *
  * Revision 1.1  2005/08/03 00:35:29  dsowen
  * Initial commit.
@@ -16 +19 @@
         public Context createContext(final Object root)
         {
-                return new Context(root, _binder);
+                return new Context(root, _binder, false);
+        }
+
+        public Context createModifyingContext(final Object root)
+        {
+                return new Context(root, _binder, true);
         }
 

trunk/testsrc/ws/fugue88/jpath/ContextTest.java

@@ -3 +3 @@
  * 
  * $Log$
+ * Revision 1.2  2005/08/12 19:01:46  dsowen
+ * Feature: can automatically fill missing parts of a graph.
+ *
  * Revision 1.1  2005/08/03 00:35:29  dsowen
  * Initial commit.
@@ -101 +104 @@
                 assertEquals("done", a.b.get("c"));
         }
+
+        public void testEarlyNull() throws Exception
+        {
+                class A {
+
+                        String s;
+                }
+                class B {
+
+                        A a;
+                }
+                B b = new B();
+
+                ContextFactory factory = new ContextFactory();
+                Context context = factory.createContext(b);
+                assertNull(context.getTarget(new Path("/a/s")));
+                assertNull(b.a);
+        }
+
+        static class A {
+
+                String s;
+        }
+
+        public void testAutoGraph() throws Exception
+        {
+                class B {
+
+                        A a;
+                }
+                B b = new B();
+
+                ContextFactory factory = new ContextFactory();
+                Context context = factory.createModifyingContext(b);
+                assertNull(context.getTarget(new Path("/a/s")));
+                assertNotNull(b.a);
+                assertNull(b.a.s);
+        }
 }