Github user mike-jumper commented on a diff in the pull request:
https://github.com/apache/guacamole-client/pull/225#discussion_r162236186
--- Diff:
guacamole-ext/src/main/java/org/apache/guacamole/net/auth/DecoratingDirectory.java
---
@@ -0,0 +1,133 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements. See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership. The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied. See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+package org.apache.guacamole.net.auth;
+
+import java.util.ArrayList;
+import java.util.Collection;
+import org.apache.guacamole.GuacamoleException;
+
+/**
+ * Directory implementation which simplifies decorating the objects within
an
+ * underlying Directory. The decorate() and undecorate() functions must be
+ * implemented to define how each object is decorated, and how that
decoration
+ * may be removed.
+ *
+ * @param <ObjectType>
+ * The type of objects stored within this Directory.
+ */
+public abstract class DecoratingDirectory<ObjectType extends Identifiable>
+ extends DelegatingDirectory<ObjectType> {
+
+ /**
+ * Creates a new DecoratingDirectory which decorates the objects within
+ * the given directory.
+ *
+ * @param directory
+ * The Directory whose objects are being decorated.
+ */
+ public DecoratingDirectory(Directory<ObjectType> directory) {
+ super(directory);
+ }
+
+ /**
+ * Given an object retrieved from a Directory which originates from a
+ * different AuthenticationProvider, returns an identical type of
object
+ * optionally wrapped with additional information, functionality, etc.
If
+ * this directory chooses to decorate the object provided, it is up to
the
+ * implementation of that decorated object to properly pass through
+ * operations as appropriate, as well as provide for an eventual
+ * undecorate() operation. All objects retrieved from this
+ * DecoratingDirectory will first be passed through this function.
+ *
+ * @param object
+ * An object from a Directory which originates from a different
+ * AuthenticationProvider.
+ *
+ * @return
+ * An object which may have been decorated by this
+ * DecoratingDirectory. If the object was not decorated, the
original,
+ * unmodified object may be returned instead.
+ *
+ * @throws GuacamoleException
+ * If the provided object cannot be decorated due to an error.
+ */
+ protected abstract ObjectType decorate(ObjectType object)
+ throws GuacamoleException;
+
+ /**
+ * Given an object originally returned from a call to this
+ * DecoratingDirectory's decorate() function, reverses the decoration
+ * operation, returning the original object. This function is
effectively
+ * the exact inverse of the decorate() function. The return value of
+ * undecorate(decorate(X)) must be identically X. All objects given to
this
+ * DecoratingDirectory via add() or update() will first be passed
through
+ * this function.
+ *
+ * @param object
+ * An object which was originally returned by a call to this
+ * DecoratingDirectory's decorate() function.
+ *
+ * @return
+ * The original object which was provided to this
DecoratingDirectory's
+ * decorate() function.
+ *
+ * @throws GuacamoleException
+ * If the provided object cannot be undecorated due to an error.
+ */
+ protected abstract ObjectType undecorate(ObjectType object)
+ throws GuacamoleException;
+
+ @Override
+ public ObjectType get(String identifier) throws GuacamoleException {
+
+ // Decorate only if object exists
+ ObjectType object = super.get(identifier);
+ if (object == null)
+ return object;
+
--- End diff --
Yeah, that's a fair point. I'll change this to `return null`.
---
