GUACAMOLE-96: Add convenience class for decorating the objects returned by a Directory.

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;
+
+        return decorate(object);
+    }
+
+    @Override
+    public Collection<ObjectType> getAll(Collection<String> identifiers)
+            throws GuacamoleException {
+
+        Collection<ObjectType> objects = super.getAll(identifiers);
+
+        // Decorate all retrieved objects, if any
+        Collection<ObjectType> decorated = new ArrayList<ObjectType>(objects.size());
+        for (ObjectType object : objects)
+            decorated.add(decorate(object));
+
+        return decorated;
+
+    }
+
+    @Override
+    public void add(ObjectType object) throws GuacamoleException {
+        super.add(undecorate(object));
+    }
+
+    @Override
+    public void update(ObjectType object) throws GuacamoleException {
+        super.update(undecorate(object));
+    }
+
+}

guacamole-ext/src/main/java/org/apache/guacamole/net/auth/DelegatingDirectory.java

@@ -0,0 +1,83 @@
+/*
+ * 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.Collection;
+import java.util.Set;
+import org.apache.guacamole.GuacamoleException;
+
+/**
+ * Directory implementation which simply delegates all function calls to an
+ * underlying Directory.
+ *
+ * @param <ObjectType>
+ *     The type of objects stored within this Directory.
+ */
+public class DelegatingDirectory<ObjectType extends Identifiable>
+        implements Directory<ObjectType> {
+
+    /**
+     * The wrapped Directory.
+     */
+    private final Directory<ObjectType> directory;
+
+    /**
+     * Wraps the given Directory such that all function calls against this
+     * DelegatingDirectory will be delegated to it.
+     *
+     * @param directory
+     *     The directory to wrap.
+     */
+    public DelegatingDirectory(Directory<ObjectType> directory) {
+        this.directory = directory;
+    }
+
+    @Override
+    public ObjectType get(String identifier) throws GuacamoleException {
+        return directory.get(identifier);
+    }
+
+    @Override
+    public Collection<ObjectType> getAll(Collection<String> identifiers)
+            throws GuacamoleException {
+        return directory.getAll(identifiers);
+    }
+
+    @Override
+    public Set<String> getIdentifiers() throws GuacamoleException {
+        return directory.getIdentifiers();
+    }
+
+    @Override
+    public void add(ObjectType object) throws GuacamoleException {
+        directory.add(object);
+    }
+
+    @Override
+    public void update(ObjectType object) throws GuacamoleException {
+        directory.update(object);
+    }
+
+    @Override
+    public void remove(String identifier) throws GuacamoleException {
+        directory.remove(identifier);
+    }
+
+}