GUACAMOLE-5: Define Shareable interface which defines a mechanism for generating (likely temporary) credentials.

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

@@ -0,0 +1,63 @@
+/*
+ * 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 org.apache.guacamole.GuacamoleException;
+import org.apache.guacamole.net.auth.credentials.UserCredentials;
+
+/**
+ * An object which can be shared with others via specially-generated sets of
+ * credentials. It is expected, but not required, that these credentials are
+ * temporary.
+ *
+ * @param <T>
+ *     The type of object which dictates the semantics/restrictions of shared
+ *     objects.
+ *
+ * @author Michael Jumper
+ */
+public interface Shareable<T> {
+
+    /**
+     * Returns a full set of credentials which can be used to authenticate as a
+     * user with access strictly to this object. The semantics and restrictions
+     * of the shared object (when accessed using the returned sharing
+     * credentials) are defined by the {@link T} associated with the given
+     * identifier and within the
+     * {@link Directory}&lt;{@link T}&gt; of the same {@link UserContext} that
+     * this Shareable was retrieved from.
+     *
+     * @param identifier
+     *     The identifier of a {@link T} within the
+     *     {@link Directory}&lt;{@link T}&gt; of the same {@link UserContext}
+     *     that this Shareable was retrieved from.
+     *
+     * @return
+     *     A full set of credentials which can be used to authenticate and
+     *     obtain access to this object.
+     *
+     * @throws GuacamoleException
+     *     If credentials could not be generated, or permission to share this
+     *     object is denied.
+     */
+    public UserCredentials getSharingCredentials(String identifier)
+            throws GuacamoleException;
+
+}