GUACAMOLE-926: Create directory infrastructure for batch creation.

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

@@ -0,0 +1,57 @@
+/*
+ * 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;
+
+/**
+ * An operation that should be attempted atomically when passed to
+ * {@link Directory#tryAtomically()}, if atomic operations are supported by
+ * the Directory.
+ */
+public interface AtomicDirectoryOperation<ObjectType extends Identifiable>  {
+
+    /**
+     * Attempt the operation atomically. If the Directory does not support
+     * atomic operations, the atomic flag will be set to false. If the atomic
+     * flag is set to true, the provided directory is guaranteed to perform
+     * the operations within this function atomically. Atomicity of the
+     * provided directory outside this function, or of the directory invoking
+     * this function are not guaranteed.
+     *
+     * NOTE: If atomicity is required for this operation, a GuacamoleException
+     * may be thrown by this function before any changes are made, ensuring the
+     * operation will only ever be performed atomically.
+     *
+     * @param atomic
+     *     True if the provided directory is guaranteed to peform the operation
+     *     atomically within the context of this function.
+     *
+     * @param directory
+     *     A directory that will perform the operation atomically if the atomic
+     *     flag is set to true. If the flag is false, the directory may still
+     *     be used, though atomicity is not guaranteed.
+     *
+     * @throws GuacamoleException
+     *     If an issue occurs during the operation.
+     */
+    void executeOperation(boolean atomic, Directory<ObjectType> directory)
+            throws GuacamoleException;
+}

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

@@ -20,6 +20,7 @@
 package org.apache.guacamole.net.auth;
 
 import java.util.Collection;
+import java.util.Iterator;
 import java.util.Set;
 import org.apache.guacamole.GuacamoleException;
 
@@ -198,6 +199,29 @@ public interface Directory<ObjectType extends Identifiable> {
     void add(ObjectType object)
             throws GuacamoleException;
 
+    /**
+     * Adds the given objects to the overall set. If new identifiers are
+     * created for any of the the added objects, the identifiers will be
+     * automatically assigned via setIdentifier().
+     *
+     * @param objects
+     *     The objects to add.
+     *
+     * @throws GuacamoleException
+     *     If an error occurs while adding any of the objects, or if adding
+     *     the objects is not allowed.
+     */
+    default void add(Collection<ObjectType> objects)
+            throws GuacamoleException {
+
+        // Add each object individually by default
+        Iterator<ObjectType> iterator = objects.iterator();
+        while (iterator.hasNext()) {
+            add(iterator.next());
+        }
+
+    }
+
     /**
      * Updates the stored object with the data contained in the given object.
      *
@@ -209,14 +233,73 @@ public interface Directory<ObjectType extends Identifiable> {
     void update(ObjectType object)
             throws GuacamoleException;
 
+    /**
+     * Updates the stored objects with the data contained in the given objects.
+     *
+     * @param objects The objects which will supply the data for the update.
+     *
+     * @throws GuacamoleException If an error occurs while updating the objects,
+     *                            or if updating an object is not allowed.
+     */
+    default void update(Collection<ObjectType> objects)
+            throws GuacamoleException {
+
+        // Update each object individually by default
+        Iterator<ObjectType> iterator = objects.iterator();
+        while (iterator.hasNext()) {
+            update(iterator.next());
+        }
+
+    }
+
     /**
      * Removes the object with the given identifier from the overall set.
      *
      * @param identifier The identifier of the object to remove.
      *
      * @throws GuacamoleException If an error occurs while removing the object,
-     *                            or if removing object is not allowed.
+     *                            or if removing the object is not allowed.
      */
     void remove(String identifier) throws GuacamoleException;
 
+    /**
+     * Removes all object with any of the given identifier from the overall set.
+     *
+     * @param identifiers The identifiers of the objects to remove.
+     *
+     * @throws GuacamoleException If an error occurs while removing an object,
+     *                            or if removing an object is not allowed.
+     */
+    default void remove(Collection<String> identifiers)
+            throws GuacamoleException {
+
+        // Remove each object individually by default
+        Iterator<String> iterator = identifiers.iterator();
+        while (iterator.hasNext()) {
+            remove(iterator.next());
+        }
+
+    }
+
+    /**
+     * Attempt to perform the provided operation atomically if possible. If the
+     * operation can be performed atomically, the atomic flag will be set to
+     * true, and the directory passed to the provided operation callback will
+     * peform directory operations atomically within the operation callback.
+     *
+     * @param operation
+     *     The directory operation that should be performed atomically.
+     *
+     * @throws GuacamoleException
+     *     If an error occurs during execution of the provided operation.
+     */
+    default void tryAtomically(AtomicDirectoryOperation<ObjectType> operation)
+            throws GuacamoleException {
+
+        // By default, perform the operation non-atomically. If atomic operation
+        // is supported by an implementation, it must be implemented there.
+        operation.executeOperation(false, this);
+
+    }
+
 }