GUAC-1100: Implement recursive BFS tree retrieval.

guacamole/src/main/java/org/glyptodon/guacamole/net/basic/rest/connectiongroup/ConnectionGroupTree.java

@@ -22,10 +22,19 @@
 
 package org.glyptodon.guacamole.net.basic.rest.connectiongroup;
 
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.HashMap;
 import java.util.List;
+import java.util.Map;
 import org.glyptodon.guacamole.GuacamoleException;
+import org.glyptodon.guacamole.net.auth.Connection;
 import org.glyptodon.guacamole.net.auth.ConnectionGroup;
 import org.glyptodon.guacamole.net.auth.permission.ObjectPermission;
+import org.glyptodon.guacamole.net.basic.rest.connection.APIConnection;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 
 /**
  * Provides access to the entire tree of connection groups and their
@@ -35,11 +44,155 @@ import org.glyptodon.guacamole.net.auth.permission.ObjectPermission;
  */
 public class ConnectionGroupTree {
 
+    /**
+     * Logger for this class.
+     */
+    private static final Logger logger = LoggerFactory.getLogger(ConnectionGroupTree.class);
+    
     /**
      * The root connection group.
      */
-    private final APIConnectionGroup root;
+    private final ConnectionGroup root;
+    
+    /**
+     * The root connection group as an APIConnectionGroup.
+     */
+    private final APIConnectionGroup rootAPIGroup;
 
+    /**
+     * All connection groups that have been retrieved, stored by their
+     * identifiers.
+     */
+    private final Map<String, APIConnectionGroup> retrievedGroups =
+            new HashMap<String, APIConnectionGroup>();
+
+    /**
+     * Adds each of the provided connections to the current tree as children
+     * of their respective parents. The parent connection groups must already
+     * be added.
+     *
+     * @param connections
+     *     The connections to add to the tree.
+     * 
+     * @throws GuacamoleException
+     *     If an error occurs while adding the connection to the tree.
+     */
+    private void addConnections(Collection<Connection> connections)
+        throws GuacamoleException {
+
+        // Add each connection to the tree
+        for (Connection connection : connections) {
+
+            // Retrieve the connection's parent group
+            APIConnectionGroup parent = retrievedGroups.get(connection.getParentIdentifier());
+            if (parent != null) {
+
+                Collection<APIConnection> children = parent.getChildConnections();
+                
+                // Create child collection if it does not yet exist
+                if (children == null) {
+                    children = new ArrayList<APIConnection>();
+                    parent.setChildConnections(children);
+                }
+
+                // Add child
+                children.add(new APIConnection(connection));
+                
+            }
+
+            // Warn of internal consistency issues
+            else
+                logger.debug("Connection \"{}\" cannot be added to the tree: parent \"{}\" does not actually exist.",
+                        connection.getIdentifier(),
+                        connection.getParentIdentifier());
+
+        } // end for each connection
+        
+    }
+    
+    /**
+     * Adds each of the provided connection groups to the current tree as
+     * children of their respective parents. The parent connection groups must
+     * already be added.
+     *
+     * @param connectionGroups
+     *     The connection groups to add to the tree.
+     */
+    private void addConnectionGroups(Collection<ConnectionGroup> connectionGroups) {
+
+        // Add each connection group to the tree
+        for (ConnectionGroup connectionGroup : connectionGroups) {
+
+            // Retrieve the connection group's parent group
+            APIConnectionGroup parent = retrievedGroups.get(connectionGroup.getParentIdentifier());
+            if (parent != null) {
+
+                Collection<APIConnectionGroup> children = parent.getChildConnectionGroups();
+                
+                // Create child collection if it does not yet exist
+                if (children == null) {
+                    children = new ArrayList<APIConnectionGroup>();
+                    parent.setChildConnectionGroups(children);
+                }
+
+                // Add child
+                APIConnectionGroup apiConnectionGroup = new APIConnectionGroup(connectionGroup);
+                retrievedGroups.put(connectionGroup.getIdentifier(), apiConnectionGroup);
+                children.add(apiConnectionGroup);
+                
+            }
+
+            // Warn of internal consistency issues
+            else
+                logger.debug("Connection group \"{}\" cannot be added to the tree: parent \"{}\" does not actually exist.",
+                        connectionGroup.getIdentifier(),
+                        connectionGroup.getParentIdentifier());
+
+        } // end for each connection group
+        
+    }
+    
+    /**
+     * Adds all descendants of the given parent groups to their corresponding
+     * parents already stored under root.
+     *
+     * @param parents
+     *     The parents whose descendants should be added to the tree.
+     *
+     * @throws GuacamoleException
+     *     If an error occurs while retrieving the descendants.
+     */
+    private void addDescendants(Collection<ConnectionGroup> parents)
+        throws GuacamoleException {
+
+        // If no parents, nothing to do
+        if (parents.isEmpty())
+            return;
+
+        Collection<String> childConnectionIdentifiers = new ArrayList<String>();
+        Collection<String> childConnectionGroupIdentifiers = new ArrayList<String>();
+        
+        // Build lists of identifiers for retrieval
+        for (ConnectionGroup parent : parents) {
+            childConnectionIdentifiers.addAll(parent.getConnectionDirectory().getIdentifiers());
+            childConnectionGroupIdentifiers.addAll(parent.getConnectionGroupDirectory().getIdentifiers());
+        }
+
+        // Retrieve child connections
+        if (!childConnectionIdentifiers.isEmpty()) {
+            Collection<Connection> childConnections = root.getConnectionDirectory().getAll(childConnectionIdentifiers);
+            addConnections(childConnections);
+        }
+
+        // Retrieve child connection groups
+        if (!childConnectionGroupIdentifiers.isEmpty()) {
+            Collection<ConnectionGroup> childConnectionGroups = root.getConnectionGroupDirectory().getAll(childConnectionGroupIdentifiers);
+            addConnectionGroups(childConnectionGroups);
+            addDescendants(childConnectionGroups);
+        }
+
+    }
+    
     /**
      * Creates a new connection group tree using the given connection group as
      * the tree root.
@@ -62,9 +215,12 @@ public class ConnectionGroupTree {
             List<ObjectPermission.Type> permissions) throws GuacamoleException {
 
         // Store root of tree
-        this.root = new APIConnectionGroup(root);
+        this.root = root;
+        this.rootAPIGroup = new APIConnectionGroup(root);
+        retrievedGroups.put(root.getIdentifier(), this.rootAPIGroup);
 
-        // STUB
+        // Add all descendants
+        addDescendants(Collections.singleton(root));
         
     }
 
@@ -78,7 +234,7 @@ public class ConnectionGroupTree {
      *     tree and all connections.
      */
     public APIConnectionGroup getRootAPIConnectionGroup() {
-        return root;
+        return rootAPIGroup;
     }
 
 }