Added index class which allows to build an index of Nodes stored in a NodeContainer

1 files changed, 117 insertions, 0 deletions

diff --git a/src/core/model/Index.hpp b/src/core/model/Index.hpp
new file mode 100644
index 0000000..18acb6a
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+++ b/src/core/model/Index.hpp
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+/*
+    Ousía
+    Copyright (C) 2014, 2015  Benjamin Paaßen, Andreas Stöckel
+
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+/**
+ * @file Index.hpp
+ *
+ * Contains the Index class which facilitates resolution of Node names.
+ *
+ * @author Andreas Stöckel (astoecke@techfak.uni-bielefeld.de)
+ */
+
+#ifndef _OUSIA_INDEX_HPP_
+#define _OUSIA_INDEX_HPP_
+
+#include <string>
+#include <unordered_map>
+
+#include <core/managed/Managed.hpp>
+
+namespace ousia {
+
+// Forward declarations
+class Node;
+
+/**
+ * The Index class is a listener for NodeContainer instances and automatically 
+ * creates a dictionary for looking up Node instances by name. The Index class
+ * automatically maintains consistency when nodes are added or removed from the
+ * container or the Nodes themself are renamed. It is not a replacement for the  
+ * NodeContainer or ManagedContainer classes, but is used as Listener class 
+ * inside these classes.
+ */
+class Index {
+private:
+	/**
+	 * Map from names to the corresponding nodes.
+	 */
+	std::unordered_map<std::string, Node *> index;
+
+	/**
+	 * Adds a reference to the given node with the given name to the index.
+	 * Empty names are ignored.
+	 *
+	 * @param name is the name under which the element should be found in the
+	 * index. Elements with empty name are ignored. The name must be unique.
+	 * @param node is a reference to the node that should be associated with the
+	 * given name.
+	 */
+	void addToIndex(const std::string &name, const Handle<Node> &node);
+
+	/**
+	 * Deletes a reference to the given node from the index.
+	 *
+	 * @param name is the name under which the element should be found in the
+	 * index. Elements with empty name are ignored. Does nothing if no entry
+	 * with the given name exists.
+	 * @param node is a reference to the node that should be associated with the
+	 * given name.
+	 */
+	void deleteFromIndex(const std::string &name, const Handle<Node> &node);
+
+	/**
+	 * Called automatically whenever the name of a node in the index changes.
+	 *
+	 * @param ev contain the NameChangeEvent data.
+	 * @param owner is the Managed object that owns the node for which the event
+	 * handler was registered.
+	 * @param data contains the reference to the Index instance.
+	 */
+	static void indexHandleNameChange(const Event &ev, Managed *owner,
+	                                  void *data);
+
+public:
+	/**
+	 * Adds an element to the index. Called by the ManagedContainer class.
+	 *
+	 * @param val is a reference to the node instance that should be indexed.
+	 * @param owner is the Managed object that owns the given node.
+	 */
+	void addElement(Handle<Node> node, Managed *owner);
+
+	/**
+	 * Removes an element from the index. Called by the ManagedContainer class.
+	 *
+	 * @param val is a reference to the node instance that should be indexed.
+	 * @param owner is the Managed object that owns the given node.
+	 * @param fromDestructor set to true, if the function is called from the
+	 * ManagedContainer destructor and the node may no longer be valid.
+	 */
+	void deleteElement(Handle<Node> node, Managed *owner, bool fromDestructor);
+
+	/**
+	 * Resolves the given name to a reference to a node with this name or to
+	 * nullptr if such a node does not exist.
+	 */
+	Rooted<Node> resolve(const std::string &name) const;
+};
+
+}
+
+#endif /* _OUSIA_INDEX_HPP_ */
+