Class InMemoryNodeModel

  • All Implemented Interfaces:
    NodeModel<ImmutableNode>

    public class InMemoryNodeModel
    extends java.lang.Object
    implements NodeModel<ImmutableNode>

    A specialized node model implementation which operates on ImmutableNode structures.

    This NodeModel implementation keeps all its data as a tree of ImmutableNode objects in memory. The managed structure can be manipulated in a thread-safe, non-blocking way. This is achieved by using atomic variables: The root of the tree is stored in an atomic reference variable. Each update operation causes a new structure to be constructed (which reuses as much from the original structure as possible). The old root node is then replaced by the new one using an atomic compare-and-set operation. If this fails, the manipulation has to be done anew on the updated structure.

    Since:
    2.0
    • Field Detail

      • DUMMY_HANDLER

        private static final NodeHandler<ImmutableNode> DUMMY_HANDLER
        A dummy node handler instance used in operations which require only a limited functionality.
      • structure

        private final java.util.concurrent.atomic.AtomicReference<TreeData> structure
        Stores information about the current nodes structure.
    • Constructor Detail

      • InMemoryNodeModel

        public InMemoryNodeModel()
        Creates a new instance of InMemoryNodeModel which is initialized with an empty root node.
      • InMemoryNodeModel

        public InMemoryNodeModel​(ImmutableNode root)
        Creates a new instance of InMemoryNodeModel and initializes it from the given root node. If the passed in node is null, a new, empty root node is created.
        Parameters:
        root - the new root node for this model
    • Method Detail

      • addAttributeProperty

        private static void addAttributeProperty​(ModelTransaction tx,
                                                 NodeAddData<ImmutableNode> addData,
                                                 java.lang.Iterable<?> values)
        Handles an add property operation if the property to be added is an attribute.
        Parameters:
        tx - the transaction
        addData - the NodeAddData
        values - the collection with node values
      • addNodeProperty

        private static void addNodeProperty​(ModelTransaction tx,
                                            NodeAddData<ImmutableNode> addData,
                                            java.lang.Iterable<?> values)
        Handles an add property operation if the property to be added is a node.
        Parameters:
        tx - the transaction
        addData - the NodeAddData
        values - the collection with node values
      • addNodesByAddData

        private static void addNodesByAddData​(ModelTransaction tx,
                                              NodeAddData<ImmutableNode> addData,
                                              java.util.Collection<ImmutableNode> newNodes)
        Initializes a transaction to add a collection of nodes as described by a NodeAddData object. If necessary, new path nodes are created. Eventually, the new nodes are added as children to the specified target node.
        Parameters:
        tx - the transaction
        addData - the NodeAddData
        newNodes - the collection of new child nodes
      • attributeKeyException

        private static java.lang.IllegalArgumentException attributeKeyException​(java.lang.String key)
        Creates an exception referring to an invalid key for adding properties. Such an exception is thrown when an operation tries to add something to an attribute.
        Parameters:
        key - the invalid key causing this exception
        Returns:
        the exception
      • checkIfNodeDefined

        static boolean checkIfNodeDefined​(ImmutableNode node)
        Checks if the passed in node is defined. Result is true if the node contains any data.
        Parameters:
        node - the node in question
        Returns:
        true if the node is defined, false otherwise
      • createDataWithTrackedChildNode

        private static TreeData createDataWithTrackedChildNode​(TreeData current,
                                                               ImmutableNode parent,
                                                               java.lang.String childName,
                                                               NodeKeyResolver<ImmutableNode> resolver,
                                                               org.apache.commons.lang3.mutable.MutableObject<NodeSelector> refSelector)
        Creates a new data object with a tracked child node of the given parent node. If such a child node already exists, it is used. Otherwise, a new one is created.
        Parameters:
        current - the current TreeData object
        parent - the parent node
        childName - the name of the child node
        resolver - the NodeKeyResolver
        refSelector - here the newly created NodeSelector is returned
        Returns:
        the new TreeData instance
      • createNodeOnPath

        private static ImmutableNode createNodeOnPath​(java.util.Iterator<java.lang.String> it,
                                                      java.util.Collection<ImmutableNode> newNodes)
        Recursive helper method for creating a path node for an add operation. All path nodes except for the last have a single child. The last path node has the new nodes as children.
        Parameters:
        it - the iterator over the names of the path nodes
        newNodes - the collection of new child nodes
        Returns:
        the newly created path node
      • createNodesToAdd

        private static java.util.Collection<ImmutableNode> createNodesToAdd​(java.lang.String newNodeName,
                                                                            java.lang.Iterable<?> values)
        Creates a collection with new nodes with a given name and a value from a given collection.
        Parameters:
        newNodeName - the name of the new nodes
        values - the collection with node values
        Returns:
        the newly created collection
      • createNodeToAddWithPath

        private static ImmutableNode createNodeToAddWithPath​(NodeAddData<ImmutableNode> addData,
                                                             java.util.Collection<ImmutableNode> newNodes)
        Creates a node structure consisting of the path nodes defined by the passed in NodeAddData instance and all new child nodes.
        Parameters:
        addData - the NodeAddData
        newNodes - the collection of new child nodes
        Returns:
        the parent node of the newly created hierarchy
      • createSelectorsForTrackedNodes

        private static TreeData createSelectorsForTrackedNodes​(org.apache.commons.lang3.mutable.Mutable<java.util.Collection<NodeSelector>> refSelectors,
                                                               java.util.List<ImmutableNode> nodes,
                                                               TreeData current,
                                                               NodeKeyResolver<ImmutableNode> resolver)
        Creates tracked node entries for the specified nodes and creates the corresponding selectors.
        Parameters:
        refSelectors - the reference where to store the selectors
        nodes - the nodes to be tracked
        current - the current TreeData object
        resolver - the NodeKeyResolver
        Returns:
        the updated TreeData object
      • determineRootName

        private static java.lang.String determineRootName​(ImmutableNode rootNode,
                                                          ImmutableNode node,
                                                          java.lang.String rootName)
        Determines the name of the root node for a merge operation. If a root name is provided, it is used. Otherwise, if the current root node has no name, the name of the node to be merged is used. A result of null means that no node name has to be set.
        Parameters:
        rootNode - the current root node
        node - the node to be merged with the root node
        rootName - the name of the resulting node
        Returns:
        the new name of the root node
      • initializeClearTransaction

        private static boolean initializeClearTransaction​(ModelTransaction tx,
                                                          java.util.Collection<QueryResult<ImmutableNode>> results)
        Initializes a transaction to clear the values of a property based on the passed in collection of affected results.
        Parameters:
        tx - the transaction to be initialized
        results - a collection with results pointing to the nodes to be cleared
        Returns:
        a flag whether there are elements to be cleared
      • initializeUpdateTransaction

        private static boolean initializeUpdateTransaction​(ModelTransaction tx,
                                                           java.util.Map<QueryResult<ImmutableNode>,​java.lang.Object> changedValues)
        Initializes a transaction to change the values of some query results based on the passed in map.
        Parameters:
        tx - the transaction to be initialized
        changedValues - the map defining the elements to be changed
        Returns:
        a flag whether there are elements to be updated
      • initialRootNode

        private static ImmutableNode initialRootNode​(ImmutableNode providedRoot)
        Determines the initial root node of this model. If a root node has been provided, it is used. Otherwise, an empty dummy root node is created.
        Parameters:
        providedRoot - the passed in root node
        Returns:
        the root node to be used
      • updateDataWithNewTrackedNode

        private static TreeData updateDataWithNewTrackedNode​(TreeData current,
                                                             ImmutableNode node,
                                                             NodeKeyResolver<ImmutableNode> resolver,
                                                             org.apache.commons.lang3.mutable.MutableObject<NodeSelector> refSelector)
        Adds a tracked node that has already been resolved to the specified data object.
        Parameters:
        current - the current TreeData object
        node - the node in question
        resolver - the NodeKeyResolver
        refSelector - here the newly created NodeSelector is returned
        Returns:
        the new TreeData instance
      • updateParentMapping

        static void updateParentMapping​(java.util.Map<ImmutableNode,​ImmutableNode> parents,
                                        ImmutableNode root)
        Updates the mapping from nodes to their parents for the passed in hierarchy of nodes. This method traverses all children and grand-children of the passed in root node. For each node in the subtree the parent relation is added to the map.
        Parameters:
        parents - the map with parent nodes
        root - the root node of the current tree
      • valuesNotEmpty

        private static boolean valuesNotEmpty​(java.lang.Iterable<?> values)
        Checks whether the specified collection with values is not empty.
        Parameters:
        values - the collection with node values
        Returns:
        true if values are provided, false otherwise
      • addNodes

        public void addNodes​(java.lang.String key,
                             java.util.Collection<? extends ImmutableNode> nodes,
                             NodeKeyResolver<ImmutableNode> resolver)
        Description copied from interface: NodeModel
        Adds a collection of new nodes to this model. This operation corresponds to the addNodes() method of the HierarchicalConfiguration interface. The new nodes are either added to an existing node (if the passed in key selects exactly one node) or to a newly created node. The passed in NodeKeyResolver is used to interpret the given key.
        Specified by:
        addNodes in interface NodeModel<ImmutableNode>
        Parameters:
        key - the key
        nodes - the collection of nodes to be added (may be null)
        resolver - the NodeKeyResolver
      • addNodes

        public void addNodes​(java.lang.String key,
                             NodeSelector selector,
                             java.util.Collection<? extends ImmutableNode> nodes,
                             NodeKeyResolver<ImmutableNode> resolver)
        Adds new nodes using a tracked node as root node. This method works like the normal addNodes() method, but the origin of the operation (also for the interpretation of the passed in key) is a tracked node identified by the passed in NodeSelector. The selector can be null, then the root node is assumed.
        Parameters:
        key - the key
        selector - the NodeSelector defining the root node (or null)
        nodes - the collection of new nodes to be added
        resolver - the NodeKeyResolver
        Throws:
        ConfigurationRuntimeException - if the selector cannot be resolved
      • addProperty

        public void addProperty​(java.lang.String key,
                                java.lang.Iterable<?> values,
                                NodeKeyResolver<ImmutableNode> resolver)
        Description copied from interface: NodeModel
        Adds a new property to this node model consisting of an arbitrary number of values. The key for the add operation is provided. For each value a new node has to be added. The passed in resolver is queried for a NodeAddData object defining the add operation to be performed.
        Specified by:
        addProperty in interface NodeModel<ImmutableNode>
        Parameters:
        key - the key
        values - the values to be added at the position defined by the key
        resolver - the NodeKeyResolver
      • addProperty

        public void addProperty​(java.lang.String key,
                                NodeSelector selector,
                                java.lang.Iterable<?> values,
                                NodeKeyResolver<ImmutableNode> resolver)
        Adds new property values using a tracked node as root node. This method works like the normal addProperty() method, but the origin of the operation (also for the interpretation of the passed in key) is a tracked node identified by the passed in NodeSelector. The selector can be null, then the root node is assumed.
        Parameters:
        key - the key
        selector - the NodeSelector defining the root node (or null)
        values - the values to be added
        resolver - the NodeKeyResolver
        Throws:
        ConfigurationRuntimeException - if the selector cannot be resolved
      • clear

        public void clear​(NodeKeyResolver<ImmutableNode> resolver)
        Removes all data from this model. A new empty root node is created with the same name as the current root node. Implementation note: Because this is a hard reset the usual dance for dealing with concurrent updates is not required here.
        Specified by:
        clear in interface NodeModel<ImmutableNode>
        Parameters:
        resolver - the NodeKeyResolver
      • clearProperty

        public void clearProperty​(java.lang.String key,
                                  NodeKeyResolver<ImmutableNode> resolver)
        Clears the value of a property. This method is similar to NodeModel.clearTree(String, NodeKeyResolver): However, the nodes referenced by the passed in key are not removed completely, but only their value is set to null. If this operation leaves an affected node in an undefined state, it is removed from the model.
        Specified by:
        clearProperty in interface NodeModel<ImmutableNode>
        Parameters:
        key - the key selecting the properties to be cleared
        resolver - the NodeKeyResolver
      • clearProperty

        public void clearProperty​(java.lang.String key,
                                  NodeSelector selector,
                                  NodeKeyResolver<ImmutableNode> resolver)
        Clears a property using a tracked node as root node. This method works like the normal clearProperty() method, but the origin of the operation (also for the interpretation of the passed in key) is a tracked node identified by the passed in NodeSelector. The selector can be null, then the root node is assumed.
        Parameters:
        key - the key
        selector - the NodeSelector defining the root node (or null)
        resolver - the NodeKeyResolver
        Throws:
        ConfigurationRuntimeException - if the selector cannot be resolved
      • clearTree

        public java.util.List<QueryResult<ImmutableNode>> clearTree​(java.lang.String key,
                                                                    NodeKeyResolver<ImmutableNode> resolver)
        Removes the sub trees defined by the given key from this model. All nodes selected by this key are retrieved from the specified NodeKeyResolver and removed from the model. This implementation checks whether nodes become undefined after subtrees have been removed. If this is the case, such nodes are removed, too. Return value is a collection with QueryResult objects for the elements to be removed from the model.
        Specified by:
        clearTree in interface NodeModel<ImmutableNode>
        Parameters:
        key - the key selecting the properties to be removed
        resolver - the NodeKeyResolver
        Returns:
        an object with information about the data removed
      • clearTree

        public java.util.List<QueryResult<ImmutableNode>> clearTree​(java.lang.String key,
                                                                    NodeSelector selector,
                                                                    NodeKeyResolver<ImmutableNode> resolver)
        Clears a whole sub tree using a tracked node as root node. This method works like the normal clearTree() method, but the origin of the operation (also for the interpretation of the passed in key) is a tracked node identified by the passed in NodeSelector. The selector can be null, then the root node is assumed.
        Parameters:
        key - the key
        selector - the NodeSelector defining the root node (or null)
        resolver - the NodeKeyResolver
        Returns:
        a list with the results to be removed
        Throws:
        ConfigurationRuntimeException - if the selector cannot be resolved
      • createParentMapping

        private java.util.Map<ImmutableNode,​ImmutableNode> createParentMapping​(ImmutableNode root)
        Creates the mapping to parent nodes for the nodes structured represented by the passed in root node. Each node is assigned its parent node. Here an iterative algorithm is used rather than a recursive one to avoid stack overflow for huge structures.
        Parameters:
        root - the root node of the structure
        Returns:
        the parent node mapping
      • createTreeData

        private TreeData createTreeData​(ImmutableNode root,
                                        TreeData current)
        Creates a TreeData object for the specified root node.
        Parameters:
        root - the root node of the current tree
        current - the current TreeData object (may be null)
        Returns:
        the TreeData describing the current tree
      • createTreeDataForRootAndTracker

        private TreeData createTreeDataForRootAndTracker​(ImmutableNode root,
                                                         NodeTracker newTracker)
        Creates a TreeData object for the specified root node and NodeTracker. Other parameters are set to default values.
        Parameters:
        root - the new root node for this model
        newTracker - the new NodeTracker
        Returns:
        the new TreeData object
      • executeTransactionOnCurrentStructure

        private boolean executeTransactionOnCurrentStructure​(InMemoryNodeModel.TransactionInitializer txInit,
                                                             NodeSelector selector,
                                                             TreeData currentData,
                                                             NodeKeyResolver<ImmutableNode> resolver)
        Executes a transaction on the current data of this model. This method is called if an operation is to be executed on the model's root node or a tracked node which is not yet detached.
        Parameters:
        txInit - the TransactionInitializer
        selector - an optional NodeSelector defining the target node
        currentData - the current data of the model
        resolver - the NodeKeyResolver
        Returns:
        a flag whether the operation has been completed successfully
      • executeTransactionOnDetachedTrackedNode

        private boolean executeTransactionOnDetachedTrackedNode​(InMemoryNodeModel.TransactionInitializer txInit,
                                                                NodeSelector selector,
                                                                TreeData currentData,
                                                                NodeKeyResolver<ImmutableNode> resolver)
        Tries to execute a transaction on the model of a detached tracked node. This method checks whether the target node of the transaction is a tracked node and if this node is already detached. If this is the case, the update operation is independent on this model and has to be executed on the specific model for the detached node.
        Parameters:
        txInit - the TransactionInitializer
        selector - an optional NodeSelector defining the target node
        currentData - the current data of the model
        resolver - the NodeKeyResolver @return a flag whether the transaction could be executed
        Throws:
        ConfigurationRuntimeException - if the selector cannot be resolved
      • getInMemoryRepresentation

        public ImmutableNode getInMemoryRepresentation()
        Gets a representation of the data stored in this model in form of a nodes hierarchy of ImmutableNode objects. A concrete model implementation can use an arbitrary means to store its data. When a model's data is to be used together with other functionality of the Configuration library (e.g. when combining multiple configuration sources) it has to be transformed into a common format. This is done by this method. ImmutableNode is a generic representation of a hierarchical structure. Thus, it should be possible to generate a corresponding structure from arbitrary model data. This implementation simply returns the current root node of this model.
        Specified by:
        getInMemoryRepresentation in interface NodeModel<ImmutableNode>
        Returns:
        the root node of an in-memory hierarchy representing the data stored in this model
      • getNodeHandler

        public NodeHandler<ImmutableNode> getNodeHandler()
        Gets a NodeHandler for dealing with the nodes managed by this model. InMemoryNodeModel implements the NodeHandler interface itself. So this implementation just returns the this reference.
        Specified by:
        getNodeHandler in interface NodeModel<ImmutableNode>
        Returns:
        the NodeHandler
      • getReferenceNodeHandler

        public ReferenceNodeHandler getReferenceNodeHandler()
        Gets a ReferenceNodeHandler object for this model. This extended node handler can be used to query references objects stored for this model.
        Returns:
        the ReferenceNodeHandler
      • getRootNode

        public ImmutableNode getRootNode()
        Gets the root node of this mode. Note: This method should be used with care. The model may be updated concurrently which causes the root node to be replaced. If the root node is to be processed further (e.g. by executing queries on it), the model should be asked for its NodeHandler, and the root node should be obtained from there. The connection between a node handler and its root node remain constant because an update of the model causes the whole node handler to be replaced.
        Returns:
        the current root node
      • getTrackedNode

        public ImmutableNode getTrackedNode​(NodeSelector selector)
        Gets the current ImmutableNode instance associated with the given NodeSelector. The node must be a tracked node, i.e. trackNode(NodeSelector, NodeKeyResolver) must have been called before with the given selector.
        Parameters:
        selector - the NodeSelector defining the desired node
        Returns:
        the current ImmutableNode associated with this selector
        Throws:
        ConfigurationRuntimeException - if the selector is unknown
      • getTrackedNodeHandler

        public NodeHandler<ImmutableNode> getTrackedNodeHandler​(NodeSelector selector)
        Gets a NodeHandler for a tracked node. Such a handler may be required for operations on a sub tree of the model. The handler to be returned depends on the current state of the tracked node. If it is still active, a handler is used which shares some data (especially the parent mapping) with this model. Detached track nodes in contrast have their own separate model; in this case a handler associated with this model is returned.
        Parameters:
        selector - the NodeSelector defining the tracked node
        Returns:
        a NodeHandler for this tracked node
        Throws:
        ConfigurationRuntimeException - if the selector is unknown
      • getTreeData

        TreeData getTreeData()
        Gets the current TreeData object. This object contains all information about the current node structure.
        Returns:
        the current TreeData object
      • initializeAddTransaction

        private void initializeAddTransaction​(ModelTransaction tx,
                                              java.lang.String key,
                                              java.lang.Iterable<?> values,
                                              NodeKeyResolver<ImmutableNode> resolver)
        Initializes a transaction for an add operation.
        Parameters:
        tx - the transaction to be initialized
        key - the key
        values - the collection with node values
        resolver - the NodeKeyResolver
      • isTrackedNodeDetached

        public boolean isTrackedNodeDetached​(NodeSelector selector)
        Returns a flag whether the specified tracked node is detached. As long as the NodeSelector associated with that node returns a single instance, the tracked node is said to be life. If now an update of the model happens which invalidates the selector (maybe the target node was removed), the tracked node becomes detached. It is still possible to query the node; here the latest valid instance is returned. But further changes on the node model are no longer tracked for this node. So even if there are further changes which would make the NodeSelector valid again, the tracked node stays in detached state.
        Parameters:
        selector - the NodeSelector defining the desired node
        Returns:
        a flag whether this tracked node is in detached state
        Throws:
        ConfigurationRuntimeException - if the selector is unknown
      • mergeRoot

        public void mergeRoot​(ImmutableNode node,
                              java.lang.String rootName,
                              java.util.Map<ImmutableNode,​?> references,
                              java.lang.Object rootRef,
                              NodeKeyResolver<ImmutableNode> resolver)
        Merges the root node of this model with the specified node. This method is typically caused by configuration implementations when a configuration source is loaded, and its data has to be added to the model. It is possible to define the new name of the root node and to pass in a map with reference objects.
        Parameters:
        node - the node to be merged with the root node
        rootName - the new name of the root node; can be null, then the name of the root node is not changed unless it is null
        references - an optional map with reference objects
        rootRef - an optional reference object for the new root node
        resolver - the NodeKeyResolver
      • replaceActiveTrackedNode

        private boolean replaceActiveTrackedNode​(TreeData currentData,
                                                 NodeSelector selector,
                                                 ImmutableNode newNode)
        Replaces an active tracked node. The node then becomes detached.
        Parameters:
        currentData - the current data of the model
        selector - the NodeSelector defining the tracked node
        newNode - the node replacing the tracked node
        Returns:
        a flag whether the operation was successful
      • replaceDetachedTrackedNode

        private boolean replaceDetachedTrackedNode​(TreeData currentData,
                                                   NodeSelector selector,
                                                   ImmutableNode newNode)
        Replaces a tracked node if it is already detached.
        Parameters:
        currentData - the current data of the model
        selector - the NodeSelector defining the tracked node
        newNode - the node replacing the tracked node
        Returns:
        a flag whether the operation was successful
      • replaceRoot

        public void replaceRoot​(ImmutableNode newRoot,
                                NodeKeyResolver<ImmutableNode> resolver)
        Replaces the root node of this model. This method is similar to setRootNode(ImmutableNode); however, tracked nodes will not get lost. The model applies the selectors of all tracked nodes on the new nodes hierarchy, so that corresponding nodes are selected (this may cause nodes to become detached if a select operation fails). This operation is useful if the new nodes hierarchy to be set is known to be similar to the old one. Note that reference objects are lost; there is no way to automatically match nodes between the old and the new nodes hierarchy.
        Parameters:
        newRoot - the new root node to be set (must not be null)
        resolver - the NodeKeyResolver
        Throws:
        java.lang.IllegalArgumentException - if the new root node is null
      • replaceTrackedNode

        public void replaceTrackedNode​(NodeSelector selector,
                                       ImmutableNode newNode)
        Replaces a tracked node by another node. If the tracked node is not yet detached, it becomes now detached. The passed in node (which must not be null) becomes the new root node of an independent model for this tracked node. Further updates of this model do not affect the tracked node's model and vice versa.
        Parameters:
        selector - the NodeSelector defining the tracked node
        newNode - the node replacing the tracked node (must not be null)
        Throws:
        ConfigurationRuntimeException - if the selector cannot be resolved
        java.lang.IllegalArgumentException - if the replacement node is null
      • selectAndTrackNodes

        public java.util.Collection<NodeSelector> selectAndTrackNodes​(java.lang.String key,
                                                                      NodeKeyResolver<ImmutableNode> resolver)
        Allows tracking all nodes selected by a key. This method evaluates the specified key on the current nodes structure. For all selected nodes corresponding NodeSelector objects are created, and they are tracked. The returned collection of NodeSelector objects can be used for interacting with the selected nodes.
        Parameters:
        key - the key for selecting the nodes to track
        resolver - the NodeKeyResolver
        Returns:
        a collection with the NodeSelector objects for the new tracked nodes
      • setProperty

        public void setProperty​(java.lang.String key,
                                NodeSelector selector,
                                java.lang.Object value,
                                NodeKeyResolver<ImmutableNode> resolver)
        Sets the value of a property using a tracked node as root node. This method works like the normal setProperty() method, but the origin of the operation (also for the interpretation of the passed in key) is a tracked node identified by the passed in NodeSelector. The selector can be null, then the root node is assumed.
        Parameters:
        key - the key
        selector - the NodeSelector defining the root node (or null)
        value - the new value for this property
        resolver - the NodeKeyResolver
        Throws:
        ConfigurationRuntimeException - if the selector cannot be resolved
      • setProperty

        public void setProperty​(java.lang.String key,
                                java.lang.Object value,
                                NodeKeyResolver<ImmutableNode> resolver)
        Description copied from interface: NodeModel
        Changes the value of a property. This is a more complex operation as it might involve adding, updating, or deleting nodes and attributes from the model. The object representing the new value is passed to the NodeKeyResolver which will produce a corresponding NodeUpdateData object. Based on the content of this object, update operations are performed.
        Specified by:
        setProperty in interface NodeModel<ImmutableNode>
        Parameters:
        key - the key
        value - the new value for this property (to be evaluated by the NodeKeyResolver)
        resolver - the NodeKeyResolver
      • setRootNode

        public void setRootNode​(ImmutableNode newRoot)
        Sets a new root node for this model. The whole structure is replaced by the new node and its children. All tracked nodes and reference objects managed by this model are cleared.Care has to be taken when this method is used and the model is accessed by multiple threads. It is not deterministic which concurrent operations see the old root and which see the new root node.
        Specified by:
        setRootNode in interface NodeModel<ImmutableNode>
        Parameters:
        newRoot - the new root node to be set (can be null, then an empty root node is set)
      • trackChildNodes

        public java.util.Collection<NodeSelector> trackChildNodes​(java.lang.String key,
                                                                  NodeKeyResolver<ImmutableNode> resolver)
        Tracks all nodes which are children of the node selected by the passed in key. If the key selects exactly one node, for all children of this node NodeSelector objects are created, and they become tracked nodes. The returned collection of NodeSelector objects can be used for interacting with the selected nodes.
        Parameters:
        key - the key for selecting the parent node whose children are to be tracked
        resolver - the NodeKeyResolver
        Returns:
        a collection with the NodeSelector objects for the new tracked nodes
      • trackChildNodeWithCreation

        public NodeSelector trackChildNodeWithCreation​(java.lang.String key,
                                                       java.lang.String childName,
                                                       NodeKeyResolver<ImmutableNode> resolver)
        Tracks a node which is a child of another node selected by the passed in key. If the selected node has a child node with this name, it is tracked and its selector is returned. Otherwise, a new child node with this name is created first.
        Parameters:
        key - the key for selecting the parent node
        childName - the name of the child node
        resolver - the NodeKeyResolver
        Returns:
        the NodeSelector for the tracked child node
        Throws:
        ConfigurationRuntimeException - if the passed in key does not select a single node
      • trackNode

        public void trackNode​(NodeSelector selector,
                              NodeKeyResolver<ImmutableNode> resolver)
        Adds a node to be tracked. After this method has been called with a specific NodeSelector, the node associated with this key can be always obtained using getTrackedNode(NodeSelector) with the same selector. This is useful because during updates of a model parts of the structure are replaced. Therefore, it is not a good idea to simply hold a reference to a node; this might become outdated soon. Rather, the node should be tracked. This mechanism ensures that always the correct node reference can be obtained.
        Parameters:
        selector - the NodeSelector defining the desired node
        resolver - the NodeKeyResolver
        Throws:
        ConfigurationRuntimeException - if the selector does not select a single node
      • untrackNode

        public void untrackNode​(NodeSelector selector)
        Removes a tracked node. This method is the opposite of trackNode(). It has to be called if there is no longer the need to track a specific node. Note that for each call of trackNode() there has to be a corresponding untrackNode() call. This ensures that multiple observers can track the same node.
        Parameters:
        selector - the NodeSelector defining the desired node
        Throws:
        ConfigurationRuntimeException - if the specified node is not tracked
      • updateModel

        private void updateModel​(InMemoryNodeModel.TransactionInitializer txInit,
                                 NodeSelector selector,
                                 NodeKeyResolver<ImmutableNode> resolver)
        Performs a non-blocking, thread-safe update of this model based on a transaction initialized by the passed in initializer. This method uses the atomic reference for the model's current data to ensure that an update was successful even if the model is concurrently accessed.
        Parameters:
        txInit - the TransactionInitializer
        selector - an optional NodeSelector defining the target node of the transaction
        resolver - the NodeKeyResolver