Class DataNodeTreeModel

java.lang.Object
uk.ac.starlink.datanode.tree.DataNodeTreeModel
All Implemented Interfaces:
TreeModel

public class DataNodeTreeModel extends Object implements TreeModel
A TreeModel for storing DataNodes. Each Object in the TreeModel is a DataNode. Node expansion is handled carefully: children are added one child at a time with suitable TreeModelEvents fired after each one rather than providing the whole list of children at once, since this could be a time-consuming operation and might cause the user interface to lock up for longer than was acceptable.

Associated with each DataNode in the tree is a TreeModelNode, which handles some of the structure and is in fact used internally by this tree model to store the tree structure. This can be obtained using the getModelNode(uk.ac.starlink.datanode.nodes.DataNode) method and manipulated directly for more direct control over the tree structure than is possibly by manipulating DataNodes.

Author:
Mark Taylor
  • Constructor Details

    • DataNodeTreeModel

      public DataNodeTreeModel()
      Constructs a new DataNodeTreeModel with a default root node.
    • DataNodeTreeModel

      public DataNodeTreeModel(DataNode rootDataNode)
      Constructs a new DataNodeTreeModel with a given root node.
      Parameters:
      rootDataNode - the root node
  • Method Details

    • getRoot

      public Object getRoot()
      Returns the root of the tree.
      Specified by:
      getRoot in interface TreeModel
      Returns:
      tree root DataNode
    • getChild

      public Object getChild(Object parentDataNode, int index)
      Returns a given child of a node in the tree.
      Specified by:
      getChild in interface TreeModel
      Parameters:
      parentDataNode - parent DataNode
      index - index of the child of parentDataNode required
      Returns:
      child DataNode, the index'th child of parentDataNode
    • getChildCount

      public int getChildCount(Object parentDataNode)
      Returns the number of children a node currently has.

      The first time that this method is called on a node it is used as a trigger to begin node expansion. This may be a a time-consuming business, so this method will return a number of children which can be determined without delay (this may be zero), and will initiate the process of retrieving all the other children. This is done in a separate thread, and a suitable TreeModelEvent is fired each time a child arrives. The expansion process will continue until all the children have been found. No notification is currently made when the set of children is complete.

      Subsequent calls return the number of children which are currently present, but again do not offer a guarantee that more might not be about to arrive.

      Specified by:
      getChildCount in interface TreeModel
      Parameters:
      parentDataNode - DataNode object in the tree to be queried
      Returns:
      number of children
    • getCurrentChildren

      public DataNode[] getCurrentChildren(DataNode dataNode)
      Returns an array of the children currently owned by a given node. Unlike getChildCount(java.lang.Object), this does not trigger expansion of a not-currently-expanded node, it just gives a snapshot of the current state of the model.
      Parameters:
      dataNode - the node whose children are being enquired about
      Returns:
      an array of dataNode's children
    • isLeaf

      public boolean isLeaf(Object dataNode)
      Indicates whether the node is a leaf, that is cannot have any children. Non-leaf nodes may still be childless though.
      Specified by:
      isLeaf in interface TreeModel
      Parameters:
      dataNode - DataNode node to query
      Returns:
      true iff dataNode cannot support children
    • getIndexOfChild

      public int getIndexOfChild(Object parentDataNode, Object childDataNode)
      Returns the index of a given child if it is a direct child of another.

      Note this returns -1 (without error) if childDataNode does not appear in the tree at all; this appears to be required on occasion by Sun's JTree implementation, though that's not documented in the TreeModel interface.

      Specified by:
      getIndexOfChild in interface TreeModel
      Parameters:
      parentDataNode - DataNode which is the parent object
      childDataNode - DataNode which is a child of parentDataNode
      Returns:
      the child number of childDataNode within parentDataNode or -1 if it's not a child
    • valueForPathChanged

      public void valueForPathChanged(TreePath path, Object newDataNode)
      Messaged when the user has altered the value for an item.
      Specified by:
      valueForPathChanged in interface TreeModel
      Parameters:
      path - path to the altered node (all the objects in the path must be DataNodes)
      newDataNode - the DataNode which is now found at path
    • addTreeModelListener

      public void addTreeModelListener(TreeModelListener listener)
      Specified by:
      addTreeModelListener in interface TreeModel
    • removeTreeModelListener

      public void removeTreeModelListener(TreeModelListener listener)
      Specified by:
      removeTreeModelListener in interface TreeModel
    • getNodeCount

      public int getNodeCount()
      Returns the number of nodes known in this model.
      Returns:
      node count
    • containsNode

      public boolean containsNode(DataNode node)
      Indicates whether this model contains a given data node.
      Returns:
      true iff this model contains node
    • getPathToRoot

      public DataNode[] getPathToRoot(DataNode dataNode)
      Returns an array representing the position of the given DataNode in the tree. The root is the first element in the returned array, and dataNode is the last. The length of the returned array gives the node's depth in the tree. If dataNode does not exist in this model, null is returned.
      Parameters:
      dataNode - the node to find the path of
      Returns:
      the path from the root to dataNode
    • insertNode

      public void insertNode(DataNode newChild, DataNode parent, int ipos)
      Inserts a new node into the child list of a node which exists in this tree model. The model's listeners are notified. This method may be called from any thread, not just the event dispatch thread.
      Parameters:
      newChild - the new data node to insert into parent's list of children
      parent - the parent node in whose children newChild should be inserted
      ipos - the position at which the insertion should take place
    • appendNode

      public void appendNode(DataNode newChild, DataNode parent)
      Appends a new child node to the children of a node which exists in this tree model. The model's listeners are notified. This method may be called from any thread, not just the event dispatch thread.
      Parameters:
      newChild - the new data node to add at the end of parent's list of children
      parent - the parent node to whose children newChild should be appended
    • removeNode

      public void removeNode(DataNode dataNode)
      Removes a node from the tree. The model's listeners are notified. This method may be called from any thread, not just the event dispatch thread.
      Parameters:
      dataNode - the node to remove
    • replaceNode

      public void replaceNode(DataNode oldDataNode, DataNode newDataNode)
      Replaces a given data node with a new one. This only works for non-root nodes. To replace the root node, use setRoot(uk.ac.starlink.datanode.nodes.DataNode).
      Parameters:
      oldDataNode - the node to be replaced
      newDataNode - the node to replace it with
    • setRoot

      public void setRoot(DataNode rootDataNode)
      Sets the root node of the tree.
      Parameters:
      rootDataNode - the new root node
    • refreshNode

      public void refreshNode(DataNode dataNode)
      Effectively re-initialises a node. Its children are removed from the tree, and any subsequent attempts to read the children (triggered by getChildCount) will cause them to be re-acquired from the DataNode.
      Parameters:
      dataNode - the node to refresh
    • repaintNode

      public void repaintNode(DataNode dataNode)
      Refreshes the representation of the node iteself. It is redrawn, but nothing is done about its children.
      Parameters:
      dataNode - the node to repaint
    • stopExpansion

      public void stopExpansion(DataNode dataNode)
      Stops a node from expanding. If the given node is currently undergoing expansion, calling this will stop it, leaving in place any children which have already been added to it. Processing work associated with the expansion should be stopped, though this may not happen immediately. If the given node is not undergoing expansion this method will have no effect.
      Parameters:
      dataNode - the node whose expansion is to be stopped
    • getModelNode

      public TreeModelNode getModelNode(DataNode dataNode)
      Returns the TreeModelNode which acts as the container for a given data node.
      Parameters:
      dataNode - the data node whose model node is required
      Returns:
      dataNode's container model node
    • makeModelNode

      public TreeModelNode makeModelNode(DataNode dataNode, TreeModelNode parent)
      Creates a new TreeModelNode for use in this TreeModel. Note that this method should be used rather than the TreeModelNode constructor, since this model needs to be able to keep track of the nodes that have been created.
      Parameters:
      dataNode - the DataNode managed by this TreeModelNode
      parent - the parent of this node (null for the root)