Class AbstractNodeLoader<I>

  • All Implemented Interfaces:
    NodeLoader<I>
    Direct Known Subclasses:
    BasicItemNodeLoader

    public abstract class AbstractNodeLoader<I>
    extends Object
    implements NodeLoader<I>
    Abstract node loader implementation that does nothing/throws an exception. It is recommended that all NodeLoader implementations extend this class (or a subclass) and only override the methods they need to support. The node loader interface may be extended in the future with new methods. Default implementations will be added to this class which ensures that subclass implementation will continue to work.
    Version:
    2.10
    Author:
    Nicklas
    Last modified
    $Date: 2015-05-12 11:27:08 +0200 (ti, 12 maj 2015) $
    • Field Detail

      • log

        private static final org.slf4j.Logger log
      • debug

        private static final boolean debug
    • Constructor Detail

      • AbstractNodeLoader

        protected AbstractNodeLoader()
    • Method Detail

      • createRootNode

        public Node createRootNode​(DbControl dc,
                                   OverviewContext context,
                                   I rootItem)
        Description copied from interface: NodeLoader
        Create a root node for the given item. A root node is a node with no parent. Typically, the direction of the created node is ChildNodeDirection.ALL so that both forward and reverse child nodes are loaded.
        Specified by:
        createRootNode in interface NodeLoader<I>
        Parameters:
        dc - The DbControl to use for database access
        context - The overview context
        rootItem - The root item
        Returns:
        A root node
        Throws:
        UnsupportedOperationException - Always
      • createForwardNode

        public Node createForwardNode​(DbControl dc,
                                      OverviewContext context,
                                      Node parentNode)
        Description copied from interface: NodeLoader
        Create a forward-loading (from parent to child) node for the given parent node. The loader should use the information on the parent node to get the correct item (of type I) and create a node for that item. If the parent can have many child nodes, the loader should first create a folder-type node and put the children inside that.

        The direction of the node(s) should usually be ChildNodeDirection.FORWARD. In case there is an error (permission denied, etc.) ChildNodeDirection.NONE should be used. If there is no child item null should be returned.

        Errors, missing items, etc. should be reported as failures to the OverviewContext.

        Specified by:
        createForwardNode in interface NodeLoader<I>
        Parameters:
        dc - The DbControl to use for database access
        context - The overview context
        parentNode - The parent node
        Returns:
        A forward-loading node (may be a folder-type node with many subnodes), or null
        Throws:
        UnsupportedOperationException - Always
      • createPropertyNode

        public Node createPropertyNode​(DbControl dc,
                                       OverviewContext context,
                                       Node parentNode)
        Description copied from interface: NodeLoader
        Create a property node for the given parent node. A property node is a node that is not on the main parent-child path. It is typically a node that can't be used a root node (for example, a protocol or software). If the parent node can have many properties of this type the loader can decide if it should first create a folder-type node and put the children inside the folder, or if all child nodes should be created directly in the parent node. In the first case, the folder node should be returned. In the latter case, null should be returned.

        The direction of the node(s) should usually be ChildNodeDirection.NONE, but it may also be ChildNodeDirection.PROPERTY in case the property has sub-properties. One example is the ProtocolLoader which loads the protocol parameters as child nodes.

        In case there is an error (permission denied, etc.) ChildNodeDirection.NONE should be used. If there is no property item null should be returned (but this may also indicate that more than one node was created).

        Errors, missing items, etc. should be reported as failures to the OverviewContext.

        Specified by:
        createPropertyNode in interface NodeLoader<I>
        Parameters:
        dc - The DbControl to use for database access
        context - The overview context
        parentNode - The parent node
        Returns:
        A node (may be a folder-type node with many subnodes), or null
        Throws:
        UnsupportedOperationException - Always
      • createReverseNode

        public Node createReverseNode​(DbControl dc,
                                      OverviewContext context,
                                      Node childNode)
        Description copied from interface: NodeLoader
        Create a reverse-loading (from child to parent) node for the given child node. The loader should use the information on the child node to get the correct item (of type I) and create a node for that item. If the child can have many parent nodes, the loader should first create a folder-type node and put the parents inside that.

        The direction of the node(s) should usually be ChildNodeDirection.REVERSE. In case there is an error (permission denied, etc.) ChildNodeDirection.NONE should be used. If there is no parent item null should be returned.

        Errors, missing items, etc. should be reported as failures to the OverviewContext.

        Specified by:
        createReverseNode in interface NodeLoader<I>
        Parameters:
        dc - The DbControl to use for database access
        context - The overview context
        childNode - The child node
        Returns:
        A reverse-loading node (may be a folder-type node with many subnodes), or null
        Throws:
        UnsupportedOperationException - Always
      • loadChildNodesOfItemNode

        protected boolean loadChildNodesOfItemNode​(DbControl dc,
                                                   OverviewContext context,
                                                   Node node)
        Loads child nodes of an item-type node.
      • loadChildNodesOfFolderNode

        protected boolean loadChildNodesOfFolderNode​(DbControl dc,
                                                     OverviewContext context,
                                                     Node node)
        Iterates the children of a folder-type node and loads the children for each one of them.