UA-.NETStandard/Libraries/Opc.Ua.Server/Fluent/INodeBuilder.cs

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namespace Opc.Ua.Server.Fluent
{
    /// <summary>
    /// Per-node fluent surface returned by
    /// <see cref="INodeManagerBuilder.Node(string)"/>. All <c>On*</c>
    /// methods return the same builder so calls can be chained.
    /// </summary>
    /// <remarks>
    /// <para>
    /// Variable-only callbacks (e.g. <c>OnRead</c>) and method-only
    /// callbacks (e.g. <c>OnCall</c>) throw
    /// <see cref="ServiceResultException"/> with
    /// <see cref="StatusCodes.BadInvalidArgument"/> when invoked on a node
    /// of an incompatible class. Use <see cref="As{TState}"/> to obtain a
    /// strongly-typed view that surfaces the right callbacks at compile
    /// time.
    /// </para>
    /// <para>
    /// All callbacks replace any previously assigned handler on the
    /// underlying <see cref="NodeState"/>; they do not add to a list.
    /// Wiring the same node twice with the same callback category is an
    /// error and throws.
    /// </para>
    /// </remarks>
    public interface INodeBuilder : INodeStateBuilder
    {
        /// <summary>
        /// The resolved <see cref="NodeState"/>. Exposed so callers can
        /// reach attributes that are not surfaced by the builder (for
        /// example, setting <c>UserAccessLevel</c> programmatically).
        /// </summary>
        new NodeState Node { get; }

        /// <summary>
        /// The owning builder. Useful when you want to terminate a chain
        /// and resolve another node without storing the parent reference.
        /// </summary>
        INodeManagerBuilder Builder { get; }

        /// <summary>
        /// Returns a strongly-typed view of the same node. Throws if the
        /// resolved node is not assignable to <typeparamref name="TState"/>.
        /// </summary>
        /// <typeparam name="TState">The expected node state type.</typeparam>
        /// <exception cref="ServiceResultException">
        /// The resolved node is not assignable to <typeparamref name="TState"/>.
        /// </exception>
        INodeBuilder<TState> As<TState>() where TState : NodeState;

        /// <summary>
        /// Wires <see cref="BaseVariableState.OnReadValue"/>.
        /// </summary>
        INodeBuilder OnRead(NodeValueEventHandler handler);

        /// <summary>
        /// Wires <see cref="BaseVariableState.OnSimpleReadValue"/>.
        /// </summary>
        INodeBuilder OnRead(NodeValueSimpleEventHandler handler);

        /// <summary>
        /// Wires <see cref="BaseVariableState.OnWriteValue"/>.
        /// </summary>
        INodeBuilder OnWrite(NodeValueEventHandler handler);

        /// <summary>
        /// Wires <see cref="BaseVariableState.OnSimpleWriteValue"/>.
        /// </summary>
        INodeBuilder OnWrite(NodeValueSimpleEventHandler handler);

        /// <summary>
        /// Wires <see cref="BaseVariableState.OnReadValueAsync"/>. Use this
        /// overload when the read source performs I/O — the handler runs
        /// without holding <c>lock(this)</c>, so the call can <c>await</c>
        /// freely.
        /// </summary>
        INodeBuilder OnRead(NodeValueEventHandlerAsync handler);

        /// <summary>
        /// Wires <see cref="BaseVariableState.OnSimpleReadValueAsync"/>.
        /// The framework still applies index-range / data-encoding /
        /// copy-policy post-processing to the returned value.
        /// </summary>
        INodeBuilder OnRead(NodeValueSimpleEventHandlerAsync handler);

        /// <summary>
        /// Wires <see cref="BaseVariableState.OnWriteValueAsync"/>.
        /// </summary>
        INodeBuilder OnWrite(NodeValueWriteEventHandlerAsync handler);

        /// <summary>
        /// Wires <see cref="BaseVariableState.OnSimpleWriteValueAsync"/>.
        /// </summary>
        INodeBuilder OnWrite(NodeValueSimpleWriteEventHandlerAsync handler);

        /// <summary>
        /// Wires <see cref="MethodState.OnCallMethod2"/>.
        /// </summary>
        INodeBuilder OnCall(GenericMethodCalledEventHandler2 handler);

        /// <summary>
        /// Wires <see cref="MethodState.OnCallMethod2Async"/>.
        /// </summary>
        INodeBuilder OnCall(GenericMethodCalledEventHandler2Async handler);

        /// <summary>
        /// Invoked exactly once after the node has been added to the
        /// address space and all sibling builder wiring has been applied.
        /// </summary>
        INodeBuilder OnNodeAdded(NodeLifecycleHandler handler);

        /// <summary>
        /// Invoked when the node manager removes the node from the address
        /// space (including manager dispose).
        /// </summary>
        INodeBuilder OnNodeRemoved(NodeLifecycleHandler handler);

        /// <summary>
        /// Routes <c>CustomNodeManager2.HistoryRead</c> requests targeting
        /// the resolved node to <paramref name="handler"/>.
        /// </summary>
        INodeBuilder OnHistoryRead(HistoryReadHandler handler);

        /// <summary>
        /// Routes <c>CustomNodeManager2.HistoryUpdate</c> requests targeting
        /// the resolved node to <paramref name="handler"/>.
        /// </summary>
        INodeBuilder OnHistoryUpdate(HistoryUpdateHandler handler);

        /// <summary>
        /// Routes <c>CustomNodeManager2.ConditionRefresh</c> invocations
        /// whose monitored item targets the resolved node to
        /// <paramref name="handler"/>.
        /// </summary>
        INodeBuilder OnConditionRefresh(ConditionRefreshHandler handler);

        /// <summary>
        /// Invoked once a monitored item has been successfully created for
        /// the resolved source node. Useful for attaching push-style
        /// sampling sources.
        /// </summary>
        INodeBuilder OnMonitoredItemCreated(MonitoredItemCreatedHandler handler);

        /// <summary>
        /// Wires the resolved node's <see cref="NodeState.OnReportEvent"/>
        /// hook to forward events to <paramref name="handler"/>.
        /// </summary>
        INodeBuilder OnEvent(EventNotificationHandler handler);

        /// <summary>
        /// Opts the resolved node into (or out of) dynamic scaling of event
        /// consumer tasks. When enabled, the <see cref="MonitoredNode2"/>
        /// for this node scales consumer tasks with the number of event
        /// monitored items, improving throughput under high event loads.
        /// The Server node (<see cref="ObjectIds.Server"/>) is always
        /// auto-opted-in regardless of this call.
        /// </summary>
        /// <param name="enable">
        /// <c>true</c> to opt in (default); <c>false</c> to opt out.
        /// </param>
        INodeBuilder AllowMultipleEventConsumers(bool enable = true);

        /// <summary>
        /// Resolves a child of the current node by browse name. Used by
        /// source-generated typed traversal wrappers to walk one segment
        /// at a time without re-resolving from the root.
        /// </summary>
        /// <param name="browseName">Browse name of the immediate child.</param>
        /// <exception cref="ServiceResultException">
        /// Thrown when the child cannot be found.
        /// </exception>
        new INodeBuilder Child(QualifiedName browseName);

        /// <summary>
        /// Strongly-typed sibling of <see cref="Child(QualifiedName)"/>.
        /// </summary>
        /// <typeparam name="TState">
        /// CLR <see cref="NodeState"/> type the resolved child must be
        /// assignable to.
        /// </typeparam>
        new INodeBuilder<TState> Child<TState>(QualifiedName browseName)
            where TState : NodeState;

        /// <summary>
        /// Resolves a variable child of the current node and returns a
        /// typed <see cref="IVariableBuilder{TValue}"/> view.
        /// </summary>
        /// <typeparam name="TValue">
        /// CLR type carried by the child variable's <c>Value</c> attribute.
        /// </typeparam>
        /// <param name="browseName">Browse name of the immediate child.</param>
        /// <exception cref="ServiceResultException">
        /// Thrown when the child cannot be found, or when it is not a
        /// <see cref="BaseVariableState"/>.
        /// </exception>
        IVariableBuilder<TValue> Variable<TValue>(QualifiedName browseName);
    }

    /// <summary>
    /// Strongly-typed view of <see cref="INodeBuilder"/> that narrows the
    /// <see cref="Node"/> property to <typeparamref name="TState"/>. All
    /// inherited <c>On*</c> methods continue to return the non-generic
    /// builder; use <see cref="INodeBuilder.As{TState}"/> chaining when
    /// you need to restore the typed view.
    /// </summary>
    /// <typeparam name="TState">
    /// The concrete <see cref="NodeState"/> derivative the resolved node
    /// is narrowed to.
    /// </typeparam>
    public interface INodeBuilder<out TState> : INodeBuilder, INodeStateBuilder<TState>
        where TState : NodeState
    {
        /// <summary>
        /// The resolved node, narrowed to <typeparamref name="TState"/>.
        /// </summary>
        new TState Node { get; }
    }
}