Callbacks.cs

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using System;
using System.Collections.Generic;
using VDS.RDF.Query;

namespace VDS.RDF
{
    // Callback Delegates for Async operations

    /// <summary>
    /// Callback for methods that return a <see cref="SparqlResultSet">SparqlResultSet</see> asynchronously.
    /// </summary>
    /// <param name="results">SPARQL Results.</param>
    /// <param name="state">State.</param>
    /// <remarks>
    /// In the event of an error you will be passed an instance of <see cref="AsyncError"/> which will contain the error and the original state information you passed into the method that took this callback.
    /// </remarks>
    public delegate void SparqlResultsCallback(SparqlResultSet results, object state);

    /// <summary>
    /// Callback for methods that return a <see cref="IGraph">IGraph</see> asynchronously.
    /// </summary>
    /// <param name="g">Graph.</param>
    /// <param name="state">State.</param>
    /// <remarks>
    /// In the event of an error you will be passed an instance of <see cref="AsyncError"/> which will contain the error and the original state information you passed into the method that took this callback.
    /// </remarks>
    public delegate void GraphCallback(IGraph g, object state);

    /// <summary>
    /// Callback for methods that return a <see cref="ITripleStore">ITripleStore</see> asynchronously.
    /// </summary>
    /// <param name="store">Triple Store.</param>
    /// <param name="state">State.</param>
    /// <remarks>
    /// In the event of an error you will be passed an instance of <see cref="AsyncError"/> which will contain the error and the original state information you passed into the method that took this callback.
    /// </remarks>
    public delegate void TripleStoreCallback(ITripleStore store, object state);

    /// <summary>
    /// Callbacks for methods that process the resulting triples with an RDF Handler asynchronously.
    /// </summary>
    /// <param name="handler">RDF Handler.</param>
    /// <param name="state">State.</param>
    /// <remarks>
    /// In the event of an error you will be passed an instance of <see cref="AsyncError"/> which will contain the error and the original state information you passed into the method that took this callback.
    /// </remarks>
    public delegate void RdfHandlerCallback(IRdfHandler handler, object state);

    /// <summary>
    /// Callbacks for methods that process the results with an SPARQL Results Handler asynchronously.
    /// </summary>
    /// <param name="handler">SPARQL Results Handler.</param>
    /// <param name="state">State.</param>
    /// <remarks>
    /// In the event of an error you will be passed an instance of <see cref="AsyncError"/> which will contain the error and the original state information you passed into the method that took this callback.
    /// </remarks>
    public delegate void SparqlResultsHandlerCallback(ISparqlResultsHandler handler, object state);

    /// <summary>
    /// Callbacks for methods that may process the results with either an RDF or a SPARQL Results Handler.
    /// </summary>
    /// <param name="rdfHandler">RDF Handler.</param>
    /// <param name="resultsHandler">SPARQL Results Handler.</param>
    /// <param name="state">State.</param>
    /// <remarks>
    /// In the event of an error you will be passed an instance of <see cref="AsyncError"/> which will contain the error and the original state information you passed into the method that took this callback.
    /// </remarks>
    public delegate void QueryCallback(IRdfHandler rdfHandler, ISparqlResultsHandler resultsHandler, object state);

    /// <summary>
    /// Callbacks for methods that perform SPARQL Updates.
    /// </summary>
    /// <param name="state">State.</param>
    /// <remarks>
    /// In the event of an error you will be passed an instance of <see cref="AsyncError"/> which will contain the error and the original state information you passed into the method that took this callback.
    /// </remarks>
    public delegate void UpdateCallback(object state);

    /// <summary>
    /// Callback for methods that return a Namespace Map.
    /// </summary>
    /// <param name="nsmap">Namespace Map.</param>
    /// <param name="state">State.</param>
    /// <remarks>
    /// In the event of an error you will be passed an instance of <see cref="AsyncError"/> which will contain the error and the original state information you passed into the method that took this callback.
    /// </remarks>
    public delegate void NamespaceCallback(INamespaceMapper nsmap, object state);

    /// <summary>
    /// Callbacks for methods that return a list of nodes.
    /// </summary>
    /// <param name="nodes">Node List.</param>
    /// <param name="state">State.</param>
    /// <remarks>
    /// In the event of an error you will be passed an instance of <see cref="AsyncError"/> which will contain the error and the original state information you passed into the method that took this callback.
    /// </remarks>
    public delegate void NodeListCallback(List<INode> nodes, object state);

    /// <summary>
    /// Marker that will be passed to your callback in the event that an async error occurs, provides access to the error and any state that you passed in originally.
    /// </summary>
    public class AsyncError
    {
        /// <summary>
        /// Creates new async error.
        /// </summary>
        /// <param name="ex">Exception.</param>
        /// <param name="state">State.</param>
        public AsyncError(Exception ex, object state)
        {
            Error = ex;
            State = state;
        }

        /// <summary>
        /// Gets the error that occurred.
        /// </summary>
        public Exception Error { get; private set; }

        /// <summary>
        /// Gets the original state that was passed in to the async call.
        /// </summary>
        public object State { get; private set; }
    }

}