INode.h

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#ifndef WIRECELL_INODE
#define WIRECELL_INODE

#include "WireCellUtil/IComponent.h"

#include <boost/any.hpp>

#include <memory>
#include <vector>

namespace WireCell {

    /** A data flow node
     */ 
    class INode : public IComponent<INode> {
    public:

        virtual ~INode();

        enum NodeCategory {
            unknown,
            sourceNode,         // one pointer output
            sinkNode,           // one pointer input
            functionNode,       // one pointer input / output
            queuedoutNode,      // one pointer input, queue of output
            joinNode,           // tuple input, pointer output
            splitNode,          // pointer input, tuple output
            faninNode,          // vector input, pointer output
            fanoutNode,         // pointer input, vector output
            multioutNode,       // pointer input multi-queue output
            hydraNode,          // multi-queue input and output
        };

        /// Return the behavior category type
        virtual NodeCategory category() = 0;

        // fixme: I can probably remove this from the API.
        /// The signature is string unique to all classes that
        /// implement a particular calling signature.  These should be
        /// defined in lower level interfaces such as a mythical
        /// IMyFooToBarConverter.
        virtual std::string signature() = 0;
        
        // Subclasses may override to provide the number of instances
        // that can run concurrently.  Default is 1.  Return 0 for
        // unlimited.  If the implementation buffers data between
        // calls to its signature it should likely return 1.
        virtual int concurrency() { return 1; }

        // Return string representations of the C++ types this node takes as input.
        // When a node is used in a DFP graph, these enumerate the input ports.
        virtual std::vector<std::string> input_types() {
            return std::vector<std::string> ();
        }
        // Return string representations of the C++ types this node produces as output.
        // When a node is used in a DFP graph, these enumerate the output ports.
        virtual std::vector<std::string>  output_types() {
            return std::vector<std::string> ();
        }

        
        /// Optional hook to be implemented in order to reset after an
        /// end of stream is encountered.  Fixme: this should be removed.
        virtual void reset() {
        }

    };
}


#endif