public synchronized InputHandler constructInputHandler(String streamId) {
        InputHandler inputHandler = new InputHandler(streamId, inputHandlerMap.size(),
                inputEntryValve, siddhiAppContext);
        StreamJunction streamJunction = streamJunctionMap.get(streamId);
        if (streamJunction == null) {
            throw new DefinitionNotExistException("Stream with stream ID " + streamId + " has not been defined");
        }
        inputDistributor.addInputProcessor(streamJunctionMap.get(streamId).constructPublisher());
        inputHandlerMap.put(streamId, inputHandler);
        return inputHandler;
    }
Manager class to handle {@link Event} insertion to Siddhi.
modules/siddhi-core/src/main/java/io/siddhi/core/stream/input/InputManager.java