org.apache.james.protocols.api.handler.AbstractProtocolHandlerChain Maven / Gradle / Ivy

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package org.apache.james.protocols.api.handler;

import java.util.LinkedList;
import java.util.List;
import java.util.stream.Collectors;


/**
 * Abstract base class for {@link ProtocolHandlerChain} implementations
 * 
 *
 */
public abstract class AbstractProtocolHandlerChain implements ProtocolHandlerChain {

    /**
     * Return an immutable List of all Handlers
     * 
     * @return handlerList
     */
    protected abstract List getHandlers();

    @Override
    @SuppressWarnings("unchecked")
    public  LinkedList getHandlers(Class type) {
        List handlers = getHandlers();
        return handlers.stream()
            .filter(type::isInstance)
            .map(handler -> (T) handler)
            .collect(Collectors.toCollection(LinkedList::new));
    }
    
    /**
     * ExtensibleHandler wiring. This should get called after the class was constructed
     * and every stuff was set
     */
    public void wireExtensibleHandlers() throws WiringException {
        List handlers = getHandlers();
        for (ProtocolHandler handler : handlers) {
            if (handler instanceof ExtensibleHandler) {
                final ExtensibleHandler extensibleHandler = (ExtensibleHandler) handler;
                final List> markerInterfaces = extensibleHandler.getMarkerInterfaces();
                for (Class markerInterface : markerInterfaces) {
                    final List extensions = getHandlers(markerInterface);
                    extensibleHandler.wireExtensions(markerInterface, extensions);
                }
            }
        }
    }
    

    @Override
    public void destroy() {
        List handlers = getHandlers(ProtocolHandler.class);
        for (ProtocolHandler handler: handlers) {
            handler.destroy();
        }
    }
}