package org.wamblee.system;

public class DefaultRequiredInterfaceDescriptor extends DefaultProvidedInterfaceDescriptor
		implements RequiredInterfaceDescriptor {

	public DefaultRequiredInterfaceDescriptor(String aName, Class aInterface) {
		super(aName, aInterface);
	}

	public DefaultRequiredInterfaceDescriptor(String aName, Class[] aInterfaces) {
		super(aName, aInterfaces);
	}

	@Override
	public boolean implementedBy(ProvidedInterfaceDescriptor aDescriptor) {
		Class[] provided = aDescriptor.getInterfaceTypes();
		for (Class required : getInterfaceTypes()) {
			if ( !serviceProvided(required, provided)) { 
				return false; 
			}
		}
		// all required interfaces are provided.
		return true; 
	}
	
	/**
	 * Check if the required interface is implemented by one of the provided interfaces. 
	 * @param aRequired required interface
	 * @param aProvided Provided interfaces.
	 * @return
	 */
	private boolean serviceProvided(Class aRequired, Class[] aProvided) { 
		for (Class provided: aProvided) {
			try {
				provided.asSubclass(aRequired);
				return true; 
			} catch (ClassCastException e) {
				// No match, try the next one.
			}
		}
		return false; 
	}

}