/*
 * Copyright 2008 the original author or authors.
 * 
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * 
 *      http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.wamblee.system.graph.component;

import java.util.ArrayList;
import java.util.List;

import org.wamblee.system.graph.DefaultEdge;
import org.wamblee.system.graph.Edge;
import org.wamblee.system.graph.EdgeFactory;
import org.wamblee.system.graph.Node;

/**
 * Factory that creates edges between required and provided interfaces.
 * Speciflcally it creates: 
 * <ul>
 *   <li> Edges between provided and required interfaces of a container. </li>
 *   <li> Edges between required and externally required interfaces </li>
 *   <li> Edges between externally provided and provided interfaces.  
 * </ul>
 * 
 * @author Erik Brakkee
 * 
 */
public class RequiredProvidedEdgeFactory implements EdgeFactory {

    public RequiredProvidedEdgeFactory() {
        // Empty.
    }

    @Override
    public List<Edge> create(Node aFrom, Node aTo) {
        List<Edge> result = new ArrayList<Edge>();
        if (aFrom instanceof RequiredInterfaceNode) {
            RequiredInterfaceNode required = (RequiredInterfaceNode) aFrom;
            if (aTo instanceof ProvidedInterfaceNode) {
             
                ProvidedInterfaceNode provided = (ProvidedInterfaceNode) aTo;
                if (required.getRequired()
                        .implementedBy(provided.getProvided())) {
                    result.add(new DefaultEdge(required, provided));
                }
            } else if (aTo instanceof ExternalRequiredInterfaceNode) {
                ExternalRequiredInterfaceNode external = (ExternalRequiredInterfaceNode) aTo;
                if ( external.getRequired().covers(required.getRequired())) { 
                    result.add(new DefaultEdge(required, external));
                }
            }
        } else if ( aFrom instanceof ProvidedInterfaceNode) { 
            ProvidedInterfaceNode provided = (ProvidedInterfaceNode)aFrom;
            if ( aTo instanceof ExternalProvidedInterfaceNode) { 
                ExternalProvidedInterfaceNode external = (ExternalProvidedInterfaceNode)aTo;
                if (provided.getProvided().covers(external.getProvided())) { 
                    result.add(new DefaultEdge(external, provided));
                }
            }
        }
        return result;
    }

}