/*
 * 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 org.wamblee.system.core.SystemAssemblyException;
import org.wamblee.system.graph.Edge;
import org.wamblee.system.graph.Node;
import org.wamblee.system.graph.Visitor;

/**
 * Visitor that checks externally required services: 
 * <ul>
 *   <li>
 * </ul>
 * 
 * @author Erik Brakkee
 *
 */
public class CheckExternallyRequiredVisitor implements Visitor {
    
    public CheckExternallyRequiredVisitor() { 
        // Empty.
    }

    @Override
    public void visitEdge(Edge aEdge) {
        // Empty.
    }

    @Override
    public void visitNode(Node aNode) {
        if ( aNode instanceof ExternalRequiredInterfaceNode) { 
            ExternalRequiredInterfaceNode required = (ExternalRequiredInterfaceNode) aNode; 
            if ( !required.getRequired().isOptional() && required.getRequired().getProvider() == null) { 
                throw new SystemAssemblyException(aNode + ": External required interface is not provided");
            }
        }
    }

}