DependencyGraph.java

/**
 *
 * Copyright (c) 2006-2017, Speedment, Inc. All Rights Reserved.
 *
 * 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 com.speedment.common.injector.dependency;

import com.speedment.common.injector.exception.CyclicReferenceException;
import java.util.stream.Stream;

/**
 * Represents the graph of dependencies in the injector.
 * 
 * @author  Emil Forslund
 * @since   1.2.0
 */
public interface DependencyGraph {
    
    /**
     * Returns the {@link DependencyNode} representing the specified type in the 
     * graph. This method might throw a {@link CyclicReferenceException} if the
     * class is in a cyclic dependency chain.
     * <p>
     * If the specified class does not exist in the graph, an 
     * {@code IllegalArgumentException} is thrown.
     * 
     * @param clazz  the class to look for in the graph
     * @return       the node found
     * 
     * @throws CyclicReferenceException  if the class is in a cyclic dependency
     * @throws IllegalArgumentException  the specified class is not in graph
     */
    DependencyNode get(Class<?> clazz) 
    throws CyclicReferenceException, IllegalArgumentException;
    
    /**
     * Returns the {@link DependencyNode} representing the specified type in the 
     * graph if one exists, else creates it and returns it.
     * 
     * @param clazz  the class to look for in the graph
     * @return       the node found or created
     */
    DependencyNode getOrCreate(Class<?> clazz);
    
    /**
     * Inject all dependency injected fields in the graph, throwing an 
     * {@link CyclicReferenceException} if any cyclic references was detected.
     * 
     * @return  a reference to this graph
     * 
     * @throws CyclicReferenceException  if cyclic reference was detected
     */
    DependencyGraph inject() throws CyclicReferenceException;
    
    /**
     * Streams over all the nodes in the graph.
     * 
     * @return  stream of nodes
     */
    Stream<DependencyNode> nodes();
    
}