Graph.java

/**
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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.apache.tajo.engine.planner.graph;

import org.apache.tajo.annotation.Nullable;

import java.util.Collection;

/**
 * This is the topmost graph interface. It only provides essential graph features.
 * @param <V> Vertex class
 * @param <E> Edge Class
 */

public interface Graph<V, E> {
  int getVertexSize();

  int getEdgeNum();

  void addEdge(V tail, V head, E edge);

  void removeEdge(V tail, V head);

  boolean hasEdge(V tail, V head);

  @Nullable E getEdge(V tail, V head);

  Collection<E> getEdgesAll();
}