content: /*
   * Copyright 2024-2025 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
   *
   *      https://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.alibaba.cloud.ai.graph;
  
  import static java.lang.String.format;
  
  /**
   * Defines the interface for a sub-graph node in an agent's state graph.
   */
  public interface SubGraphNode {
  
  	String PREFIX_FORMAT = "%s-%s";
  
  	/**
  	 * node identifier
  	 * @return the unique identifier for the node.
  	 */
  	String id();
  
  	/**
  	 * Returns a subgraph of the current state graph containing all reachable states from
  	 * the current state.
  	 * @return {@code StateGraph<State>} representation of the subgraph.
  	 */
  	StateGraph subGraph();
  
  	default String formatId(String nodeId) {
  		return format(PREFIX_FORMAT, id(), nodeId);
  	}
  
  	/**
  	 * Formats the given {@code subGraphNodeId} and {@code nodeId} into a single string
  	 * using a predefined prefix.
  	 * @param subGraphNodeId The ID of the sub-graph node.
  	 * @param nodeId The ID of the node.
  	 * @return A formatted string combining the prefix with the provided IDs.
  	 */
  	static String formatId(String subGraphNodeId, String nodeId) {
  		return format(PREFIX_FORMAT, subGraphNodeId, nodeId);
  	}
  
  }
  