GDLHandler.java 文件源码

/**
 * Checks valid input and creates GDL Handler.
 *
 * @param antlrInputStream ANTLR input stream
 * @return GDL handler
 */
private GDLHandler build(ANTLRInputStream antlrInputStream) {
  if (graphLabel == null) {
    throw new IllegalArgumentException("Graph label must not be null.");
  }
  if (vertexLabel == null) {
    throw new IllegalArgumentException("Vertex label must not be null.");
  }
  if (edgeLabel == null) {
    throw new IllegalArgumentException("Edge label must not be null.");
  }
  if (errorStrategy == null) {
    throw new IllegalArgumentException("Error handler must not be null.");
  }

  GDLLexer lexer = new GDLLexer(antlrInputStream);
  GDLParser parser = new GDLParser(new CommonTokenStream(lexer));
  parser.setErrorHandler(errorStrategy);

  GDLLoader loader = new GDLLoader(graphLabel, vertexLabel, edgeLabel,
    useDefaultGraphLabel, useDefaultVertexLabel, useDefaultEdgeLabel);
  new ParseTreeWalker().walk(loader, parser.database());
  return new GDLHandler(loader);
}