1 /* 2 * Copyright (C) 2017 The Libphonenumber Authors. 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 package com.google.i18n.phonenumbers.metadata.regex; 18 19 import com.google.auto.value.AutoValue; 20 21 /** 22 * Value type for nodes in NFA graphs of phone number regular expressions. This is basically a 23 * trivial wrapper for an {@code int}, but it makes a lot of other pieces of code type safe. 24 * Outside this package, this type is mainly used for examining NFA graphs which represent a 25 * regular expression, generated via {@link RangeTreeConverter#toNfaGraph}. 26 */ 27 @AutoValue 28 public abstract class Node implements Comparable<Node> { 29 /** The unique initial node in an NFA graph with in-order zero. */ 30 public static final Node INITIAL = new AutoValue_Node(0); 31 /** The unique terminal node in an NFA graph with out-order zero. */ 32 public static final Node TERMINAL = new AutoValue_Node(1); 33 34 /** Returns a new node whose ID is one greater than this node. */ createNext()35 public Node createNext() { 36 return (id() == 0) ? TERMINAL : new AutoValue_Node(id() + 1); 37 } 38 39 /** Returns the numeric ID of this node, which must be unique within an NFA graph. */ id()40 abstract int id(); 41 42 @Override compareTo(Node o)43 public int compareTo(Node o) { 44 return Integer.compare(id(), o.id()); 45 } 46 47 @Override toString()48 public final String toString() { 49 return Integer.toString(id()); 50 } 51 } 52