/*
 * 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.lucene.util.automaton;

import org.apache.lucene.util.Accountable;
import org.apache.lucene.util.RamUsageEstimator;

/**
 * Holds one transition from an {@link Automaton}. This is typically used temporarily when iterating
 * through transitions by invoking {@link Automaton#initTransition} and {@link
 * Automaton#getNextTransition}.
 */
public class Transition implements Accountable {

  /** static estimation of bytes used */
  public static final long BYTES_USED = RamUsageEstimator.shallowSizeOfInstance(Transition.class);

  /** Sole constructor. */
  public Transition() {}

  /** Source state. */
  public int source;

  /** Destination state. */
  public int dest;

  /** Minimum accepted label (inclusive). */
  public int min;

  /** Maximum accepted label (inclusive). */
  public int max;

  /**
   * Remembers where we are in the iteration; init to -1 to provoke exception if nextTransition is
   * called without first initTransition.
   */
  int transitionUpto = -1;

  @Override
  public String toString() {
    return source + " --> " + dest + " " + (char) min + "-" + (char) max;
  }

  @Override
  public long ramBytesUsed() {
    return BYTES_USED;
  }
}
