/*
 * 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.IntsRef;

FiniteStringsIterator which limits the number of iterated accepted strings. If more than limit strings are accepted,
the first limit strings found are returned.
If the Automaton has cycles then this iterator may throw an 
IllegalArgumentException, but this is not guaranteed! 
Be aware that the iteration order is implementation dependent
and may change across releases.
@lucene.experimental
/**
 * {@link FiniteStringsIterator} which limits the number of iterated accepted strings.
 * If more than <code>limit</code> strings are accepted,
 * the first <code>limit</code> strings found are returned.
 *
 * <p>If the {@link Automaton} has cycles then this iterator may throw an {@code
 * IllegalArgumentException}, but this is not guaranteed!
 *
 * <p>Be aware that the iteration order is implementation dependent
 * and may change across releases.
 *
 * @lucene.experimental
 */
public class LimitedFiniteStringsIterator extends FiniteStringsIterator {
  
Maximum number of finite strings to create.
/**
   * Maximum number of finite strings to create.
   */
  private int limit = Integer.MAX_VALUE;

  
Number of generated finite strings.
/**
   * Number of generated finite strings.
   */
  private int count = 0;

  
Constructor.
Params:
a – Automaton to create finite string from.
limit – Maximum number of finite strings to create, or -1 for infinite./**
   * Constructor.
   *
   * @param a Automaton to create finite string from.
   * @param limit Maximum number of finite strings to create, or -1 for infinite.
   */
  public LimitedFiniteStringsIterator(Automaton a, int limit) {
    super(a);

    if (limit != -1 && limit <= 0) {
      throw new IllegalArgumentException("limit must be -1 (which means no limit), or > 0; got: " + limit);
    }

    this.limit = limit > 0? limit : Integer.MAX_VALUE;
  }

  @Override
  public IntsRef next() {
    if (count >= limit) {
      // Abort on limit.
      return null;
    }

    IntsRef result = super.next();
    if (result != null) {
      count++;
    }

    return result;
  }

  
Number of iterated finite strings.
/**
   * Number of iterated finite strings.
   */
  public int size() {
    return count;
  }
}