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   *  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
   *
   *    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
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  package org.apache.cayenne.datafactory;
  
  import java.util.Random;
  
  /**
   * @since 4.0
   */
  public abstract class DictionaryValueProvider<T> implements ValueProvider<T> {
  
      private Random random = ValueProvider.RANDOM;
  
      public DictionaryValueProvider(Random random) {
          this.random = random;
      }
  
      /**
       * Returns a random item from an array of items
       *
       * @return Item from the array
       */
      public T randomValue() {
          return randomValue(100, null);
      }
  
      /**
       * Returns a random item from an array of items or null depending on the
       * probability parameter. The probability determines the chance (in %) of
       * returning an item from the array versus null.
       *
       * @param probability
       *            chance (in %, 100 being guaranteed) of returning an item from
       *            the array
       * @return Item from the array or the default value
       */
      public T randomValue(int probability) {
          return randomValue(probability, null);
      }
  
      /**
       * Returns a random item from an array of items or the defaultItem depending
       * on the probability parameter. The probability determines the chance (in
       * %) of returning an item from the array versus the default value.
       *
       * @param probability
       *            chance (in %, 100 being guaranteed) of returning an item from
       *            the array
       * @param defaultItem
       *            value to return if the probability test fails
       * @return Item from the array or the default value
       */
      public T randomValue(int probability, T defaultItem) {
          if (values() == null) {
              throw new IllegalArgumentException("Item array cannot be null");
          }
          if (values().length == 0) {
              throw new IllegalArgumentException("Item array cannot be empty");
          }
          return chance(probability) ? values()[random.nextInt(values().length)] : defaultItem;
      }
  
      /**
       * Gives you a true/false based on a probability with a random number
       * generator. Can be used to optionally add elements.
       *
       * <pre>
       * if (DataFactory.chance(70)) {
       * 	// 70% chance of this code being executed
       * }
       * </pre>
       *
       * @param chance
       *            % chance of returning true
       * @return
       */
      public boolean chance(int chance) {
          return random.nextInt(100) < chance;
      }
  
      @Override
      public void setRandom(Random random) {
          this.random = random;
      }
  
      protected abstract T[] values();
  
  }
  