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* 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.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();
}