/*
* Artificial Intelligence for Humans
* Volume 2: Nature Inspired Algorithms
* Java Version
* http://www.aifh.org
* http://www.jeffheaton.com
*
* Code repository:
* https://github.com/jeffheaton/aifh
*
* Copyright 2014 by Jeff Heaton
*
* Licensed 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.
*
* For more information on Heaton Research copyrights, licenses
* and trademarks visit:
* http://www.heatonresearch.com/copyright
*/
package com.heatonresearch.aifh.general.collections;
import com.heatonresearch.aifh.randomize.GenerateRandom;
import com.heatonresearch.aifh.randomize.RandomChoice;
import java.io.Serializable;
import java.util.ArrayList;
import java.util.List;
/**
* This class is used to choose between several objects with a specified probability.
*
* @param <T> The type of object to choose from.
*/
public class ChooseObject<T> implements Serializable {
/**
* The objects that we are choosing from.
*/
private final List<ObjectHolder<T>> list = new ArrayList<ObjectHolder<T>>();
/**
* The random choose.
*/
private RandomChoice chooser;
/**
* Finalize the structure and set the probabilities.
*/
public void finalizeStructure() {
double[] d = new double[size()];
for (int i = 0; i < size(); i++) {
d[i] = list.get(i).getProbability();
}
this.chooser = new RandomChoice(d);
}
/**
* Add an object.
*
* @param probability The probability to choose this object.
* @param opp The object to add.
*/
public void add(double probability, T opp) {
list.add(new ObjectHolder<T>(opp, probability));
}
/**
* @return The number of objects added.
*/
public int size() {
return list.size();
}
/**
* Choose a random object.
*
* @param theGenerator Random number generator.
* @return The random choice.
*/
public T pick(GenerateRandom theGenerator) {
int index = this.chooser.generate(theGenerator);
return this.list.get(index).getObj();
}
/**
* @return The object to choose from.
*/
public List<ObjectHolder<T>> getList() {
return this.list;
}
/**
* CLear all objects from the collection.
*/
public void clear() {
this.list.clear();
}
/**
* @return The first object in the list.
*/
public T pickFirst() {
return this.list.get(0).getObj();
}
}