net.joala.data.random.AbstractRandomNumberProvider.java Source code

Introduction

Here is the source code for net.joala.data.random.AbstractRandomNumberProvider.java

Source

/*
 * Copyright 2012 CoreMedia AG
 *
 * This file is part of Joala.
 *
 * Joala is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * Joala is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with Joala.  If not, see <http://www.gnu.org/licenses/>.
 */

package net.joala.data.random;

import com.google.common.annotations.VisibleForTesting;
import com.google.common.base.MoreObjects;
import com.google.common.collect.Range;
import net.joala.data.DataProvidingException;

import javax.annotation.Nonnull;
import javax.annotation.Nullable;
import java.util.Random;

import static com.google.common.base.Preconditions.checkNotNull;
import static com.google.common.base.Preconditions.checkState;

/**
 * <p>
 * Abstract data provider for numbers. Numbers are expected to be comparable.
 * </p>
 *
 * @param <T> the number type you can retrieve from this data provider
 * @deprecated Will be removed soon.
 */
@SuppressWarnings("deprecation")
@Deprecated
public abstract class AbstractRandomNumberProvider<T extends Comparable<? extends Number>>
        extends AbstractRandomDataProvider<T> implements RandomNumberProvider<T> {
    /**
     * Random number generator.
     */
    private static final Random GENERATOR = new Random(System.currentTimeMillis());

    /**
     * Minimum value for numbers. If unspecified the minimum supported value for the number type will be used.
     */
    @Nonnull
    private T minValue;
    /**
     * Maximum value for numbers. If unspecified the maximum supported value for the number type will be used.
     */
    @Nonnull
    private T maxValue;
    /**
     * Reference for the type of random numbers to provide.
     */
    @Nonnull
    private final RandomNumberType<T> numberType;

    /**
     * <p>
     * Creates a random number provider bound to a specific type of numbers.
     * </p>
     *
     * @param numberType denotes the type of random numbers to provide
     */
    protected AbstractRandomNumberProvider(@Nonnull final RandomNumberType<T> numberType) {
        checkNotNull(numberType, "Number Type must not be null.");
        this.numberType = numberType;
        this.maxValue = numberType.max();
        this.minValue = numberType.min();
    }

    @Override
    public RandomNumberProvider<T> min(@Nullable final T minValue) {
        if (minValue == null) {
            this.minValue = numberType.min();
        } else {
            this.minValue = minValue;
        }
        return this;
    }

    @Override
    public RandomNumberProvider<T> max(@Nullable final T maxValue) {
        if (maxValue == null) {
            this.maxValue = numberType.max();
        } else {
            this.maxValue = maxValue;
        }
        return this;
    }

    @Override
    public T get() throws DataProvidingException {
        try {
            return nextRandom(Range.closed(minValue, maxValue));
        } catch (IllegalArgumentException e) {
            throw new DataProvidingException("Illegal range.", e);
        }
    }

    /**
     * Provide a random number in the given range.
     * @param range (closed) range in which to choose a number from
     * @return random value
     * @throws IllegalStateException if range is empty
     */
    private T nextRandom(final Range<T> range) {
        checkState(!range.isEmpty(), "Range must not be empty.");
        final T lowerEndpoint = range.lowerEndpoint();
        final T upperEndpoint = range.upperEndpoint();
        final double random = nextRandomRatio();
        return numberType.sum(numberType.percentOf(random, upperEndpoint),
                numberType.percentOf((1d - random), lowerEndpoint));
    }

    /**
     * <p>
     *   Return the number type used for random number generation.
     * </p>
     * @return random number type
     */
    @Nonnull
    public final RandomNumberType<T> getNumberType() {
        return numberType;
    }

    @VisibleForTesting
    double nextRandomRatio() {
        return GENERATOR.nextDouble();
    }

    @Override
    public String toString() {
        return MoreObjects.toStringHelper(this).add("numberType", numberType).add("minValue", minValue)
                .add("maxValue", maxValue).toString();
    }
}