/*
* Copyright 2015 Red Hat, Inc. and/or its affiliates.
*
* 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.
*/
package org.optaplanner.core.impl.domain.valuerange.buildin.biginteger;
import java.math.BigInteger;
import java.util.Iterator;
import java.util.NoSuchElementException;
import java.util.Random;
import org.optaplanner.core.impl.domain.valuerange.AbstractCountableValueRange;
import org.optaplanner.core.impl.domain.valuerange.util.ValueRangeIterator;
import org.optaplanner.core.impl.solver.random.RandomUtils;
public class BigIntegerValueRange extends AbstractCountableValueRange<BigInteger> {
private final BigInteger from;
private final BigInteger to;
private final BigInteger incrementUnit;
/**
* @param from never null, inclusive minimum
* @param to never null, exclusive maximum, {@code >= from}
*/
public BigIntegerValueRange(BigInteger from, BigInteger to) {
this(from, to, BigInteger.valueOf(1L));
}
/**
* @param from never null, inclusive minimum
* @param to never null, exclusive maximum, {@code >= from}
* @param incrementUnit never null, {@code > 0}
*/
public BigIntegerValueRange(BigInteger from, BigInteger to, BigInteger incrementUnit) {
this.from = from;
this.to = to;
this.incrementUnit = incrementUnit;
if (to.compareTo(from) < 0) {
throw new IllegalArgumentException("The " + getClass().getSimpleName()
+ " cannot have a from (" + from + ") which is strictly higher than its to (" + to + ").");
}
if (incrementUnit.compareTo(BigInteger.ZERO) <= 0) {
throw new IllegalArgumentException("The " + getClass().getSimpleName()
+ " must have strictly positive incrementUnit (" + incrementUnit + ").");
}
if (!to.subtract(from).remainder(incrementUnit).equals(BigInteger.ZERO)) {
throw new IllegalArgumentException("The " + getClass().getSimpleName()
+ "'s incrementUnit (" + incrementUnit
+ ") must fit an integer number of times between from (" + from + ") and to (" + to + ").");
}
}
@Override
public long getSize() {
return to.subtract(from).divide(incrementUnit).longValue();
}
@Override
public BigInteger get(long index) {
if (index < 0L || index >= getSize()) {
throw new IndexOutOfBoundsException("The index (" + index + ") must be >= 0 and < size ("
+ getSize() + ").");
}
return incrementUnit.multiply(BigInteger.valueOf(index)).add(from);
}
@Override
public boolean contains(BigInteger value) {
if (value == null || value.compareTo(from) < 0 || value.compareTo(to) >= 0) {
return false;
}
return value.subtract(from).remainder(incrementUnit).compareTo(BigInteger.ZERO) == 0;
}
@Override
public Iterator<BigInteger> createOriginalIterator() {
return new OriginalBigIntegerValueRangeIterator();
}
private class OriginalBigIntegerValueRangeIterator extends ValueRangeIterator<BigInteger> {
private BigInteger upcoming = from;
@Override
public boolean hasNext() {
return upcoming.compareTo(to) < 0;
}
@Override
public BigInteger next() {
if (upcoming.compareTo(to) >= 0) {
throw new NoSuchElementException();
}
BigInteger next = upcoming;
upcoming = upcoming.add(incrementUnit);
return next;
}
}
@Override
public Iterator<BigInteger> createRandomIterator(Random workingRandom) {
return new RandomBigIntegerValueRangeIterator(workingRandom);
}
private class RandomBigIntegerValueRangeIterator extends ValueRangeIterator<BigInteger> {
private final Random workingRandom;
private final long size = getSize();
public RandomBigIntegerValueRangeIterator(Random workingRandom) {
this.workingRandom = workingRandom;
}
@Override
public boolean hasNext() {
return size > 0L;
}
@Override
public BigInteger next() {
if (size <= 0L) {
throw new NoSuchElementException();
}
long index = RandomUtils.nextLong(workingRandom, size);
return incrementUnit.multiply(BigInteger.valueOf(index)).add(from);
}
}
@Override
public String toString() {
return "[" + from + "-" + to + ")"; // Formatting: interval (mathematics) ISO 31-11
}
}