/*
* Copyright (C) 2010 The Guava Authors
*
* 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 com.google.common.collect;
import com.google.common.annotations.Beta;
import com.google.common.annotations.GwtCompatible;
import java.io.Serializable;
import java.math.BigInteger;
/**
* Factories for common {@link DiscreteDomain} instances.
*
* @author Gregory Kick
* @since 10.0
*/
@GwtCompatible
@Beta
public final class DiscreteDomains {
private DiscreteDomains() {}
/**
* Returns the discrete domain for values of type {@code Integer}.
*/
public static DiscreteDomain<Integer> integers() {
return IntegerDomain.INSTANCE;
}
private static final class IntegerDomain extends DiscreteDomain<Integer>
implements Serializable {
private static final IntegerDomain INSTANCE = new IntegerDomain();
@Override public Integer next(Integer value) {
int i = value;
return (i == Integer.MAX_VALUE) ? null : i + 1;
}
@Override public Integer previous(Integer value) {
int i = value;
return (i == Integer.MIN_VALUE) ? null : i - 1;
}
@Override public long distance(Integer start, Integer end) {
return (long) end - start;
}
@Override public Integer minValue() {
return Integer.MIN_VALUE;
}
@Override public Integer maxValue() {
return Integer.MAX_VALUE;
}
private Object readResolve() {
return INSTANCE;
}
private static final long serialVersionUID = 0;
}
/**
* Returns the discrete domain for values of type {@code Long}.
*/
public static DiscreteDomain<Long> longs() {
return LongDomain.INSTANCE;
}
private static final class LongDomain extends DiscreteDomain<Long>
implements Serializable {
private static final LongDomain INSTANCE = new LongDomain();
@Override public Long next(Long value) {
long l = value;
return (l == Long.MAX_VALUE) ? null : l + 1;
}
@Override public Long previous(Long value) {
long l = value;
return (l == Long.MIN_VALUE) ? null : l - 1;
}
@Override public long distance(Long start, Long end) {
long result = end - start;
if (end > start && result < 0) { // overflow
return Long.MAX_VALUE;
}
if (end < start && result > 0) { // underflow
return Long.MIN_VALUE;
}
return result;
}
@Override public Long minValue() {
return Long.MIN_VALUE;
}
@Override public Long maxValue() {
return Long.MAX_VALUE;
}
private Object readResolve() {
return INSTANCE;
}
private static final long serialVersionUID = 0;
}
/**
* Returns the discrete domain for values of type {@code BigInteger}.
*/
// TODO(kevinb): make sure it's tested, and make it public
static DiscreteDomain<BigInteger> bigIntegers() {
return BigIntegerDomain.INSTANCE;
}
private static final class BigIntegerDomain extends DiscreteDomain<BigInteger>
implements Serializable {
private static final BigIntegerDomain INSTANCE = new BigIntegerDomain();
private static final BigInteger MIN_LONG =
BigInteger.valueOf(Long.MIN_VALUE);
private static final BigInteger MAX_LONG =
BigInteger.valueOf(Long.MAX_VALUE);
@Override public BigInteger next(BigInteger value) {
return value.add(BigInteger.ONE);
}
@Override public BigInteger previous(BigInteger value) {
return value.subtract(BigInteger.ONE);
}
@Override public long distance(BigInteger start, BigInteger end) {
return start.subtract(end).max(MIN_LONG).min(MAX_LONG).longValue();
}
private Object readResolve() {
return INSTANCE;
}
private static final long serialVersionUID = 0;
}
}
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