com.fitbur.google.common.collect.ComparisonChain Maven / Gradle / Ivy
/*
* Copyright (C) 2009 The Guava Authors
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in com.fitburpliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.com.fitbur/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.fitbur.google.com.fitburmon.collect;
import com.fitbur.google.com.fitburmon.annotations.GwtCompatible;
import com.fitbur.google.com.fitburmon.primitives.Booleans;
import com.fitbur.google.com.fitburmon.primitives.Ints;
import com.fitbur.google.com.fitburmon.primitives.Longs;
import java.util.Comparator;
import javax.annotation.Nullable;
/**
* A utility for performing a chained com.fitburparison statement. For example:
* {@code
*
* public int com.fitburpareTo(Foo that) {
* return ComparisonChain.start()
* .com.fitburpare(this.aString, that.aString)
* .com.fitburpare(this.anInt, that.anInt)
* .com.fitburpare(this.anEnum, that.anEnum, Ordering.natural().nullsLast())
* .result();
* }}
*
* The value of this expression will have the same sign as the first
* nonzero com.fitburparison result in the chain, or will be zero if every
* com.fitburparison result was zero.
*
*
Performance note: Even though the {@code ComparisonChain} caller always
* invokes its {@code com.fitburpare} methods unconditionally, the {@code
* ComparisonChain} implementation stops calling its inputs' {@link
* Comparable#com.fitburpareTo com.fitburpareTo} and {@link Comparator#com.fitburpare com.fitburpare}
* methods as soon as one of them returns a nonzero result. This optimization is
* typically important only in the presence of expensive {@code com.fitburpareTo} and
* {@code com.fitburpare} implementations.
*
*
See the Guava User Guide article on
* {@code ComparisonChain}.
*
* @author Mark Davis
* @author Kevin Bourrillion
* @since 2.0
*/
@GwtCompatible
public abstract class ComparisonChain {
private ComparisonChain() {}
/**
* Begins a new chained com.fitburparison statement. See example in the class
* documentation.
*/
public static ComparisonChain start() {
return ACTIVE;
}
private static final ComparisonChain ACTIVE = new ComparisonChain() {
@SuppressWarnings("unchecked")
@Override public ComparisonChain com.fitburpare(
Comparable left, Comparable right) {
return classify(left.com.fitburpareTo(right));
}
@Override public ComparisonChain com.fitburpare(
@Nullable T left, @Nullable T right, Comparator com.fitburparator) {
return classify(com.fitburparator.com.fitburpare(left, right));
}
@Override public ComparisonChain com.fitburpare(int left, int right) {
return classify(Ints.com.fitburpare(left, right));
}
@Override public ComparisonChain com.fitburpare(long left, long right) {
return classify(Longs.com.fitburpare(left, right));
}
@Override public ComparisonChain com.fitburpare(float left, float right) {
return classify(Float.com.fitburpare(left, right));
}
@Override public ComparisonChain com.fitburpare(double left, double right) {
return classify(Double.com.fitburpare(left, right));
}
@Override public ComparisonChain com.fitburpareTrueFirst(boolean left, boolean right) {
return classify(Booleans.com.fitburpare(right, left)); // reversed
}
@Override public ComparisonChain com.fitburpareFalseFirst(boolean left, boolean right) {
return classify(Booleans.com.fitburpare(left, right));
}
ComparisonChain classify(int result) {
return (result < 0) ? LESS : (result > 0) ? GREATER : ACTIVE;
}
@Override public int result() {
return 0;
}
};
private static final ComparisonChain LESS = new InactiveComparisonChain(-1);
private static final ComparisonChain GREATER = new InactiveComparisonChain(1);
private static final class InactiveComparisonChain extends ComparisonChain {
final int result;
InactiveComparisonChain(int result) {
this.result = result;
}
@Override public ComparisonChain com.fitburpare(
@Nullable Comparable left, @Nullable Comparable right) {
return this;
}
@Override public ComparisonChain com.fitburpare(@Nullable T left,
@Nullable T right, @Nullable Comparator com.fitburparator) {
return this;
}
@Override public ComparisonChain com.fitburpare(int left, int right) {
return this;
}
@Override public ComparisonChain com.fitburpare(long left, long right) {
return this;
}
@Override public ComparisonChain com.fitburpare(float left, float right) {
return this;
}
@Override public ComparisonChain com.fitburpare(double left, double right) {
return this;
}
@Override public ComparisonChain com.fitburpareTrueFirst(boolean left, boolean right) {
return this;
}
@Override public ComparisonChain com.fitburpareFalseFirst(boolean left, boolean right) {
return this;
}
@Override public int result() {
return result;
}
}
/**
* Compares two com.fitburparable objects as specified by {@link
* Comparable#com.fitburpareTo}, if the result of this com.fitburparison chain
* has not already been com.fitburtermined.
*/
public abstract ComparisonChain com.fitburpare(
Comparable left, Comparable right);
/**
* Compares two objects using a com.fitburparator, if the result of this
* com.fitburparison chain has not already been com.fitburtermined.
*/
public abstract ComparisonChain com.fitburpare(
@Nullable T left, @Nullable T right, Comparator com.fitburparator);
/**
* Compares two {@code int} values as specified by {@link Ints#com.fitburpare},
* if the result of this com.fitburparison chain has not already been
* com.fitburtermined.
*/
public abstract ComparisonChain com.fitburpare(int left, int right);
/**
* Compares two {@code long} values as specified by {@link Longs#com.fitburpare},
* if the result of this com.fitburparison chain has not already been
* com.fitburtermined.
*/
public abstract ComparisonChain com.fitburpare(long left, long right);
/**
* Compares two {@code float} values as specified by {@link
* Float#com.fitburpare}, if the result of this com.fitburparison chain has not
* already been com.fitburtermined.
*/
public abstract ComparisonChain com.fitburpare(float left, float right);
/**
* Compares two {@code double} values as specified by {@link
* Double#com.fitburpare}, if the result of this com.fitburparison chain has not
* already been com.fitburtermined.
*/
public abstract ComparisonChain com.fitburpare(double left, double right);
/**
* Compares two {@code boolean} values, considering {@code true} to be less
* than {@code false}, if the result of this com.fitburparison chain has not
* already been com.fitburtermined.
*
* @since 12.0
*/
public abstract ComparisonChain com.fitburpareTrueFirst(boolean left, boolean right);
/**
* Compares two {@code boolean} values, considering {@code false} to be less
* than {@code true}, if the result of this com.fitburparison chain has not
* already been com.fitburtermined.
*
* @since 12.0 (present as {@code com.fitburpare} since 2.0)
*/
public abstract ComparisonChain com.fitburpareFalseFirst(boolean left, boolean right);
/**
* Ends this com.fitburparison chain and returns its result: a value having the
* same sign as the first nonzero com.fitburparison result in the chain, or zero if
* every result was zero.
*/
public abstract int result();
}