org.springframework.util.comparator.BooleanComparator Maven / Gradle / Ivy
/*
* Copyright 2002-2018 the original author or 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
*
* https://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.springframework.util.comparator;
import java.io.Serializable;
import java.util.Comparator;
import org.springframework.lang.Nullable;
/**
* A {@link Comparator} for {@link Boolean} objects that can sort either
* {@code true} or {@code false} first.
*
* @author Keith Donald
* @since 1.2.2
*/
@SuppressWarnings("serial")
public class BooleanComparator implements Comparator, Serializable {
/**
* A shared default instance of this comparator,
* treating {@code true} lower than {@code false}.
*/
public static final BooleanComparator TRUE_LOW = new BooleanComparator(true);
/**
* A shared default instance of this comparator,
* treating {@code true} higher than {@code false}.
*/
public static final BooleanComparator TRUE_HIGH = new BooleanComparator(false);
private final boolean trueLow;
/**
* Create a BooleanComparator that sorts boolean values based on
* the provided flag.
* Alternatively, you can use the default shared instances:
* {@code BooleanComparator.TRUE_LOW} and
* {@code BooleanComparator.TRUE_HIGH}.
* @param trueLow whether to treat true as lower or higher than false
* @see #TRUE_LOW
* @see #TRUE_HIGH
*/
public BooleanComparator(boolean trueLow) {
this.trueLow = trueLow;
}
@Override
public int compare(Boolean v1, Boolean v2) {
return (v1 ^ v2) ? ((v1 ^ this.trueLow) ? 1 : -1) : 0;
}
@Override
public boolean equals(@Nullable Object other) {
return (this == other || (other instanceof BooleanComparator &&
this.trueLow == ((BooleanComparator) other).trueLow));
}
@Override
public int hashCode() {
return getClass().hashCode() * (this.trueLow ? -1 : 1);
}
@Override
public String toString() {
return "BooleanComparator: " + (this.trueLow ? "true low" : "true high");
}
}