Mega Code Archive
A Comparator for Boolean objects that can sort either true or false first
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/*
* Copyright 2002-2005 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
*
* 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.
*/
import java.io.Serializable;
import java.util.Comparator;
/**
* A Comparator for Boolean objects that can sort either true or false first.
*
* @author Keith Donald
* @since 1.2.2
*/
public final class BooleanComparator implements Comparator, Serializable {
/**
* A shared default instance of this comparator, treating true lower
* than false.
*/
public static final BooleanComparator TRUE_LOW = new BooleanComparator(true);
/**
* A shared default instance of this comparator, treating true higher
* than 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.
* <p>Alternatively, you can use the default shared instances:
* <code>BooleanComparator.TRUE_LOW</code> and
* <code>BooleanComparator.TRUE_HIGH</code>.
* @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;
}
public int compare(Object o1, Object o2) {
boolean v1 = ((Boolean) o1).booleanValue();
boolean v2 = ((Boolean) o2).booleanValue();
return (v1 ^ v2) ? ((v1 ^ this.trueLow) ? 1 : -1) : 0;
}
public boolean equals(Object obj) {
if (this == obj) {
return true;
}
if (!(obj instanceof BooleanComparator)) {
return false;
}
return (this.trueLow == ((BooleanComparator) obj).trueLow);
}
public int hashCode() {
return (this.trueLow ? -1 : 1) * getClass().hashCode();
}
public String toString() {
return "BooleanComparator: " + (this.trueLow ? "true low" : "true high");
}
}
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