com.google.common.collect.ExplicitOrdering Maven / Gradle / Ivy
/*
* Copyright (C) 2007 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.GwtCompatible;
import java.io.Serializable;
import java.util.List;
/** An ordering that compares objects according to a given order. */
@GwtCompatible(serializable = true)
final class ExplicitOrdering extends Ordering implements Serializable {
final ImmutableMap rankMap;
ExplicitOrdering(List valuesInOrder) {
this(Maps.indexMap(valuesInOrder));
}
ExplicitOrdering(ImmutableMap rankMap) {
this.rankMap = rankMap;
}
@Override
public int compare(T left, T right) {
return rank(left) - rank(right); // safe because both are nonnegative
}
private int rank(T value) {
Integer rank = rankMap.get(value);
if (rank == null) {
throw new IncomparableValueException(value);
}
return rank;
}
@Override
public boolean equals(Object object) {
if (object instanceof ExplicitOrdering) {
ExplicitOrdering that = (ExplicitOrdering) object;
return this.rankMap.equals(that.rankMap);
}
return false;
}
@Override
public int hashCode() {
return rankMap.hashCode();
}
@Override
public String toString() {
return "Ordering.explicit(" + rankMap.keySet() + ")";
}
private static final long serialVersionUID = 0;
}