/*
* 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 static com.google.common.base.
Preconditions.checkNotNull;
import com.google.common.annotations.
GwtCompatible;
import java.io.
Serializable;
import java.util.
Iterator;
import javax.annotation.
Nullable;
/** An ordering that uses the reverse of a given order. */
@
GwtCompatible(serializable = true)
final class
ReverseOrdering<T> extends
Ordering<T> implements
Serializable {
final
Ordering<? super T>
forwardOrder;
ReverseOrdering(
Ordering<? super T>
forwardOrder) {
this.
forwardOrder =
checkNotNull(
forwardOrder);
}
@
Override public int
compare(T
a, T
b) {
return
forwardOrder.
compare(
b,
a);
}
@
SuppressWarnings("unchecked") // how to explain?
@
Override public <S extends T>
Ordering<S>
reverse() {
return (
Ordering<S>)
forwardOrder;
}
// Override the min/max methods to "hoist" delegation outside loops
@
Override public <E extends T> E
min(E
a, E
b) {
return
forwardOrder.
max(
a,
b);
}
@
Override public <E extends T> E
min(E
a, E
b, E
c, E...
rest) {
return
forwardOrder.
max(
a,
b,
c,
rest);
}
@
Override public <E extends T> E
min(
Iterator<E>
iterator) {
return
forwardOrder.
max(
iterator);
}
@
Override public <E extends T> E
min(
Iterable<E>
iterable) {
return
forwardOrder.
max(
iterable);
}
@
Override public <E extends T> E
max(E
a, E
b) {
return
forwardOrder.
min(
a,
b);
}
@
Override public <E extends T> E
max(E
a, E
b, E
c, E...
rest) {
return
forwardOrder.
min(
a,
b,
c,
rest);
}
@
Override public <E extends T> E
max(
Iterator<E>
iterator) {
return
forwardOrder.
min(
iterator);
}
@
Override public <E extends T> E
max(
Iterable<E>
iterable) {
return
forwardOrder.
min(
iterable);
}
@
Override public int
hashCode() {
return -
forwardOrder.
hashCode();
}
@
Override public boolean
equals(@
Nullable Object object) {
if (
object == this) {
return true;
}
if (
object instanceof
ReverseOrdering) {
ReverseOrdering<?>
that = (
ReverseOrdering<?>)
object;
return this.
forwardOrder.
equals(
that.
forwardOrder);
}
return false;
}
@
Override public
String toString() {
return
forwardOrder + ".reverse()";
}
private static final long
serialVersionUID = 0;
}