81 lines
2.2 KiB
Java
81 lines
2.2 KiB
Java
/*
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* Copyright (C) 2007 The Guava Authors
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package com.google.common.collect;
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import java.io.Serializable;
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import java.util.Iterator;
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import javax.annotation.Nullable;
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import com.google.common.annotations.GwtCompatible;
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/**
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* An ordering which sorts iterables by comparing corresponding elements
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* pairwise.
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*/
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@GwtCompatible(serializable = true)
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final class LexicographicalOrdering<T> extends Ordering<Iterable<T>> implements Serializable {
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final Ordering<? super T> elementOrder;
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LexicographicalOrdering(Ordering<? super T> elementOrder) {
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this.elementOrder = elementOrder;
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}
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@Override
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public int compare(Iterable<T> leftIterable, Iterable<T> rightIterable) {
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Iterator<T> left = leftIterable.iterator();
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Iterator<T> right = rightIterable.iterator();
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while (left.hasNext()) {
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if (!right.hasNext()) {
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return LEFT_IS_GREATER; // because it's longer
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}
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int result = elementOrder.compare(left.next(), right.next());
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if (result != 0) {
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return result;
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}
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}
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if (right.hasNext()) {
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return RIGHT_IS_GREATER; // because it's longer
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}
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return 0;
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}
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@Override
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public boolean equals(@Nullable Object object) {
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if (object == this) {
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return true;
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}
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if (object instanceof LexicographicalOrdering) {
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LexicographicalOrdering<?> that = (LexicographicalOrdering<?>) object;
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return this.elementOrder.equals(that.elementOrder);
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}
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return false;
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}
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@Override
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public int hashCode() {
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return elementOrder.hashCode() ^ 2075626741; // meaningless
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}
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@Override
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public String toString() {
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return elementOrder + ".lexicographical()";
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}
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private static final long serialVersionUID = 0;
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}
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