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1   /*
2    * Copyright (C) 2007 The Guava Authors
3    *
4    * Licensed under the Apache License, Version 2.0 (the "License");
5    * you may not use this file except in compliance with the License.
6    * You may obtain a copy of the License at
7    *
8    * http://www.apache.org/licenses/LICENSE-2.0
9    *
10   * Unless required by applicable law or agreed to in writing, software
11   * distributed under the License is distributed on an "AS IS" BASIS,
12   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13   * See the License for the specific language governing permissions and
14   * limitations under the License.
15   */
16  
17  package com.google.common.collect;
18  
19  import com.google.common.annotations.GwtCompatible;
20  import java.io.Serializable;
21  
22  /**
23   * An ordering that uses the natural order of the string representation of the
24   * values.
25   */
26  @GwtCompatible(serializable = true)
27  final class UsingToStringOrdering extends Ordering<Object> implements Serializable {
28    static final UsingToStringOrdering INSTANCE = new UsingToStringOrdering();
29  
30    @Override
31    public int compare(Object left, Object right) {
32      return left.toString().compareTo(right.toString());
33    }
34  
35    // preserve singleton-ness, so equals() and hashCode() work correctly
36    private Object readResolve() {
37      return INSTANCE;
38    }
39  
40    @Override
41    public String toString() {
42      return "Ordering.usingToString()";
43    }
44  
45    private UsingToStringOrdering() {}
46  
47    private static final long serialVersionUID = 0;
48  }