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  
21  import java.io.Serializable;
22  
23  /**
24   * An ordering that uses the natural order of the string representation of the
25   * values.
26   */
27  @GwtCompatible(serializable = true)
28  final class UsingToStringOrdering
29      extends Ordering<Object> implements Serializable {
30    static final UsingToStringOrdering INSTANCE = new UsingToStringOrdering();
31  
32    @Override public int compare(Object left, Object right) {
33      return left.toString().compareTo(right.toString());
34    }
35  
36    // preserve singleton-ness, so equals() and hashCode() work correctly
37    private Object readResolve() {
38      return INSTANCE;
39    }
40  
41    @Override public String toString() {
42      return "Ordering.usingToString()";
43    }
44  
45    private UsingToStringOrdering() {}
46  
47    private static final long serialVersionUID = 0;
48  }