LegacyComparable.java revision 1d580d0f6ee4f21eb309ba7b509d2c6d671c4044 
1/*
2 * Copyright (C) 2009 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
17package com.google.common.collect;
18
19import com.google.common.annotations.GwtCompatible;
20
21import java.io.Serializable;
22import java.util.Arrays;
23
24/**
25 * A class that implements {@code Comparable} without generics, such as those
26 * found in libraries that support Java 1.4 and before. Our library needs to
27 * do the bare minimum to accommodate such types, though their use may still
28 * require an explicit type parameter and/or warning suppression.
29 *
30 * @author Kevin Bourrillion
31 */
32@GwtCompatible
33class LegacyComparable implements Comparable, Serializable {
34  static final LegacyComparable X = new LegacyComparable("x");
35  static final LegacyComparable Y = new LegacyComparable("y");
36  static final LegacyComparable Z = new LegacyComparable("z");
37
38  static final Iterable<LegacyComparable> VALUES_FORWARD
39      = Arrays.asList(X, Y, Z);
40  static final Iterable<LegacyComparable> VALUES_BACKWARD
41      = Arrays.asList(Z, Y, X);
42
43  private final String value;
44
45  LegacyComparable(String value) {
46    this.value = value;
47  }
48
49  @Override
50  public int compareTo(Object object) {
51    // This method is spec'd to throw CCE if object is of the wrong type
52    LegacyComparable that = (LegacyComparable) object;
53    return this.value.compareTo(that.value);
54  }
55
56  @Override public boolean equals(Object object) {
57    if (object instanceof LegacyComparable) {
58      LegacyComparable that = (LegacyComparable) object;
59      return this.value.equals(that.value);
60    }
61    return false;
62  }
63
64  @Override public int hashCode() {
65    return value.hashCode();
66  }
67
68  private static final long serialVersionUID = 0;
69}
70