1 /*
2  * Copyright (C) 2007 The Android Open Source Project
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.android.dexgen.rop.cst;
18 
19 import com.android.dexgen.util.ToHuman;
20 
21 /**
22  * Base class for constants of all sorts.
23  */
24 public abstract class Constant
25         implements ToHuman, Comparable<Constant> {
26     /**
27      * Returns {@code true} if this instance is a category-2 constant,
28      * meaning it takes up two slots in the constant pool, or
29      * {@code false} if this instance is category-1.
30      *
31      * @return {@code true} iff this instance is category-2
32      */
isCategory2()33     public abstract boolean isCategory2();
34 
35     /**
36      * Returns the human name for the particular type of constant
37      * this instance is.
38      *
39      * @return {@code non-null;} the name
40      */
typeName()41     public abstract String typeName();
42 
43     /**
44      * {@inheritDoc}
45      *
46      * This compares in class-major and value-minor order.
47      */
compareTo(Constant other)48     public final int compareTo(Constant other) {
49         Class clazz = getClass();
50         Class otherClazz = other.getClass();
51 
52         if (clazz != otherClazz) {
53             return clazz.getName().compareTo(otherClazz.getName());
54         }
55 
56         return compareTo0(other);
57     }
58 
59     /**
60      * Compare the values of this and another instance, which are guaranteed
61      * to be of the same class. Subclasses must implement this.
62      *
63      * @param other {@code non-null;} the instance to compare to
64      * @return {@code -1}, {@code 0}, or {@code 1}, as usual
65      * for a comparison
66      */
compareTo0(Constant other)67     protected abstract int compareTo0(Constant other);
68 }
69