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.dex.file;
18 
19 import com.android.dexgen.util.AnnotatedOutput;
20 
21 /**
22  * Base class for any structurally-significant and (potentially)
23  * repeated piece of a Dalvik file.
24  */
25 public abstract class Item {
26     /**
27      * Constructs an instance.
28      */
Item()29     public Item() {
30         // This space intentionally left blank.
31     }
32 
33     /**
34      * Returns the item type for this instance.
35      *
36      * @return {@code non-null;} the item type
37      */
itemType()38     public abstract ItemType itemType();
39 
40     /**
41      * Returns the human name for the particular type of item this
42      * instance is.
43      *
44      * @return {@code non-null;} the name
45      */
typeName()46     public final String typeName() {
47         return itemType().toHuman();
48     }
49 
50     /**
51      * Gets the size of this instance when written, in bytes.
52      *
53      * @return {@code >= 0;} the write size
54      */
writeSize()55     public abstract int writeSize();
56 
57     /**
58      * Populates a {@link DexFile} with items from within this instance.
59      * This will <i>not</i> add an item to the file for this instance itself
60      * (which should have been done by whatever refers to this instance).
61      *
62      * <p><b>Note:</b> Subclasses must override this to do something
63      * appropriate.</p>
64      *
65      * @param file {@code non-null;} the file to populate
66      */
addContents(DexFile file)67     public abstract void addContents(DexFile file);
68 
69     /**
70      * Writes the representation of this instance to the given data section,
71      * using the given {@link DexFile} to look things up as needed.
72      * If this instance keeps track of its offset, then this method will
73      * note the written offset and will also throw an exception if this
74      * instance has already been written.
75      *
76      * @param file {@code non-null;} the file to use for reference
77      * @param out {@code non-null;} where to write to
78      */
writeTo(DexFile file, AnnotatedOutput out)79     public abstract void writeTo(DexFile file, AnnotatedOutput out);
80 }
81