1 cananian 1.1.2.1 // AttributeSignature.java, created Wed Mar 27 04:23:21 2002 by cananian
2 cananian 1.1.2.1 // Copyright (C) 2002 C. Scott Ananian <cananian@alumni.princeton.edu>
3 cananian 1.1.2.1 // Licensed under the terms of the GNU GPL; see COPYING for details.
4 cananian 1.1.2.1 package harpoon.IR.RawClass;
5 cananian 1.1.2.1
6 cananian 1.1.2.1 /**
7 cananian 1.1.2.1 * Classfiles need to carry generic type information in a backwards-compatible
8 cananian 1.1.2.1 * way. This is accomplished by introducing a new "Signature" attribute for
9 cananian 1.1.2.1 * classes, methods, and fields. (GJ)
10 cananian 1.1.2.1 *
11 cananian 1.1.2.1 * @author C. Scott Ananian <cananian@alumni.princeton.edu>
12 cananian 1.3 * @version $Id: AttributeSignature.java,v 1.3 2003/09/05 21:45:16 cananian Exp $
13 cananian 1.1.2.1 * @see Attribute
14 cananian 1.1.2.1 * @see ClassFile
15 cananian 1.1.2.1 */
16 cananian 1.1.2.1 public class AttributeSignature extends Attribute {
17 cananian 1.3 /** The string naming this <code>Attribute</code> type. */
18 cananian 1.3 public static final String ATTRIBUTE_NAME = "Signature";
19 cananian 1.1.2.1 /** The value of the <code>signature_index</code> item must be a
20 cananian 1.1.2.1 valid index into the <code>constant_pool</code> table. The
21 cananian 1.1.2.1 constant pool entry at that index must be a
22 cananian 1.1.2.1 <code>CONSTANT_Utf8_info</code> structure representing the
23 cananian 1.1.2.1 string giving the name of the GJ signature for this method,
24 cananian 1.1.2.1 field, or class. */
25 cananian 1.1.2.1 public int signature_index;
26 cananian 1.1.2.1
27 cananian 1.1.2.1 /** Creates a <code>AttributeSignature</code>. */
28 cananian 1.1.2.1 AttributeSignature(ClassFile parent, ClassDataInputStream in,
29 cananian 1.1.2.1 int attribute_name_index) throws java.io.IOException {
30 cananian 1.1.2.1 super(parent, attribute_name_index);
31 cananian 1.1.2.1 long attribute_length = in.read_u4();
32 cananian 1.1.2.1 if (attribute_length != 2)
33 cananian 1.1.2.1 throw new ClassDataException("Signature attribute with length "
34 cananian 1.1.2.1 + attribute_length);
35 cananian 1.1.2.1 signature_index = in.read_u2();
36 cananian 1.3 assert ATTRIBUTE_NAME.equals(attribute_name());
37 cananian 1.1.2.1 }
38 cananian 1.1.2.1 /** Constructor. */
39 cananian 1.1.2.1 public AttributeSignature(ClassFile parent, int attribute_name_index,
40 cananian 1.1.2.1 int signature_index) {
41 cananian 1.1.2.1 super(parent, attribute_name_index);
42 cananian 1.1.2.1 this.signature_index = signature_index;
43 cananian 1.3 assert ATTRIBUTE_NAME.equals(attribute_name());
44 cananian 1.1.2.1 }
45 cananian 1.1.2.1 public long attribute_length() { return 2; }
46 cananian 1.1.2.1
47 cananian 1.1.2.1 // convenience
48 cananian 1.1.2.1 public ConstantUtf8 signature_index()
49 cananian 1.1.2.1 { return (ConstantUtf8) parent.constant_pool[signature_index]; }
50 cananian 1.1.2.1 public String signature() { return signature_index().val; }
51 cananian 1.1.2.1
52 cananian 1.1.2.1 /** Write to bytecode stream. */
53 cananian 1.1.2.1 public void write(ClassDataOutputStream out) throws java.io.IOException {
54 cananian 1.1.2.1 out.write_u2(attribute_name_index);
55 cananian 1.1.2.1 out.write_u4(attribute_length());
56 cananian 1.1.2.1 out.write_u2(signature_index);
57 cananian 1.1.2.1 }
58 cananian 1.1.2.1
59 cananian 1.1.2.1 /** Pretty-print this attribute structure.
60 cananian 1.1.2.1 * @param indent the indentation level to use.
61 cananian 1.1.2.1 */
62 cananian 1.1.2.1 public void print(java.io.PrintWriter pw, int indent) {
63 cananian 1.1.2.1 indent(pw, indent, "Signature Attribute: " +
64 cananian 1.1.2.1 signature() + " {" + signature_index + "}");
65 cananian 1.1.2.1 }
66 cananian 1.2 }