1/* Copyright (C) 2003 Vladimir Roubtsov. All rights reserved.
2 *
3 * This program and the accompanying materials are made available under
4 * the terms of the Common Public License v1.0 which accompanies this distribution,
5 * and is available at http://www.eclipse.org/legal/cpl-v10.html
6 *
7 * $Id: Method_info.java,v 1.1.1.1 2004/05/09 16:57:47 vlad_r Exp $
8 */
9package com.vladium.jcd.cls;
10
11import java.io.IOException;
12
13import com.vladium.jcd.cls.attribute.*;
14import com.vladium.jcd.cls.constant.CONSTANT_Utf8_info;
15import com.vladium.jcd.lib.UDataInputStream;
16import com.vladium.jcd.lib.UDataOutputStream;
17
18// ----------------------------------------------------------------------------
19/**
20 * Each class method, and each instance initialization method <init>, is described
21 * by a variable-length method_info structure. The structure has the following
22 * format:
23 * <PRE>
24 *  method_info {
25 *          u2 access_flags;
26 *          u2 name_index;
27 *          u2 descriptor_index;
28 *          u2 attributes_count;
29 *          attribute_info attributes[attributes_count];
30 *  }
31 * </PRE>
32 *
33 * The value of the access_flags item is a mask of modifiers used to describe
34 * access permission to and properties of a method or instance initialization method.<P>
35 *
36 * The value of the name_index item must be a valid index into the constant pool
37 * table. The constant pool entry at that index must be a {@link CONSTANT_Utf8_info}
38 * structure representing either one of the special internal method names, either
39 * &lt;init&gt; or &lt;clinit&gt;, or a valid Java method name, stored as a simple
40 * (not fully qualified) name.<P>
41 *
42 * The value of the descriptor_index item must be a valid index into the constant pool
43 * table. The constant pool entry at that index must be a {@link CONSTANT_Utf8_info}
44 * structure representing a valid Java method descriptor.<P>
45 *
46 * Each value of the attributes table must be a variable-length attribute structure.
47 * A method can have any number of optional attributes associated with it. The only
48 * attributes defined by this specification for the attributes table of a method_info
49 * structure are the Code and Exceptions attributes. See {@link CodeAttribute_info}
50 * and {@link ExceptionsAttribute_info}.
51 *
52 * @author (C) 2001, Vlad Roubtsov
53 */
54public
55final class Method_info implements Cloneable, IAccessFlags
56{
57    // public: ................................................................
58
59
60    public int m_name_index;
61    public int m_descriptor_index;
62
63
64    public Method_info (int access_flags, int name_index, int descriptor_index, IAttributeCollection attributes)
65    {
66        m_access_flags = access_flags;
67
68        m_name_index = name_index;
69        m_descriptor_index = descriptor_index;
70
71        m_attributes = attributes;
72    }
73
74
75    public Method_info (final IConstantCollection constants,
76                        final UDataInputStream bytes)
77        throws IOException
78    {
79        m_access_flags = bytes.readU2 ();
80
81        m_name_index = bytes.readU2 ();
82        m_descriptor_index = bytes.readU2 ();
83
84        // TODO: put this logic into AttributeCollection
85
86        final int attributes_count = bytes.readU2 ();
87        m_attributes = ElementFactory.newAttributeCollection (attributes_count);
88
89        for (int i = 0; i < attributes_count; ++ i)
90        {
91            final Attribute_info attribute_info = Attribute_info.new_Attribute_info (constants, bytes);
92
93            m_attributes.add (attribute_info);
94        }
95    }
96
97    /**
98     * Returns the method name within the context of 'cls' class definition.
99     *
100     * @param cls class that contains this method
101     * @return method name
102     */
103    public String getName (final ClassDef cls)
104    {
105        return ((CONSTANT_Utf8_info) cls.getConstants ().get (m_name_index)).m_value;
106    }
107
108    /**
109     * Returns the descriptor string for this method within the context of 'cls'
110     * class definition.
111     *
112     * @param cls class that contains this method
113     * @return field typename descriptor
114     */
115    public String getDescriptor (final ClassDef cls)
116    {
117        return ((CONSTANT_Utf8_info) cls.getConstants ().get (m_descriptor_index)).m_value;
118    }
119
120    public boolean isNative ()
121    {
122        return (m_access_flags & ACC_NATIVE) != 0;
123    }
124
125    public boolean isAbstract ()
126    {
127        return (m_access_flags & ACC_ABSTRACT) != 0;
128    }
129
130    public boolean isSynthetic ()
131    {
132        return m_attributes.hasSynthetic ();
133    }
134
135    public boolean isBridge ()
136    {
137        return ((m_access_flags & ACC_BRIDGE) != 0) || m_attributes.hasBridge ();
138    }
139
140    // IAccessFlags:
141
142    public final void setAccessFlags (final int flags)
143    {
144        m_access_flags = flags;
145    }
146
147    public final int getAccessFlags ()
148    {
149        return m_access_flags;
150    }
151
152
153    public IAttributeCollection getAttributes ()
154    {
155        return m_attributes;
156    }
157
158
159    public String toString ()
160    {
161        StringBuffer s = new StringBuffer ();
162
163        s.append ("method_info: [modifiers: 0x" + Integer.toHexString(m_access_flags) + ", name_index = " + m_name_index + ", descriptor_index = " + m_descriptor_index + "]\n");
164        for (int i = 0; i < m_attributes.size (); i++)
165        {
166            Attribute_info attribute_info = m_attributes.get (i);
167
168            s.append ("\t[" + i + "] attribute: " + attribute_info + "\n");
169        }
170
171        return s.toString ();
172    }
173
174
175    // Cloneable:
176
177    /**
178     * Performs a deep copy.
179     */
180    public Object clone ()
181    {
182        try
183        {
184            final Method_info _clone = (Method_info) super.clone ();
185
186            // do deep copy:
187            _clone.m_attributes = (IAttributeCollection) m_attributes.clone ();
188
189            return _clone;
190        }
191        catch (CloneNotSupportedException e)
192        {
193            throw new InternalError (e.toString ());
194        }
195    }
196
197    // IClassFormatOutput:
198
199    public void writeInClassFormat (final UDataOutputStream out) throws IOException
200    {
201        out.writeU2 (m_access_flags);
202
203        out.writeU2 (m_name_index);
204        out.writeU2 (m_descriptor_index);
205
206        m_attributes.writeInClassFormat (out);
207    }
208
209    // protected: .............................................................
210
211    // package: ...............................................................
212
213    // private: ...............................................................
214
215
216    private int m_access_flags;
217    private IAttributeCollection m_attributes;
218
219} // end of class
220// ----------------------------------------------------------------------------
221