1 package org.apache.bcel.generic;
2
3 /* ====================================================================
4 * The Apache Software License, Version 1.1
5 *
6 * Copyright (c) 2001 The Apache Software Foundation. All rights
7 * reserved.
8 *
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
11 * are met:
12 *
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 *
16 * 2. Redistributions in binary form must reproduce the above copyright
17 * notice, this list of conditions and the following disclaimer in
18 * the documentation and/or other materials provided with the
19 * distribution.
20 *
21 * 3. The end-user documentation included with the redistribution,
22 * if any, must include the following acknowledgment:
23 * "This product includes software developed by the
24 * Apache Software Foundation (http://www.apache.org/)."
25 * Alternately, this acknowledgment may appear in the software itself,
26 * if and wherever such third-party acknowledgments normally appear.
27 *
28 * 4. The names "Apache" and "Apache Software Foundation" and
29 * "Apache BCEL" must not be used to endorse or promote products
30 * derived from this software without prior written permission. For
31 * written permission, please contact apache@apache.org.
32 *
33 * 5. Products derived from this software may not be called "Apache",
34 * "Apache BCEL", nor may "Apache" appear in their name, without
35 * prior written permission of the Apache Software Foundation.
36 *
37 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
38 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
39 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
40 * DISCLAIMED. IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
41 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
42 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
43 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
44 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
45 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
46 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
47 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
48 * SUCH DAMAGE.
49 * ====================================================================
50 *
51 * This software consists of voluntary contributions made by many
52 * individuals on behalf of the Apache Software Foundation. For more
53 * information on the Apache Software Foundation, please see
54 * <http://www.apache.org/>.
55 */
56
57 import org.apache.bcel.Constants;
58 import org.apache.bcel.classfile.*;
59 import java.util.ArrayList;
60 import java.util.Iterator;
61
62 /***
63 * Template class for building up a field. The only extraordinary thing
64 * one can do is to add a constant value attribute to a field (which must of
65 * course be compatible with to the declared type).
66 *
67 * @version $Id: FieldGen.java,v 1.1.1.1 2001/10/29 20:00:12 jvanzyl Exp $
68 * @author <A HREF="mailto:markus.dahm@berlin.de">M. Dahm</A>
69 * @see Field
70 */
71 public class FieldGen extends FieldGenOrMethodGen {
72 private Object value = null;
73
74 /***
75 * Declare a field. If it is static (isStatic() == true) and has a
76 * basic type like int or String it may have an initial value
77 * associated with it as defined by setInitValue().
78 *
79 * @param access_flags access qualifiers
80 * @param type field type
81 * @param name field name
82 * @param cp constant pool
83 */
84 public FieldGen(int access_flags, Type type, String name, ConstantPoolGen cp) {
85 setAccessFlags(access_flags);
86 setType(type);
87 setName(name);
88 setConstantPool(cp);
89 }
90
91 /***
92 * Instantiate from existing field.
93 *
94 * @param field Field object
95 * @param cp constant pool (must contain the same entries as the field's constant pool)
96 */
97 public FieldGen(Field field, ConstantPoolGen cp) {
98 this(field.getAccessFlags(), Type.getType(field.getSignature()), field.getName(), cp);
99
100 Attribute[] attrs = field.getAttributes();
101
102 for(int i=0; i < attrs.length; i++) {
103 if(attrs[i] instanceof ConstantValue)
104 setValue(((ConstantValue)attrs[i]).getConstantValueIndex());
105 else
106 addAttribute(attrs[i]);
107 }
108 }
109
110 private void setValue(int index) {
111 ConstantPool cp = this.cp.getConstantPool();
112 Constant c = cp.getConstant(index);
113 value = ((ConstantObject)c).getConstantValue(cp);
114 }
115
116 /***
117 * Set (optional) initial value of field, otherwise it will be set to null/0/false
118 * by the JVM automatically.
119 */
120 public void setInitValue(String str) {
121 checkType(new ObjectType("java.lang.String"));
122
123 if(str != null)
124 value = str;
125 }
126
127 public void setInitValue(long l) {
128 checkType(Type.LONG);
129
130 if(l != 0L)
131 value = new Long(l);
132 }
133
134 public void setInitValue(int i) {
135 checkType(Type.INT);
136
137 if(i != 0)
138 value = new Integer(i);
139 }
140
141 public void setInitValue(short s) {
142 checkType(Type.SHORT);
143
144 if(s != 0)
145 value = new Integer(s);
146 }
147
148 public void setInitValue(char c) {
149 checkType(Type.CHAR);
150
151 if(c != 0)
152 value = new Integer(c);
153 }
154
155 public void setInitValue(byte b) {
156 checkType(Type.BYTE);
157
158 if(b != 0)
159 value = new Integer(b);
160 }
161
162 public void setInitValue(boolean b) {
163 checkType(Type.BOOLEAN);
164
165 if(b)
166 value = new Integer(1);
167 }
168
169 public void setInitValue(float f) {
170 checkType(Type.FLOAT);
171
172 if(f != 0.0)
173 value = new Float(f);
174 }
175
176 public void setInitValue(double d) {
177 checkType(Type.DOUBLE);
178
179 if(d != 0.0)
180 value = new Double(d);
181 }
182
183 /*** Remove any initial value.
184 */
185 public void cancelInitValue() {
186 value = null;
187 }
188
189 private void checkType(Type atype) {
190 if(type == null)
191 throw new ClassGenException("You haven't defined the type of the field yet");
192
193 if(!isFinal())
194 throw new ClassGenException("Only final fields may have an initial value!");
195
196 if(!type.equals(atype))
197 throw new ClassGenException("Types are not compatible: " + type + " vs. " + atype);
198 }
199
200 /***
201 * Get field object after having set up all necessary values.
202 */
203 public Field getField() {
204 String signature = getSignature();
205 int name_index = cp.addUtf8(name);
206 int signature_index = cp.addUtf8(signature);
207
208 if(value != null) {
209 checkType(type);
210 int index = addConstant();
211 addAttribute(new ConstantValue(cp.addUtf8("ConstantValue"),
212 2, index, cp.getConstantPool()));
213 }
214
215 return new Field(access_flags, name_index, signature_index, getAttributes(),
216 cp.getConstantPool());
217 }
218
219 private int addConstant() {
220 switch(type.getType()) {
221 case Constants.T_INT: case Constants.T_CHAR: case Constants.T_BYTE:
222 case Constants.T_BOOLEAN: case Constants.T_SHORT:
223 return cp.addInteger(((Integer)value).intValue());
224
225 case Constants.T_FLOAT:
226 return cp.addFloat(((Float)value).floatValue());
227
228 case Constants.T_DOUBLE:
229 return cp.addDouble(((Double)value).doubleValue());
230
231 case Constants.T_LONG:
232 return cp.addLong(((Long)value).longValue());
233
234 case Constants.T_REFERENCE:
235 return cp.addString(((String)value));
236
237 default:
238 throw new RuntimeException("Oops: Unhandled : " + type.getType());
239 }
240 }
241
242 public String getSignature() { return type.getSignature(); }
243
244 private ArrayList observers;
245
246 /*** Add observer for this object.
247 */
248 public void addObserver(FieldObserver o) {
249 if(observers == null)
250 observers = new ArrayList();
251
252 observers.add(o);
253 }
254
255 /*** Remove observer for this object.
256 */
257 public void removeObserver(FieldObserver o) {
258 if(observers != null)
259 observers.remove(o);
260 }
261
262 /*** Call notify() method on all observers. This method is not called
263 * automatically whenever the state has changed, but has to be
264 * called by the user after he has finished editing the object.
265 */
266 public void update() {
267 if(observers != null)
268 for(Iterator e = observers.iterator(); e.hasNext(); )
269 ((FieldObserver)e.next()).notify(this);
270 }
271
272 public String getInitValue() {
273 if(value != null) {
274 return value.toString();
275 } else
276 return null;
277 }
278
279 /***
280 * Return string representation close to declaration format,
281 * `public static final short MAX = 100', e.g..
282 *
283 * @return String representation of field
284 */
285 public final String toString() {
286 String name, signature, access; // Short cuts to constant pool
287
288 access = Utility.accessToString(access_flags);
289 access = access.equals("")? "" : (access + " ");
290 signature = type.toString();
291 name = getName();
292
293 StringBuffer buf = new StringBuffer(access + signature + " " + name);
294 String value = getInitValue();
295
296 if(value != null)
297 buf.append(" = " + value);
298
299 return buf.toString();
300 }
301
302 /*** @return deep copy of this field
303 */
304 public FieldGen copy(ConstantPoolGen cp) {
305 FieldGen fg = (FieldGen)clone();
306
307 fg.setConstantPool(cp);
308 return fg;
309 }
310 }
This page was automatically generated by Maven