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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 }

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