ClassGen


1   package com.sun.org.apache.bcel.internal.generic;
2   
3   /* ====================================================================
4    * The Apache Software License, Version 1.1
5    *
6    * Copyright (c) 2001 The Apache Software Foundation.  All rights
7    * reserved.
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10   * modification, are permitted provided that the following conditions
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14   *    notice, this list of conditions and the following disclaimer.
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21   * 3. The end-user documentation included with the redistribution,
22   *    if any, must include the following acknowledgment:
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26   *    if and wherever such third-party acknowledgments normally appear.
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51   * This software consists of voluntary contributions made by many
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54   * <http://www.apache.org/>.
55   */
56  
57  import com.sun.org.apache.bcel.internal.Constants;
58  import com.sun.org.apache.bcel.internal.classfile.*;
59  import java.util.ArrayList  ;
60  import java.util.Iterator  ;
61  
62  /** 
63   * Template class for building up a java class. May be initialized with an
64   * existing java class (file).
65   *
66   * @see JavaClass
67   * @version $Id: ClassGen.java,v 1.1.1.1 2001/10/29 20:00:07 jvanzyl Exp $
68   * @author  <A HREF="mailto:markus.dahm@berlin.de">M. Dahm</A>
69   */
70  public class ClassGen extends AccessFlags implements Cloneable   {
71    /* Corresponds to the fields found in a JavaClass object.
72     */
73    private String     class_name, super_class_name, file_name;
74    private int      class_name_index = -1, superclass_name_index = -1;
75    private int      major = Constants.MAJOR_1_1, minor = Constants.MINOR_1_1;
76  
77    private ConstantPoolGen cp; // Template for building up constant pool
78  
79    // ArrayLists instead of arrays to gather fields, methods, etc.
80    private ArrayList     field_vec     = new ArrayList  ();
81    private ArrayList     method_vec    = new ArrayList  ();
82    private ArrayList     attribute_vec = new ArrayList  ();
83    private ArrayList     interface_vec = new ArrayList  ();
84  
85    /** Convenience constructor to set up some important values initially.
86     *
87     * @param class_name fully qualified class name
88     * @param super_class_name fully qualified superclass name
89     * @param file_name source file name
90     * @param access_flags access qualifiers
91     * @param interfaces implemented interfaces
92     */
93    public ClassGen(String   class_name, String   super_class_name, String   file_name,
94            int access_flags, String  [] interfaces) {
95      this.class_name       = class_name;
96      this.super_class_name = super_class_name;
97      this.file_name        = file_name;
98      this.access_flags     = access_flags;
99      cp = new ConstantPoolGen(); // Create empty constant pool
100 
101     // Put everything needed by default into the constant pool and the vectors
102     addAttribute(new SourceFile(cp.addUtf8("SourceFile"), 2,
103                 cp.addUtf8(file_name), cp.getConstantPool()));
104     class_name_index      = cp.addClass(class_name);
105     superclass_name_index = cp.addClass(super_class_name);
106 
107     if(interfaces != null)
108       for(int i=0; i < interfaces.length; i++)
109     addInterface(interfaces[i]);
110   }
111 
112   /**
113    * Initialize with existing class.
114    * @param clazz JavaClass object (e.g. read from file)
115    */
116   public ClassGen(JavaClass clazz) {
117     class_name_index      = clazz.getClassNameIndex();
118     superclass_name_index = clazz.getSuperclassNameIndex();
119     class_name            = clazz.getClassName();
120     super_class_name      = clazz.getSuperclassName();
121     file_name             = clazz.getSourceFileName();
122     access_flags          = clazz.getAccessFlags();
123     cp                    = new ConstantPoolGen(clazz.getConstantPool());
124     major                 = clazz.getMajor();
125     minor                 = clazz.getMinor();
126 
127     Attribute[] attributes = clazz.getAttributes();
128     Method[]    methods    = clazz.getMethods();
129     Field[]     fields     = clazz.getFields();
130     String  []    interfaces = clazz.getInterfaceNames();
131     
132     for(int i=0; i < interfaces.length; i++)
133       addInterface(interfaces[i]);
134 
135     for(int i=0; i < attributes.length; i++)
136       addAttribute(attributes[i]);
137 
138     for(int i=0; i < methods.length; i++)
139       addMethod(methods[i]);
140 
141     for(int i=0; i < fields.length; i++)
142       addField(fields[i]);
143   }
144 
145   /**
146    * @return the (finally) built up Java class object.
147    */
148   public JavaClass getJavaClass() {
149     int[]        interfaces = getInterfaces();
150     Field[]      fields     = getFields();
151     Method[]     methods    = getMethods();
152     Attribute[]  attributes = getAttributes();
153 
154     // Must be last since the above calls may still add something to it
155     ConstantPool cp         = this.cp.getFinalConstantPool();
156     
157     return new JavaClass(class_name_index, superclass_name_index,
158              file_name, major, minor, access_flags,
159              cp, interfaces, fields, methods, attributes);
160   }
161 
162   /**
163    * Add an interface to this class, i.e., this class has to implement it.
164    * @param name interface to implement (fully qualified class name)
165    */
166   public void addInterface(String   name) {
167     interface_vec.add(name);
168   }
169 
170   /**
171    * Remove an interface from this class.
172    * @param name interface to remove (fully qualified name)
173    */
174   public void removeInterface(String   name) {
175     interface_vec.remove(name);
176   }
177 
178   /**
179    * @return major version number of class file
180    */
181   public int  getMajor()      { return major; }
182 
183   /** Set major version number of class file, default value is 45 (JDK 1.1)
184    * @param major major version number
185    */
186   public void setMajor(int major) {
187     this.major = major;
188   }    
189 
190   /** Set minor version number of class file, default value is 3 (JDK 1.1)
191    * @param minor minor version number
192    */
193   public void setMinor(int minor) {
194     this.minor = minor;
195   }    
196 
197   /**
198    * @return minor version number of class file
199    */
200   public int  getMinor()      { return minor; }
201 
202   /**
203    * Add an attribute to this class.
204    * @param a attribute to add
205    */
206   public void addAttribute(Attribute a)    { attribute_vec.add(a); }
207 
208   /**
209    * Add a method to this class.
210    * @param m method to add
211    */
212   public void addMethod(Method m)          { method_vec.add(m); }
213 
214   /**
215    * Convenience method.
216    *
217    * Add an empty constructor to this class that does nothing but calling super().
218    * @param access rights for constructor
219    */
220   public void addEmptyConstructor(int access_flags) {
221     InstructionList il = new InstructionList();
222     il.append(InstructionConstants.THIS); // Push `this'
223     il.append(new INVOKESPECIAL(cp.addMethodref(super_class_name,
224                         "<init>", "()V")));
225     il.append(InstructionConstants.RETURN);
226 
227     MethodGen mg = new MethodGen(access_flags, Type.VOID, Type.NO_ARGS, null,
228                "<init>", class_name, il, cp);
229     mg.setMaxStack(1);
230     addMethod(mg.getMethod());
231   }
232 
233   /**
234    * Add a field to this class.
235    * @param f field to add
236    */
237   public void addField(Field f)            { field_vec.add(f); }
238 
239   public boolean containsField(Field f)    { return field_vec.contains(f); }
240   
241   /** @return field object with given name, or null
242    */
243   public Field containsField(String   name) {
244     for(Iterator   e=field_vec.iterator(); e.hasNext(); ) {
245       Field f = (Field)e.next();
246       if(f.getName().equals(name))
247     return f;
248     }
249 
250     return null;
251   }
252 
253   /** @return method object with given name and signature, or null
254    */
255   public Method containsMethod(String   name, String   signature) {
256     for(Iterator   e=method_vec.iterator(); e.hasNext();) {
257       Method m = (Method)e.next();
258       if(m.getName().equals(name) && m.getSignature().equals(signature))
259     return m;
260     }
261 
262     return null;
263   }
264 
265   /**
266    * Remove an attribute from this class.
267    * @param a attribute to remove
268    */
269   public void removeAttribute(Attribute a) { attribute_vec.remove(a); }
270 
271   /**
272    * Remove a method from this class.
273    * @param m method to remove
274    */
275   public void removeMethod(Method m)       { method_vec.remove(m); }
276 
277   /** Replace given method with new one. If the old one does not exist
278    * add the new_ method to the class anyway.
279    */
280   public void replaceMethod(Method old, Method new_) {
281     if(new_ == null)
282       throw new ClassGenException("Replacement method must not be null");
283 
284     int i = method_vec.indexOf(old);
285 
286     if(i < 0)
287       method_vec.add(new_);
288     else
289       method_vec.set(i, new_);
290   }
291 
292   /** Replace given field with new one. If the old one does not exist
293    * add the new_ field to the class anyway.
294    */
295   public void replaceField(Field old, Field new_) {
296     if(new_ == null)
297       throw new ClassGenException("Replacement method must not be null");
298 
299     int i = field_vec.indexOf(old);
300 
301     if(i < 0)
302       field_vec.add(new_);
303     else
304       field_vec.set(i, new_);
305   }
306 
307   /**
308    * Remove a field to this class.
309    * @param f field to remove
310    */
311   public void removeField(Field f)         { field_vec.remove(f); }
312 
313   public String   getClassName()      { return class_name; }
314   public String   getSuperclassName() { return super_class_name; }
315   public String   getFileName()       { return file_name; }
316 
317   public void setClassName(String   name) {
318     class_name = name.replace('/', '.');
319     class_name_index = cp.addClass(name);
320   }
321 
322   public void setSuperclassName(String   name) {
323     super_class_name = name.replace('/', '.');
324     superclass_name_index = cp.addClass(name);
325   }
326 
327   public Method[] getMethods() {
328     Method[] methods = new Method[method_vec.size()];
329     method_vec.toArray(methods);
330     return methods;
331   }
332 
333   public void setMethods(Method[] methods) {
334     method_vec.clear();
335     for(int m=0; m<methods.length; m++)
336       addMethod(methods[m]);
337   }
338 
339   public void setMethodAt(Method method, int pos) {
340     method_vec.set(pos, method);
341   }
342 
343   public Method getMethodAt(int pos) {
344     return (Method)method_vec.get(pos);
345   }
346 
347   public String  [] getInterfaceNames() {
348     int      size = interface_vec.size();
349     String  [] interfaces = new String  [size];
350 
351     interface_vec.toArray(interfaces);
352     return interfaces;
353   }
354 
355   public int[] getInterfaces() {
356     int   size = interface_vec.size();
357     int[] interfaces = new int[size];
358 
359     for(int i=0; i < size; i++)
360       interfaces[i] = cp.addClass((String  )interface_vec.get(i));
361 
362     return interfaces;
363   }
364 
365   public Field[] getFields() {
366     Field[] fields = new Field[field_vec.size()];
367     field_vec.toArray(fields);
368     return fields;
369   }
370 
371   public Attribute[] getAttributes() {
372     Attribute[] attributes = new Attribute[attribute_vec.size()];
373     attribute_vec.toArray(attributes);
374     return attributes;
375   }
376 
377   public ConstantPoolGen getConstantPool() { return cp; }
378   public void setConstantPool(ConstantPoolGen constant_pool) {
379     cp = constant_pool;
380   }    
381 
382   public void setClassNameIndex(int class_name_index) {
383     this.class_name_index = class_name_index;
384     class_name = cp.getConstantPool().
385       getConstantString(class_name_index, Constants.CONSTANT_Class).replace('/', '.');
386   }
387 
388   public void setSuperclassNameIndex(int superclass_name_index) {
389     this.superclass_name_index = superclass_name_index;
390     super_class_name = cp.getConstantPool().
391       getConstantString(superclass_name_index, Constants.CONSTANT_Class).replace('/', '.');
392   }
393 
394   public int getSuperclassNameIndex() { return superclass_name_index; }    
395 
396   public int getClassNameIndex()   { return class_name_index; }
397 
398   private ArrayList   observers;
399 
400   /** Add observer for this object.
401    */
402   public void addObserver(ClassObserver o) {
403     if(observers == null)
404       observers = new ArrayList  ();
405 
406     observers.add(o);
407   }
408 
409   /** Remove observer for this object.
410    */
411   public void removeObserver(ClassObserver o) {
412     if(observers != null)
413       observers.remove(o);
414   }
415 
416   /** Call notify() method on all observers. This method is not called
417    * automatically whenever the state has changed, but has to be
418    * called by the user after he has finished editing the object.
419    */
420   public void update() {
421     if(observers != null)
422       for(Iterator   e = observers.iterator(); e.hasNext(); )
423     ((ClassObserver)e.next()).notify(this);
424   }
425 
426   public Object   clone() {
427     try {
428       return super.clone();
429     } catch(CloneNotSupportedException   e) {
430       System.err.println(e);
431       return null;
432     }
433   }
434 }
435
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