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1   /*
2    * Licensed to the Apache Software Foundation (ASF) under one or more
3    * contributor license agreements.  See the NOTICE file distributed with
4    * this work for additional information regarding copyright ownership.
5    * The ASF licenses this file to You under the Apache License, Version 2.0
6    * (the "License"); you may not use this file except in compliance with
7    * the License.  You may obtain a copy of the License at
8    *
9    *      http://www.apache.org/licenses/LICENSE-2.0
10   *
11   *  Unless required by applicable law or agreed to in writing, software
12   *  distributed under the License is distributed on an "AS IS" BASIS,
13   *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14   *  See the License for the specific language governing permissions and
15   *  limitations under the License.
16   *
17   */ 
18  package org.apache.bcel.verifier.statics;
19  
20  
21  import org.apache.bcel.classfile.AnnotationDefault;
22  import org.apache.bcel.classfile.AnnotationEntry;
23  import org.apache.bcel.classfile.Annotations;
24  import org.apache.bcel.classfile.BootstrapMethods;
25  import org.apache.bcel.classfile.Code;
26  import org.apache.bcel.classfile.CodeException;
27  import org.apache.bcel.classfile.ConstantClass;
28  import org.apache.bcel.classfile.ConstantDouble;
29  import org.apache.bcel.classfile.ConstantFieldref;
30  import org.apache.bcel.classfile.ConstantFloat;
31  import org.apache.bcel.classfile.ConstantInteger;
32  import org.apache.bcel.classfile.ConstantInterfaceMethodref;
33  import org.apache.bcel.classfile.ConstantInvokeDynamic;
34  import org.apache.bcel.classfile.ConstantLong;
35  import org.apache.bcel.classfile.ConstantMethodHandle;
36  import org.apache.bcel.classfile.ConstantMethodType;
37  import org.apache.bcel.classfile.ConstantMethodref;
38  import org.apache.bcel.classfile.ConstantNameAndType;
39  import org.apache.bcel.classfile.ConstantPool;
40  import org.apache.bcel.classfile.ConstantString;
41  import org.apache.bcel.classfile.ConstantUtf8;
42  import org.apache.bcel.classfile.ConstantValue;
43  import org.apache.bcel.classfile.Deprecated;
44  import org.apache.bcel.classfile.EnclosingMethod;
45  import org.apache.bcel.classfile.ExceptionTable;
46  import org.apache.bcel.classfile.Field;
47  import org.apache.bcel.classfile.InnerClass;
48  import org.apache.bcel.classfile.InnerClasses;
49  import org.apache.bcel.classfile.JavaClass;
50  import org.apache.bcel.classfile.LineNumber;
51  import org.apache.bcel.classfile.LineNumberTable;
52  import org.apache.bcel.classfile.LocalVariable;
53  import org.apache.bcel.classfile.LocalVariableTable;
54  import org.apache.bcel.classfile.LocalVariableTypeTable;
55  import org.apache.bcel.classfile.Method;
56  import org.apache.bcel.classfile.MethodParameters;
57  import org.apache.bcel.classfile.Node;
58  import org.apache.bcel.classfile.ParameterAnnotationEntry;
59  import org.apache.bcel.classfile.ParameterAnnotations;
60  import org.apache.bcel.classfile.Signature;
61  import org.apache.bcel.classfile.SourceFile;
62  import org.apache.bcel.classfile.StackMap;
63  import org.apache.bcel.classfile.StackMapEntry;
64  import org.apache.bcel.classfile.Synthetic;
65  import org.apache.bcel.classfile.Unknown;
66  import org.apache.bcel.verifier.exc.AssertionViolatedException;
67  
68  /**
69   * BCEL's Node classes (those from the classfile API that <B>accept()</B> Visitor
70   * instances) have <B>toString()</B> methods that were not designed to be robust,
71   * this gap is closed by this class.
72   * When performing class file verification, it may be useful to output which
73   * entity (e.g. a <B>Code</B> instance) is not satisfying the verifier's
74   * constraints, but in this case it could be possible for the <B>toString()</B>
75   * method to throw a RuntimeException.
76   * A (new StringRepresentation(Node n)).toString() never throws any exception.
77   * Note that this class also serves as a placeholder for more sophisticated message
78   * handling in future versions of JustIce.
79   *
80   * @version $Id: StringRepresentation.html 992795 2016-07-14 11:53:52Z britter $
81   */
82  public class StringRepresentation extends org.apache.bcel.classfile.EmptyVisitor {
83      /** The string representation, created by a visitXXX() method, output by toString(). */
84      private String tostring;
85      /** The node we ask for its string representation. Not really needed; only for debug output. */
86      private final Node n;
87  
88      /**
89       * Creates a new StringRepresentation object which is the representation of n.
90       *
91       * @see #toString()
92       */
93      public StringRepresentation(final Node n) {
94          this.n = n;
95          n.accept(this); // assign a string representation to field 'tostring' if we know n's class.
96      }
97  
98      /**
99       * Returns the String representation.
100      */
101     @Override
102     public String toString() {
103 // The run-time check below is needed because we don't want to omit inheritance
104 // of "EmptyVisitor" and provide a thousand empty methods.
105 // However, in terms of performance this would be a better idea.
106 // If some new "Node" is defined in BCEL (such as some concrete "Attribute"), we
107 // want to know that this class has also to be adapted.
108         if (tostring == null) {
109             throw new AssertionViolatedException(
110                 "Please adapt '" + getClass() + "' to deal with objects of class '" + n.getClass() + "'.");
111         }
112         return tostring;
113     }
114 
115     /**
116      * Returns the String representation of the Node object obj;
117      * this is obj.toString() if it does not throw any RuntimeException,
118      * or else it is a string derived only from obj's class name.
119      */
120     private String toString(final Node obj) {
121         String ret;
122         try {
123             ret = obj.toString();
124         }
125         
126         catch (final RuntimeException e) {
127             // including ClassFormatException, trying to convert the "signature" of a ReturnaddressType LocalVariable
128             // (shouldn't occur, but people do crazy things)
129             String s = obj.getClass().getName();
130             s = s.substring(s.lastIndexOf(".") + 1);
131             ret = "<<" + s + ">>";
132         }
133         return ret;
134     }
135 
136     ////////////////////////////////
137     // Visitor methods start here //
138     ////////////////////////////////
139     // We don't of course need to call some default implementation:
140     // e.g. we could also simply output "Code" instead of a possibly
141     // lengthy Code attribute's toString().
142     @Override
143     public void visitCode(final Code obj) {
144         //tostring = toString(obj);
145         tostring = "<CODE>"; // We don't need real code outputs.
146     }
147 
148     /**
149      * @since 6.0
150      */
151     @Override
152     public void visitAnnotation(final Annotations obj)
153     {
154         //this is invoked whenever an annotation is found
155         //when verifier is passed over a class
156         tostring = toString(obj);
157     }
158     
159     /**
160      * @since 6.0
161      */
162     @Override
163     public void visitLocalVariableTypeTable(final LocalVariableTypeTable obj)
164     {
165         //this is invoked whenever a local variable type is found
166         //when verifier is passed over a class
167         tostring = toString(obj);
168     }
169     
170     @Override
171     public void visitCodeException(final CodeException obj) {
172         tostring = toString(obj);
173     }
174 
175     @Override
176     public void visitConstantClass(final ConstantClass obj) {
177         tostring = toString(obj);
178     }
179 
180     @Override
181     public void visitConstantDouble(final ConstantDouble obj) {
182         tostring = toString(obj);
183     }
184 
185     @Override
186     public void visitConstantFieldref(final ConstantFieldref obj) {
187         tostring = toString(obj);
188     }
189 
190     @Override
191     public void visitConstantFloat(final ConstantFloat obj) {
192         tostring = toString(obj);
193     }
194 
195     @Override
196     public void visitConstantInteger(final ConstantInteger obj) {
197         tostring = toString(obj);
198     }
199 
200     @Override
201     public void visitConstantInterfaceMethodref(final ConstantInterfaceMethodref obj) {
202         tostring = toString(obj);
203     }
204 
205     @Override
206     public void visitConstantLong(final ConstantLong obj) {
207         tostring = toString(obj);
208     }
209 
210     @Override
211     public void visitConstantMethodref(final ConstantMethodref obj) {
212         tostring = toString(obj);
213     }
214 
215     @Override
216     public void visitConstantNameAndType(final ConstantNameAndType obj) {
217         tostring = toString(obj);
218     }
219 
220     @Override
221     public void visitConstantPool(final ConstantPool obj) {
222         tostring = toString(obj);
223     }
224 
225     @Override
226     public void visitConstantString(final ConstantString obj) {
227         tostring = toString(obj);
228     }
229 
230     @Override
231     public void visitConstantUtf8(final ConstantUtf8 obj) {
232         tostring = toString(obj);
233     }
234 
235     @Override
236     public void visitConstantValue(final ConstantValue obj) {
237         tostring = toString(obj);
238     }
239 
240     @Override
241     public void visitDeprecated(final Deprecated obj) {
242         tostring = toString(obj);
243     }
244 
245     @Override
246     public void visitExceptionTable(final ExceptionTable obj) {
247         tostring = toString(obj);
248     }
249 
250     @Override
251     public void visitField(final Field obj) {
252         tostring = toString(obj);
253     }
254 
255     @Override
256     public void visitInnerClass(final InnerClass obj) {
257         tostring = toString(obj);
258     }
259 
260     @Override
261     public void visitInnerClasses(final InnerClasses obj) {
262         tostring = toString(obj);
263     }
264 
265     @Override
266     public void visitJavaClass(final JavaClass obj) {
267         tostring = toString(obj);
268     }
269 
270     @Override
271     public void visitLineNumber(final LineNumber obj) {
272         tostring = toString(obj);
273     }
274 
275     @Override
276     public void visitLineNumberTable(final LineNumberTable obj) {
277         tostring = "<LineNumberTable: " + toString(obj) + ">";
278     }
279 
280     @Override
281     public void visitLocalVariable(final LocalVariable obj) {
282         tostring = toString(obj);
283     }
284 
285     @Override
286     public void visitLocalVariableTable(final LocalVariableTable obj) {
287         tostring = "<LocalVariableTable: " + toString(obj) + ">";
288     }
289 
290     @Override
291     public void visitMethod(final Method obj) {
292         tostring = toString(obj);
293     }
294 
295     @Override
296     public void visitSignature(final Signature obj) {
297         tostring = toString(obj);
298     }
299 
300     @Override
301     public void visitSourceFile(final SourceFile obj) {
302         tostring = toString(obj);
303     }
304 
305     @Override
306     public void visitStackMap(final StackMap obj) {
307         tostring = toString(obj);
308     }
309 
310     @Override
311     public void visitSynthetic(final Synthetic obj) {
312         tostring = toString(obj);
313     }
314 
315     @Override
316     public void visitUnknown(final Unknown obj) {
317         tostring = toString(obj);
318     }
319 
320     /**
321      * @since 6.0
322      */
323     @Override
324     public void visitEnclosingMethod(final EnclosingMethod obj) {
325         tostring = toString(obj);
326     }
327 
328     /**
329      * @since 6.0
330      */
331     @Override
332     public void visitBootstrapMethods(final BootstrapMethods obj) {
333         tostring = toString(obj);
334     }
335 
336     /**
337      * @since 6.0
338      */
339     @Override
340     public void visitMethodParameters(final MethodParameters obj) {
341         tostring = toString(obj);
342     }
343 
344     /**
345      * @since 6.0
346      */
347     @Override
348     public void visitConstantInvokeDynamic(final ConstantInvokeDynamic obj) {
349         tostring = toString(obj);
350     }
351 
352     /**
353      * @since 6.0
354      */
355     @Override
356     public void visitStackMapEntry(final StackMapEntry obj) {
357         tostring = toString(obj);
358     }
359     /**
360      * @since 6.0
361      */
362 
363     @Override
364     public void visitParameterAnnotation(final ParameterAnnotations obj) {
365         tostring = toString(obj);
366     }
367 
368     /**
369      * @since 6.0
370      */
371     @Override
372     public void visitAnnotationEntry(final AnnotationEntry obj) {
373         tostring = toString(obj);
374     }
375 
376     /**
377      * @since 6.0
378      */
379     @Override
380     public void visitAnnotationDefault(final AnnotationDefault obj) {
381         tostring = toString(obj);
382     }
383 
384     /**
385      * @since 6.0
386      */
387     @Override
388     public void visitConstantMethodType(final ConstantMethodType obj) {
389         tostring = toString(obj);
390     }
391 
392     /**
393      * @since 6.0
394      */
395     @Override
396     public void visitConstantMethodHandle(final ConstantMethodHandle obj) {
397         tostring = toString(obj);
398     }
399 
400     /**
401      * @since 6.0
402      */
403     @Override
404     public void visitParameterAnnotationEntry(final ParameterAnnotationEntry obj) {
405         tostring = toString(obj);
406     }
407 }