CodeVisitor


1   /***
2    * ASM: a very small and fast Java bytecode manipulation framework
3    * Copyright (C) 2000 INRIA, France Telecom
4    * Copyright (C) 2002 France Telecom
5    *
6    * This library is free software; you can redistribute it and/or
7    * modify it under the terms of the GNU Lesser General Public
8    * License as published by the Free Software Foundation; either
9    * version 2 of the License, or (at your option) any later version.
10   *
11   * This library is distributed in the hope that it will be useful,
12   * but WITHOUT ANY WARRANTY; without even the implied warranty of
13   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
14   * Lesser General Public License for more details.
15   *
16   * You should have received a copy of the GNU Lesser General Public
17   * License along with this library; if not, write to the Free Software
18   * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
19   *
20   * Contact: Eric.Bruneton@rd.francetelecom.com
21   *
22   * Author: Eric Bruneton
23   */
24  
25  package bsh.org.objectweb.asm;
26  
27  /**
28   * A visitor to visit the bytecode instructions of a Java method. The methods
29   * of this visitor must be called in the sequential order of the bytecode
30   * instructions of the visited code. The {@link #visitMaxs visitMaxs} method
31   * must be called after all the instructions have been visited. The {@link
32   * #visitTryCatchBlock visitTryCatchBlock}, {@link #visitLocalVariable
33   * visitLocalVariable} and {@link #visitLineNumber visitLineNumber} methods may
34   * be called in any order, at any time (provided the labels passed as arguments
35   * have already been visited with {@link #visitLabel visitLabel}).
36   */
37  
38  public interface CodeVisitor {
39  
40    /**
41     * Visits a zero operand instruction.
42     *
43     * @param opcode the opcode of the instruction to be visited. This opcode is
44     *      either NOP, ACONST_NULL, ICONST_M1, ICONST_0, ICONST_1, ICONST_2,
45     *      ICONST_3, ICONST_4, ICONST_5, LCONST_0, LCONST_1, FCONST_0, FCONST_1,
46     *      FCONST_2, DCONST_0, DCONST_1,
47     *
48     *      IALOAD, LALOAD, FALOAD, DALOAD, AALOAD, BALOAD, CALOAD, SALOAD,
49     *      IASTORE, LASTORE, FASTORE, DASTORE, AASTORE, BASTORE, CASTORE,
50     *      SASTORE,
51     *
52     *      POP, POP2, DUP, DUP_X1, DUP_X2, DUP2, DUP2_X1, DUP2_X2, SWAP,
53     *
54     *      IADD, LADD, FADD, DADD, ISUB, LSUB, FSUB, DSUB, IMUL, LMUL, FMUL,
55     *      DMUL, IDIV, LDIV, FDIV, DDIV, IREM, LREM, FREM, DREM, INEG, LNEG,
56     *      FNEG, DNEG, ISHL, LSHL, ISHR, LSHR, IUSHR, LUSHR, IAND, LAND, IOR,
57     *      LOR, IXOR, LXOR,
58     *
59     *      I2L, I2F, I2D, L2I, L2F, L2D, F2I, F2L, F2D, D2I, D2L, D2F, I2B, I2C,
60     *      I2S,
61     *
62     *      LCMP, FCMPL, FCMPG, DCMPL, DCMPG,
63     *
64     *      IRETURN, LRETURN, FRETURN, DRETURN, ARETURN, RETURN,
65     *
66     *      ARRAYLENGTH,
67     *
68     *      ATHROW,
69     *
70     *      MONITORENTER, or MONITOREXIT.
71     */
72  
73    void visitInsn (int opcode);
74  
75    /**
76     * Visits an instruction with a single int operand.
77     *
78     * @param opcode the opcode of the instruction to be visited. This opcode is
79     *      either BIPUSH, SIPUSH or NEWARRAY.
80     * @param operand the operand of the instruction to be visited.
81     */
82  
83    void visitIntInsn (int opcode, int operand);
84  
85    /**
86     * Visits a local variable instruction. A local variable instruction is an
87     * instruction that loads or stores the value of a local variable.
88     *
89     * @param opcode the opcode of the local variable instruction to be visited.
90     *      This opcode is either ILOAD, LLOAD, FLOAD, DLOAD, ALOAD, ISTORE,
91     *      LSTORE, FSTORE, DSTORE, ASTORE or RET.
92     * @param var the operand of the instruction to be visited. This operand is
93     *      the index of a local variable.
94     */
95  
96    void visitVarInsn (int opcode, int var);
97  
98    /**
99     * Visits a type instruction. A type instruction is an instruction that
100    * takes a type descriptor as parameter.
101    *
102    * @param opcode the opcode of the type instruction to be visited. This opcode
103    *      is either NEW, ANEWARRAY, CHECKCAST or INSTANCEOF.
104    * @param desc the operand of the instruction to be visited. This operand is
105    *      must be a fully qualified class name in internal form, or the type
106    *      descriptor of an array type (see {@link Type Type}).
107    */
108 
109   void visitTypeInsn (int opcode, String   desc);
110 
111   /**
112    * Visits a field instruction. A field instruction is an instruction that
113    * loads or stores the value of a field of an object.
114    *
115    * @param opcode the opcode of the type instruction to be visited. This opcode
116    *      is either GETSTATIC, PUTSTATIC, GETFIELD or PUTFIELD.
117    * @param owner the internal name of the field's owner class (see {@link
118    *      Type#getInternalName getInternalName}).
119    * @param name the field's name.
120    * @param desc the field's descriptor (see {@link Type Type}).
121    */
122 
123   void visitFieldInsn (int opcode, String   owner, String   name, String   desc);
124 
125   /**
126    * Visits a method instruction. A method instruction is an instruction that
127    * invokes a method.
128    *
129    * @param opcode the opcode of the type instruction to be visited. This opcode
130    *      is either INVOKEVIRTUAL, INVOKESPECIAL, INVOKESTATIC or
131    *      INVOKEINTERFACE.
132    * @param owner the internal name of the method's owner class (see {@link
133    *      Type#getInternalName getInternalName}).
134    * @param name the method's name.
135    * @param desc the method's descriptor (see {@link Type Type}).
136    */
137 
138   void visitMethodInsn (int opcode, String   owner, String   name, String   desc);
139 
140   /**
141    * Visits a jump instruction. A jump instruction is an instruction that may
142    * jump to another instruction.
143    *
144    * @param opcode the opcode of the type instruction to be visited. This opcode
145    *      is either IFEQ, IFNE, IFLT, IFGE, IFGT, IFLE, IF_ICMPEQ, IF_ICMPNE,
146    *      IF_ICMPLT, IF_ICMPGE, IF_ICMPGT, IF_ICMPLE, IF_ACMPEQ, IF_ACMPNE,
147    *      GOTO, JSR, IFNULL or IFNONNULL.
148    * @param label the operand of the instruction to be visited. This operand is
149    *      a label that designates the instruction to which the jump instruction
150    *      may jump.
151    */
152 
153   void visitJumpInsn (int opcode, Label label);
154 
155   /**
156    * Visits a label. A label designates the instruction that will be visited
157    * just after it.
158    *
159    * @param label a {@link Label Label} object.
160    */
161 
162   void visitLabel (Label label);
163 
164   // -------------------------------------------------------------------------
165   // Special instructions
166   // -------------------------------------------------------------------------
167 
168   /**
169    * Visits a LDC instruction.
170    *
171    * @param cst the constant to be loaded on the stack. This parameter must be
172    *      a non null {@link java.lang.Integer Integer}, a {@link java.lang.Float
173    *      Float}, a {@link java.lang.Long Long}, a {@link java.lang.Double
174    *      Double} or a {@link String String}.
175    */
176 
177   void visitLdcInsn (Object   cst);
178 
179   /**
180    * Visits an IINC instruction.
181    *
182    * @param var index of the local variable to be incremented.
183    * @param increment amount to increment the local variable by.
184    */
185 
186   void visitIincInsn (int var, int increment);
187 
188   /**
189    * Visits a TABLESWITCH instruction.
190    *
191    * @param min the minimum key value.
192    * @param max the maximum key value.
193    * @param dflt beginning of the default handler block.
194    * @param labels beginnings of the handler blocks. <tt>labels[i]</tt> is the
195    *      beginning of the handler block for the <tt>min + i</tt> key.
196    */
197 
198   void visitTableSwitchInsn (int min, int max, Label dflt, Label labels[]);
199 
200   /**
201    * Visits a LOOKUPSWITCH instruction.
202    *
203    * @param dflt beginning of the default handler block.
204    * @param keys the values of the keys.
205    * @param labels beginnings of the handler blocks. <tt>labels[i]</tt> is the
206    *      beginning of the handler block for the <tt>keys[i]</tt> key.
207    */
208 
209   void visitLookupSwitchInsn (Label dflt, int keys[], Label labels[]);
210 
211   /**
212    * Visits a MULTIANEWARRAY instruction.
213    *
214    * @param desc an array type descriptor (see {@link Type Type}).
215    * @param dims number of dimensions of the array to allocate.
216    */
217 
218   void visitMultiANewArrayInsn (String   desc, int dims);
219 
220   // -------------------------------------------------------------------------
221   // Exceptions table entries, max stack size and max locals
222   // -------------------------------------------------------------------------
223 
224   /**
225    * Visits a try catch block.
226    *
227    * @param start beginning of the exception handler's scope (inclusive).
228    * @param end end of the exception handler's scope (exclusive).
229    * @param handler beginning of the exception handler's code.
230    * @param type internal name of the type of exceptions handled by the handler,
231    *      or <tt>null</tt> to catch any exceptions (for "finally" blocks).
232    * @throws IllegalArgumentException if one of the labels has not already been
233    *      visited by this visitor (by the {@link #visitLabel visitLabel}
234    *      method).
235    */
236 
237   void visitTryCatchBlock (Label start, Label end, Label handler, String   type);
238 
239   /**
240    * Visits the maximum stack size and the maximum number of local variables of
241    * the method.
242    *
243    * @param maxStack maximum stack size of the method.
244    * @param maxLocals maximum number of local variables for the method.
245    */
246 
247   void visitMaxs (int maxStack, int maxLocals);
248 
249   // -------------------------------------------------------------------------
250   // Debug information
251   // -------------------------------------------------------------------------
252 
253   /**
254    * Visits a local variable declaration.
255    *
256    * @param name the name of a local variable.
257    * @param desc the type descriptor of this local variable.
258    * @param start the first instruction corresponding to the scope of this
259    *      local variable (inclusive).
260    * @param end the last instruction corresponding to the scope of this
261    *      local variable (exclusive).
262    * @param index the local variable's index.
263    * @throws IllegalArgumentException if one of the labels has not already been
264    *      visited by this visitor (by the {@link #visitLabel visitLabel}
265    *      method).
266    */
267 
268   void visitLocalVariable (
269     String   name,
270     String   desc,
271     Label start,
272     Label end,
273     int index);
274 
275   /**
276    * Visits a line number declaration.
277    *
278    * @param line a line number. This number refers to the source file
279    *      from which the class was compiled.
280    * @param start the first instruction corresponding to this line number.
281    * @throws IllegalArgumentException if <tt>start</tt> has not already been
282    *      visited by this visitor (by the {@link #visitLabel visitLabel}
283    *      method).
284    */
285 
286   void visitLineNumber (int line, Label start);
287 }
288
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