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1   /*
2    * Copyright  2000-2004 The Apache Software Foundation
3    *
4    *  Licensed under the Apache License, Version 2.0 (the "License"); 
5    *  you may not use this file except in compliance with the License.
6    *  You may obtain a copy of the License at
7    *
8    *      http://www.apache.org/licenses/LICENSE-2.0
9    *
10   *  Unless required by applicable law or agreed to in writing, software
11   *  distributed under the License is distributed on an "AS IS" BASIS,
12   *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13   *  See the License for the specific language governing permissions and
14   *  limitations under the License. 
15   *
16   */ 
17  package org.apache.bcel.verifier.structurals;
18  
19  
20  import org.apache.bcel.generic.InstructionHandle;
21  
22  /***
23   * This interface defines properties of JVM bytecode subroutines.
24   * Note that it is 'abused' to maintain the top-level code in a
25   * consistent fashion, too.
26   *
27   * @version $Id: Subroutine.java 371539 2006-01-23 14:08:00Z tcurdt $
28   * @author Enver Haase
29   */
30  public interface Subroutine{
31  	/***
32  	 * Returns all the JsrInstructions that have the
33  	 * first instruction of this subroutine as their target.
34  	 * <B>Must not be invoked on the 'top-level subroutine'.</B>
35  	 */
36  	public InstructionHandle[] getEnteringJsrInstructions();
37  	
38  	/***
39  	 * Returns the one and only RET that leaves the subroutine.
40  	 * Note that JustIce has a pretty rigid notion of a subroutine.
41  	 * <B>Must not be invoked on the 'top-level subroutine'.</B>
42  	 *
43  	 * @see org.apache.bcel.verifier.structurals.Subroutines
44  	 */
45  	public InstructionHandle getLeavingRET();
46  
47  	/***
48  	 * Returns all instructions that together form this subroutine.
49  	 * Note that an instruction is part of exactly one subroutine
50  	 * (the top-level code is considered to be a special subroutine) -
51  	 * else it is not reachable at all (dead code).
52  	 */
53  	public InstructionHandle[] getInstructions();
54  
55  	/***
56  	 * Returns if the given InstructionHandle refers to an instruction
57  	 * that is part of this subroutine. This is a convenience method
58  	 * that saves iteration over the InstructionHandle objects returned
59  	 * by getInstructions().
60  	 *
61  	 * @see #getInstructions()
62  	 */
63  	public boolean contains(InstructionHandle inst);
64  
65  	/***
66  	 * Returns an int[] containing the indices of the local variable slots
67  	 * accessed by this Subroutine (read-accessed, write-accessed or both);
68  	 * local variables referenced by subroutines of this subroutine are
69  	 * not included.
70  	 *
71  	 * @see #getRecursivelyAccessedLocalsIndices()
72  	 */
73  	public int[] getAccessedLocalsIndices();
74  
75  	/***
76  	 * Returns an int[] containing the indices of the local variable slots
77  	 * accessed by this Subroutine (read-accessed, write-accessed or both);
78  	 * local variables referenced by subroutines of this subroutine are
79  	 * included.
80  	 *
81  	 * @see #getAccessedLocalsIndices()
82  	 */
83  	public int[] getRecursivelyAccessedLocalsIndices();
84  		
85  	/***
86  	 * Returns the subroutines that are directly called from this subroutine.
87  	 */
88  	public Subroutine[] subSubs();
89  }