LocalVariableImpl


1   /*******************************************************************************
2    * Copyright (c) 2000, 2005 IBM Corporation and others.
3    * All rights reserved. This program and the accompanying materials
4    * are made available under the terms of the Eclipse Public License v1.0
5    * which accompanies this distribution, and is available at
6    * http://www.eclipse.org/legal/epl-v10.html
7    * 
8    * Contributors:
9    *     IBM Corporation - initial API and implementation
10   *******************************************************************************/
11  package org.eclipse.jdi.internal;
12  
13  
14  import com.sun.jdi.ClassNotLoadedException;
15  import com.sun.jdi.LocalVariable;
16  import com.sun.jdi.StackFrame;
17  import com.sun.jdi.Type;
18  import com.sun.jdi.VMMismatchException;
19  
20  /**
21   * this class implements the corresponding interfaces
22   * declared by the JDI specification. See the com.sun.jdi package
23   * for more information.
24   *
25   */
26  public class LocalVariableImpl extends MirrorImpl implements LocalVariable {
27      /** Method that holds local variable. */
28      private MethodImpl fMethod;
29      /** First code index at which the variable is visible (unsigned). */
30      private long fCodeIndex;
31      /** The variable's name. */
32      private String   fName;
33      /** The variable type's JNI signature. */
34      private String   fSignature;
35      /** The variable type generic signature. */
36      private String   fGenericSignature;
37      /** The variable's type */
38      private Type fType;
39      /** The variables type name */
40      private String   fTypeName;
41      /**
42       * Unsigned value used in conjunction with codeIndex.
43       * The variable can be get or set only when the current
44       * codeIndex <= current frame code index < code index + length.
45       * <p>
46       * The length is set to -1 when this variable represents an
47       * inferred argument (when local var info is unavailable).
48       * We assume that such arguments are visible for the entire
49       * method.
50       * </p>
51       * */
52      private int fLength;
53      /** The local variable's index in its frame. */
54      private int fSlot;
55      /** Is the local variable an argument of its method? */
56      private boolean fIsArgument;
57      
58      public LocalVariableImpl(VirtualMachineImpl vmImpl, MethodImpl method, long codeIndex, String   name, String   signature, String   genericSignature, int length, int slot, boolean isArgument) {
59          super("LocalVariable", vmImpl); //$NON-NLS-1$
60          fMethod = method;
61          fCodeIndex = codeIndex;
62          fName = name;
63          fSignature = signature;
64          fGenericSignature= genericSignature;
65          fLength = length;
66          fSlot = slot;
67          fIsArgument = isArgument;
68      }
69  
70      /** 
71       * @return Returns local variable's index in its frame.
72       */
73      public int slot() {
74          return fSlot;
75      }
76      
77      /** 
78       * @return Returns the hash code value.
79       */
80      public int hashCode() {
81          return fMethod.hashCode() + (int)fCodeIndex + fSlot;
82      }
83      
84      /**
85       * @return Returns true if two mirrors refer to the same entity in the target VM.
86       * @see java.lang.Object#equals(Object).
87       */
88      public boolean equals(Object   object) {
89          if (object != null && object.getClass().equals(this.getClass())) {
90              LocalVariableImpl loc = (LocalVariableImpl)object;
91              return fMethod.equals(loc.fMethod) && fCodeIndex == loc.fCodeIndex && fSlot == loc.fSlot;
92          }
93          return false;
94      }
95      
96      /**
97       * @return Returns a negative integer, zero, or a positive integer as this object is less than, equal to, or greater than the specified object.
98       */
99      public int compareTo(Object   object) {
100         if (object == null || !object.getClass().equals(this.getClass()))
101             throw new ClassCastException  (JDIMessages.LocalVariableImpl_Can__t_compare_local_variable_to_given_object_1); 
102         
103         // See if methods are the same, if not return comparison between methods.
104         LocalVariableImpl var2 = (LocalVariableImpl)object;
105         if (!method().equals(var2.method()))
106             return method().compareTo(var2.method());
107 
108         // Return comparison between the index of each local variable in its stack frame.
109         // Code indexes must be treated as unsigned. This matters if you have to compare them.
110         if (fCodeIndex < 0 || var2.fCodeIndex < 0)
111             throw new InternalError  (JDIMessages.LocalVariableImpl_Code_indexes_are_assumed_to_be_always_positive_2); 
112         
113         long index2 = var2.fCodeIndex;
114         if (fCodeIndex < index2)
115             return -1;
116         else if (fCodeIndex > index2)
117             return 1;
118         else return 0;
119     }
120     
121     /** 
122      * @return Returns true if this variable is an argument to its method.
123      */
124     public boolean isArgument() {
125         return fIsArgument;
126     }
127     
128     public boolean isVisible(StackFrame frame) throws IllegalArgumentException  , VMMismatchException {
129         checkVM(frame);
130         StackFrameImpl frameImpl = (StackFrameImpl)frame;
131         if (!fMethod.equals(frameImpl.location().method()))
132             throw new IllegalArgumentException  (JDIMessages.LocalVariableImpl_The_stack_frame__s_method_does_not_match_this_variable__s_method_3); 
133 
134         if (fLength == -1) {
135             // inferred argument - assume visible for entire method
136             return true;
137         }
138         long currentIndex = frameImpl.location().codeIndex();
139         
140         // Code indexes must be treated as unsigned. This matters if you have to compare them.
141         if (currentIndex >= 0 && fCodeIndex >= 0 && fCodeIndex + fLength >= 0)
142             return fCodeIndex <= currentIndex && currentIndex < fCodeIndex + fLength;
143 
144         throw new InternalError  (JDIMessages.LocalVariableImpl_Code_indexes_are_assumed_to_be_always_positive_4); 
145     }
146     
147     /** 
148      * @return Returns the name of the local variable.
149      */
150     public String   name() {
151         return fName;
152     }
153     
154     /** 
155      * @return Returns the signature of the local variable.
156      */
157     public String   signature() {
158         return fSignature;
159     }
160     
161     /** 
162      * @return Returns the type of the this LocalVariable. 
163      */
164     public Type type() throws ClassNotLoadedException {
165         if (fType == null) {
166             fType = TypeImpl.create(virtualMachineImpl(), fSignature, method().declaringType().classLoader());
167         }
168         return fType;
169     }
170     
171     /** 
172      * @return Returns a text representation of the declared type of this variable.
173      */
174     public String   typeName() {
175         if (fTypeName == null) {
176             fTypeName = TypeImpl.signatureToName(fSignature); 
177         }
178         return fTypeName;
179     }
180     
181     /** 
182      * @return Returns the tag of the declared type of this variable.
183      */
184     public byte tag() { 
185         return TypeImpl.signatureToTag(fSignature);
186     }
187     
188     /** 
189      * @return Returns the method that holds the local variable.
190      */
191     public MethodImpl method() { 
192         return fMethod;
193     }
194     
195     /** 
196      * @return Returns true if the local variable is the 'this' pointer.
197      */
198     public boolean isThis() {
199         return slot() == 0 && !method().isStatic();
200     }
201     
202     /**
203      * @return Returns description of Mirror object.
204      */
205     public String   toString() {
206         return fName;
207     }
208     
209     public String   genericSignature() {
210         return fGenericSignature;
211     }
212 
213 }
214
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