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25 
26 package com.sun.jdi;
27 
28 /**
29  * A local variable in the target VM. Each variable declared within a
30  * {@link Method} has its own LocalVariable object. Variables of the same
31  * name declared in different scopes have different LocalVariable objects.
32  * LocalVariables can be used alone to retrieve static information
33  * about their declaration, or can be used in conjunction with a
34  * {@link StackFrame} to set and get values.
35  *
36  * @see StackFrame
37  * @see Method
38  *
39  * @author Robert Field
40  * @author Gordon Hirsch
41  * @author James McIlree
42  * @since  1.3
43  */
44 
45 public interface LocalVariable extends Mirror, Comparable<LocalVariable> {
46 
47     /**
48      * Gets the name of the local variable.
49      *
50      * @return a string containing the name.
51      */
name()52     String name();
53 
54     /**
55      * Returns a text representation of the type
56      * of this variable.
57      * Where the type is the type specified in the declaration
58      * of this local variable.
59      * <P>
60      * This type name is always available even if
61      * the type has not yet been created or loaded.
62      *
63      * @return a String representing the
64      * type of this local variable.
65 
66      */
typeName()67     String typeName();
68 
69     /**
70      * Returns the type of this variable.
71      * Where the type is the type specified in the declaration
72      * of this local variable.
73      * <P>
74      * Note: if the type of this variable is a reference type (class,
75      * interface, or array) and it has not been created or loaded
76      * by the class loader of the enclosing class,
77      * then ClassNotLoadedException will be thrown.
78      * Also, a reference type may have been loaded but not yet prepared,
79      * in which case the type will be returned
80      * but attempts to perform some operations on the returned type
81      * (e.g. {@link ReferenceType#fields() fields()}) will throw
82      * a {@link ClassNotPreparedException}.
83      * Use {@link ReferenceType#isPrepared()} to determine if
84      * a reference type is prepared.
85      *
86      * @see Type
87      * @see Field#type() Field.type() - for usage examples
88      * @return the {@link Type} of this local variable.
89      * @throws ClassNotLoadedException if the type has not yet been loaded
90      * through the appropriate class loader.
91      */
type()92     Type type() throws ClassNotLoadedException;
93 
94     /**
95      * Gets the <a href="{@docRoot}/../specs/jni/types.html#type-signatures">
96      * type signature</a> of the local variable.
97      *
98      * @return a string containing the signature.
99      */
signature()100     String signature();
101 
102     /**
103      * Gets the generic signature for this variable if there is one.
104      * Generic signatures are described in the
105      * <cite>The Java Virtual Machine Specification</cite>.
106      *
107      * @return a string containing the generic signature, or <code>null</code>
108      * if there is no generic signature.
109      *
110      * @since 1.5
111      */
genericSignature()112     String genericSignature();
113 
114     /**
115      * Determines whether this variable can be accessed from the given
116      * {@link StackFrame}.
117      *
118      * See {@link StackFrame#visibleVariables} for a complete description
119      * variable visibility in this interface.
120      *
121      * @param frame the StackFrame querying visibility
122      * @return <code>true</code> if this variable is visible;
123      * <code>false</code> otherwise.
124      * @throws IllegalArgumentException if the stack frame's method
125      * does not match this variable's method.
126      */
isVisible(StackFrame frame)127     boolean isVisible(StackFrame frame);
128 
129     /**
130      * Determines if this variable is an argument to its method.
131      *
132      * @return <code>true</code> if this variable is an argument;
133      * <code>false</code> otherwise.
134      */
isArgument()135     boolean isArgument();
136 
137     /**
138      * Compares the specified Object with this LocalVariable for equality.
139      *
140      * @return  true if the Object is a LocalVariable, if both LocalVariables
141      * are contained in the same method (as determined by
142      * {@link Method#equals}), and if both LocalVariables mirror
143      * the same declaration within that method
144      */
equals(Object obj)145     boolean equals(Object obj);
146 
147     /**
148      * Returns the hash code value for this LocalVariable.
149      *
150      * @return the integer hash code
151      */
hashCode()152     int hashCode();
153 }
154