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1 /*
2  * Copyright (c) 1998, 2013, Oracle and/or its affiliates. All rights reserved.
3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4  *
5  * This code is free software; you can redistribute it and/or modify it
6  * under the terms of the GNU General Public License version 2 only, as
7  * published by the Free Software Foundation.  Oracle designates this
8  * particular file as subject to the "Classpath" exception as provided
9  * by Oracle in the LICENSE file that accompanied this code.
10  *
11  * This code is distributed in the hope that it will be useful, but WITHOUT
12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
14  * version 2 for more details (a copy is included in the LICENSE file that
15  * accompanied this code).
16  *
17  * You should have received a copy of the GNU General Public License version
18  * 2 along with this work; if not, write to the Free Software Foundation,
19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20  *
21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22  * or visit www.oracle.com if you need additional information or have any
23  * questions.
24  */
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 @jdk.Exported
46 public interface LocalVariable extends Mirror, Comparable<LocalVariable> {
47 
48     /**
49      * Gets the name of the local variable.
50      *
51      * @return a string containing the name.
52      */
name()53     String name();
54 
55     /**
56      * Returns a text representation of the type
57      * of this variable.
58      * Where the type is the type specified in the declaration
59      * of this local variable.
60      * <P>
61      * This type name is always available even if
62      * the type has not yet been created or loaded.
63      *
64      * @return a String representing the
65      * type of this local variable.
66 
67      */
typeName()68     String typeName();
69 
70     /**
71      * Returns the type of this variable.
72      * Where the type is the type specified in the declaration
73      * of this local variable.
74      * <P>
75      * Note: if the type of this variable is a reference type (class,
76      * interface, or array) and it has not been created or loaded
77      * by the class loader of the enclosing class,
78      * then ClassNotLoadedException will be thrown.
79      * Also, a reference type may have been loaded but not yet prepared,
80      * in which case the type will be returned
81      * but attempts to perform some operations on the returned type
82      * (e.g. {@link ReferenceType#fields() fields()}) will throw
83      * a {@link ClassNotPreparedException}.
84      * Use {@link ReferenceType#isPrepared()} to determine if
85      * a reference type is prepared.
86      *
87      * @see Type
88      * @see Field#type() Field.type() - for usage examples
89      * @return the {@link Type} of this local variable.
90      * @throws ClassNotLoadedException if the type has not yet been loaded
91      * through the appropriate class loader.
92      */
type()93     Type type() throws ClassNotLoadedException;
94 
95     /**
96      * Gets the JNI signature of the local variable.
97      *
98      * @see <a href="doc-files/signature.html">Type Signatures</a>
99      * @return a string containing the signature.
100      */
signature()101     String signature();
102 
103     /**
104      * Gets the generic signature for this variable if there is one.
105      * Generic signatures are described in the
106      * <cite>The Java&trade; Virtual Machine Specification</cite>.
107      *
108      * @return a string containing the generic signature, or <code>null</code>
109      * if there is no generic signature.
110      *
111      * @since 1.5
112      */
genericSignature()113     String genericSignature();
114 
115     /**
116      * Determines whether this variable can be accessed from the given
117      * {@link StackFrame}.
118      *
119      * See {@link StackFrame#visibleVariables} for a complete description
120      * variable visibility in this interface.
121      *
122      * @param frame the StackFrame querying visibility
123      * @return <code>true</code> if this variable is visible;
124      * <code>false</code> otherwise.
125      * @throws IllegalArgumentException if the stack frame's method
126      * does not match this variable's method.
127      */
isVisible(StackFrame frame)128     boolean isVisible(StackFrame frame);
129 
130     /**
131      * Determines if this variable is an argument to its method.
132      *
133      * @return <code>true</code> if this variable is an argument;
134      * <code>false</code> otherwise.
135      */
isArgument()136     boolean isArgument();
137 
138     /**
139      * Compares the specified Object with this LocalVariable for equality.
140      *
141      * @return  true if the Object is a LocalVariable, if both LocalVariables
142      * are contained in the same method (as determined by
143      * {@link Method#equals}), and if both LocalVariables mirror
144      * the same declaration within that method
145      */
equals(Object obj)146     boolean equals(Object obj);
147 
148     /**
149      * Returns the hash code value for this LocalVariable.
150      *
151      * @return the integer hash code
152      */
hashCode()153     int hashCode();
154 }
155