1 /*
2 * Copyright (c) 1998, 2017, 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 point within the executing code of the target VM.
30 * Locations are used to identify the current position of
31 * a suspended thread (analogous to an instruction pointer or
32 * program counter register in native programs). They are also used
33 * to identify the position at which to set a breakpoint.
34 * <p>
35 * The availability of a line number for a location will
36 * depend on the level of debugging information available from the
37 * target VM.
38 * <p>
39 * Several mirror interfaces have locations. Each such mirror
40 * extends a {@link Locatable} interface.
41 * <p>
42 * <a id="strata"><b>Strata</b></a>
43 * <p>
44 * The source information for a Location is dependent on the
45 * <i>stratum</i> which is used. A stratum is a source code
46 * level within a sequence of translations. For example,
47 * say the baz program is written in the programming language
48 * "Foo" then translated to the language "Bar" and finally
49 * translated into the Java programming language. The
50 * Java programming language stratum is named
51 * <code>"Java"</code>, let's say the other strata are named
52 * "Foo" and "Bar". A given location (as viewed by the
53 * {@link #sourceName()} and {@link #lineNumber()} methods)
54 * might be at line 14 of "baz.foo" in the <code>"Foo"</code>
55 * stratum, line 23 of "baz.bar" in the <code>"Bar"</code>
56 * stratum and line 71 of the <code>"Java"</code> stratum.
57 * Note that while the Java programming language may have
58 * only one source file for a reference type, this restriction
59 * does not apply to other strata - thus each Location should
60 * be consulted to determine its source path.
61 * Queries which do not specify a stratum
62 * ({@link #sourceName()}, {@link #sourcePath()} and
63 * {@link #lineNumber()}) use the VM's default stratum
64 * ({@link VirtualMachine#getDefaultStratum()}).
65 * If the specified stratum (whether explicitly specified
66 * by a method parameter or implicitly as the VM's default)
67 * is <code>null</code> or is not available in the declaring
68 * type, the declaring type's default stratum is used
69 * ({@link #declaringType()}.{@link ReferenceType#defaultStratum()
70 * defaultStratum()}). Note that in the normal case, of code
71 * that originates as Java programming language source, there
72 * will be only one stratum (<code>"Java"</code>) and it will be
73 * returned as the default. To determine the available strata
74 * use {@link ReferenceType#availableStrata()}.
75 *
76 * @see com.sun.jdi.request.EventRequestManager
77 * @see StackFrame
78 * @see com.sun.jdi.event.BreakpointEvent
79 * @see com.sun.jdi.event.ExceptionEvent
80 * @see Locatable
81 *
82 * @author Robert Field
83 * @author Gordon Hirsch
84 * @author James McIlree
85 * @since 1.3
86 */
87 public interface Location extends Mirror, Comparable<Location> {
88
89 /**
90 * Gets the type to which this Location belongs. Normally
91 * the declaring type is a {@link ClassType}, but executable
92 * locations also may exist within the static initializer of an
93 * {@link InterfaceType}.
94 *
95 * @return the {@link ReferenceType} containing this Location.
96 */
97 ReferenceType declaringType();
98
99 /**
100 * Gets the method containing this Location.
101 *
102 * @return the location's {@link Method}.
103 */
104 Method method();
105
106 /**
107 * Gets the code position within this location's method.
108 *
109 * @return the long representing the position within the method
110 * or -1 if location is within a native method.
111 */
112 long codeIndex();
113
114 /**
115 * Gets an identifing name for the source corresponding to
116 * this location.
117 * <P>
118 * This method is equivalent to
119 * <code>sourceName(vm.getDefaultStratum())</code> -
120 * see {@link #sourceName(String)}
121 * for more information.
122 *
123 * @return a string specifying the source
124 * @throws AbsentInformationException if the source name is not
125 * known
126 */
127 String sourceName() throws AbsentInformationException;
128
129 /**
130 * Gets an identifing name for the source corresponding to
131 * this location. Interpretation of this string is the
132 * responsibility of the source repository mechanism.
133 * <P>
134 * Returned name is for the specified <i>stratum</i>
135 * (see the {@link Location class comment} for a
136 * description of strata).
137 * <P>
138 * The returned string is the unqualified name of the source
139 * file for this Location. For example,
140 * <CODE>java.lang.Thread</CODE> would return
141 * <CODE>"Thread.java"</CODE>.
142 *
143 * @param stratum The stratum to retrieve information from
144 * or <code>null</code> for the declaring type's
145 * default stratum.
146 *
147 * @return a string specifying the source
148 *
149 * @throws AbsentInformationException if the source name is not
150 * known
151 *
152 * @since 1.4
153 */
154 String sourceName(String stratum) throws AbsentInformationException;
155
156 /**
157 * Gets the path to the source corresponding to this
158 * location.
159 * <P>
160 * This method is equivalent to
161 * <code>sourcePath(vm.getDefaultStratum())</code> -
162 * see {@link #sourcePath(String)}
163 * for more information.
164 *
165 * @return a string specifying the source
166 *
167 * @throws AbsentInformationException if the source name is not
168 * known
169 */
170 String sourcePath() throws AbsentInformationException;
171
172 /**
173 * Gets the path to the source corresponding to this
174 * location. Interpretation of this string is the
175 * responsibility of the source repository mechanism.
176 * <P>
177 * Returned path is for the specified <i>stratum</i>
178 * (see the {@link Location class comment} for a
179 * description of strata).
180 * <P>
181 * In the reference implementation, for strata which
182 * do not explicitly specify source path (the Java
183 * programming language stratum never does), the returned
184 * string is the package name of {@link #declaringType()}
185 * converted to a platform dependent path followed by the
186 * unqualified name of the source file for this Location
187 * ({@link #sourceName sourceName(stratum)}).
188 * For example, on a
189 * Windows platform, <CODE>java.lang.Thread</CODE>
190 * would return
191 * <CODE>"java\lang\Thread.java"</CODE>.
192 *
193 * @param stratum The stratum to retrieve information from
194 * or <code>null</code> for the declaring type's
195 * default stratum.
196 *
197 * @return a string specifying the source
198 *
199 * @throws AbsentInformationException if the source name is not
200 * known
201 *
202 * @since 1.4
203 */
204 String sourcePath(String stratum) throws AbsentInformationException;
205
206 /**
207 * Gets the line number of this Location.
208 * <P>
209 * This method is equivalent to
210 * <code>lineNumber(vm.getDefaultStratum())</code> -
211 * see {@link #lineNumber(String)}
212 * for more information.
213 *
214 * @return an int specifying the line in the source, returns
215 * -1 if the information is not available; specifically, always
216 * returns -1 for native methods.
217 */
218 int lineNumber();
219
220 /**
221 * The line number of this Location. The line number is
222 * relative to the source specified by
223 * {@link #sourceName(String) sourceName(stratum)}.
224 * <P>
225 * Returned line number is for the specified <i>stratum</i>
226 * (see the {@link Location class comment} for a
227 * description of strata).
228 *
229 * @param stratum The stratum to retrieve information from
230 * or <code>null</code> for the declaring type's
231 * default stratum.
232 *
233 * @return an int specifying the line in the source, returns
234 * -1 if the information is not available; specifically, always
235 * returns -1 for native methods.
236 *
237 * @since 1.4
238 */
239 int lineNumber(String stratum);
240
241 /**
242 * Compares the specified Object with this Location for equality.
243 *
244 * @return true if the Object is a Location and if it refers to
245 * the same point in the same VM as this Location.
246 */
247 boolean equals(Object obj);
248
249 /**
250 * Returns the hash code value for this Location.
251 *
252 * @return the integer hash code
253 */
254 int hashCode();
255 }