/* * Copyright (c) 1998, 2004, Oracle and/or its affiliates. All rights reserved. * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. * * This code is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License version 2 only, as * published by the Free Software Foundation.  Oracle designates this * particular file as subject to the "Classpath" exception as provided * by Oracle in the LICENSE file that accompanied this code. * * This code is distributed in the hope that it will be useful, but WITHOUT * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License * version 2 for more details (a copy is included in the LICENSE file that * accompanied this code). * * You should have received a copy of the GNU General Public License version * 2 along with this work; if not, write to the Free Software Foundation, * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. * * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA * or visit www.oracle.com if you need additional information or have any * questions. */ package com.sun.jdi; import java.util.List; /** * A point within the executing code of the target VM. * Locations are used to identify the current position of * a suspended thread (analogous to an instruction pointer or * program counter register in native programs). They are also used * to identify the position at which to set a breakpoint. * <p> * The availability of a line number for a location will * depend on the level of debugging information available from the * target VM. * <p> * Several mirror interfaces have locations. Each such mirror * extends a {@link Locatable} interface. * <p> * <a name="strata"><b>Strata</b></a> * <p> * The source information for a Location is dependent on the * <i>stratum</i> which is used. A stratum is a source code * level within a sequence of translations.  For example, * say the baz program is written in the programming language * "Foo" then translated to the language "Bar" and finally * translated into the Java programming language.  The * Java programming language stratum is named * <code>"Java"</code>, let's say the other strata are named * "Foo" and "Bar".  A given location (as viewed by the * {@link #sourceName()} and {@link #lineNumber()} methods) * might be at line 14 of "baz.foo" in the <code>"Foo"</code> * stratum, line 23 of "baz.bar" in the <code>"Bar"</code> * stratum and line 71 of the <code>"Java"</code> stratum. * Note that while the Java programming language may have * only one source file for a reference type, this restriction * does not apply to other strata - thus each Location should * be consulted to determine its source path. * Queries which do not specify a stratum * ({@link #sourceName()}, {@link #sourcePath()} and * {@link #lineNumber()}) use the VM's default stratum * ({@link VirtualMachine#getDefaultStratum()}). * If the specified stratum (whether explicitly specified * by a method parameter or implicitly as the VM's default) * is <code>null</code> or is not available in the declaring * type, the declaring type's default stratum is used * ({@link #declaringType()}.{@link ReferenceType#defaultStratum() * defaultStratum()}).  Note that in the normal case, of code * that originates as Java programming language source, there * will be only one stratum (<code>"Java"</code>) and it will be * returned as the default.  To determine the available strata * use {@link ReferenceType#availableStrata()}. * * @see com.sun.jdi.request.EventRequestManager * @see StackFrame * @see com.sun.jdi.event.BreakpointEvent * @see com.sun.jdi.event.ExceptionEvent * @see Locatable * * @author Robert Field * @author Gordon Hirsch * @author James McIlree * @since 1.3 */public interface Location extends Mirror, Comparable<Location> {     /**     * Gets the type to which this Location belongs. Normally     * the declaring type is a {@link ClassType}, but executable     * locations also may exist within the static initializer of an     * {@link InterfaceType}.     *     * @return the {@link ReferenceType} containing this Location.     */    ReferenceType declaringType();     /**     * Gets the method containing this Location.     *     * @return the location's {@link Method}.     */    Method method();     /**     * Gets the code position within this location's method.     *     * @return the long representing the position within the method     * or -1 if location is within a native method.     */    long codeIndex();     /**     * Gets an identifing name for the source corresponding to     * this location.     * <P>     * This method is equivalent to     * <code>sourceName(vm.getDefaultStratum())</code> -     * see {@link #sourceName(String)}     * for more information.     *     * @return a string specifying the source     * @throws AbsentInformationException if the source name is not     * known     */    String sourceName() throws AbsentInformationException;      /**     * Gets an identifing name for the source corresponding to     * this location. Interpretation of this string is the     * responsibility of the source repository mechanism.     * <P>     * Returned name is for the specified <i>stratum</i>     * (see the {@link Location class comment} for a     * description of strata).     * <P>     * The returned string is the unqualified name of the source     * file for this Location.  For example,     * <CODE>java.lang.Thread</CODE> would return     * <CODE>"Thread.java"</CODE>.     *     * @param stratum The stratum to retrieve information from     * or <code>null</code> for the declaring type's     * default stratum.     *     * @return a string specifying the source     *     * @throws AbsentInformationException if the source name is not     * known     *     * @since 1.4     */    String sourceName(String stratum)                        throws AbsentInformationException;     /**     * Gets the path to the source corresponding to this     * location.     * <P>     * This method is equivalent to     * <code>sourcePath(vm.getDefaultStratum())</code> -     * see {@link #sourcePath(String)}     * for more information.     *     * @return a string specifying the source     *     * @throws AbsentInformationException if the source name is not     * known     */    String sourcePath() throws AbsentInformationException;      /**     * Gets the path to the source corresponding to this     * location. Interpretation of this string is the     * responsibility of the source repository mechanism.     * <P>     * Returned path is for the specified <i>stratum</i>     * (see the {@link Location class comment} for a     * description of strata).     * <P>     * In the reference implementation, for strata which     * do not explicitly specify source path (the Java     * programming language stratum never does), the returned     * string is the package name of {@link #declaringType()}     * converted to a platform dependent path followed by the     * unqualified name of the source file for this Location     * ({@link #sourceName sourceName(stratum)}).     * For example, on a     * Windows platform, <CODE>java.lang.Thread</CODE>     * would return     * <CODE>"java\lang\Thread.java"</CODE>.     *     * @param stratum The stratum to retrieve information from     * or <code>null</code> for the declaring type's     * default stratum.     *     * @return a string specifying the source     *     * @throws AbsentInformationException if the source name is not     * known     *     * @since 1.4     */    String sourcePath(String stratum)                         throws AbsentInformationException;     /**     * Gets the line number of this Location.     * <P>     * This method is equivalent to     * <code>lineNumber(vm.getDefaultStratum())</code> -     * see {@link #lineNumber(String)}     * for more information.     *     * @return an int specifying the line in the source, returns     * -1 if the information is not available; specifically, always     * returns -1 for native methods.     */    int lineNumber();     /**     * The line number of this Location.  The line number is     * relative to the source specified by     * {@link #sourceName(String) sourceName(stratum)}.     * <P>     * Returned line number is for the specified <i>stratum</i>     * (see the {@link Location class comment} for a     * description of strata).     *     * @param stratum The stratum to retrieve information from     * or <code>null</code> for the declaring type's     * default stratum.     *     * @return an int specifying the line in the source, returns     * -1 if the information is not available; specifically, always     * returns -1 for native methods.     *     * @since 1.4     */    int lineNumber(String stratum);     /**     * Compares the specified Object with this Location for equality.     *     * @return true if the Object is a Location and if it refers to     * the same point in the same VM as this Location.     */    boolean equals(Object obj);     /**     * Returns the hash code value for this Location.     *     * @return the integer hash code     */    int hashCode();}