/* * Copyright (c) 1998, 2006, 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; /** * The mirror for a value in the target VM. * This interface is the root of a * value hierarchy encompassing primitive values and object values. * <P> * Some examples of where values may be accessed: * <BLOCKQUOTE><TABLE SUMMARY="layout"> * <TR> *   <TD>{@link ObjectReference#getValue(com.sun.jdi.Field) *                 ObjectReference.getValue(Field)} *   <TD>- value of a field * <TR> *   <TD>{@link StackFrame#getValue(com.sun.jdi.LocalVariable) *                 StackFrame.getValue(LocalVariable)} *   <TD>- value of a variable * <TR> *   <TD>{@link VirtualMachine#mirrorOf(double) *                 VirtualMachine.mirrorOf(double)} *   <TD>- created in the target VM by the JDI client * <TR> *   <TD>{@link com.sun.jdi.event.ModificationWatchpointEvent#valueToBe() *                 ModificationWatchpointEvent.valueToBe()} *   <TD>- returned with an event * </TABLE></BLOCKQUOTE> * <P> * The following table illustrates which subinterfaces of Value * are used to mirror values in the target VM -- * <TABLE BORDER=1 SUMMARY="Maps each kind of value to a mirrored *  instance of a subinterface of Value"> * <TR BGCOLOR="#EEEEFF"> *   <TH id="primval" colspan=4>Subinterfaces of {@link PrimitiveValue}</TH> * <TR BGCOLOR="#EEEEFF"> *   <TH id="kind"     align="left">Kind of value</TH> *   <TH id="example"  align="left">For example -<br>expression in target</TH> *   <TH id="mirrored" align="left">Is mirrored as an<br>instance of</TH> *   <TH id="type"     align="left">{@link Type} of value<br>{@link #type() Value.type()}</TH> * <TR> *   <TD headers="primval kind">     a boolean</TD> *   <TD headers="primval example">  <CODE>true</CODE></TD> *   <TD headers="primval mirrored"> {@link BooleanValue}</TD> *   <TD headers="primval type">     {@link BooleanType}</TD> * <TR> *   <TD headers="primval kind">     a byte</TD> *   <TD headers="primval example">  <CODE>(byte)4</CODE></TD> *   <TD headers="primval mirrored"> {@link ByteValue}</TD> *   <TD headers="primval type">     {@link ByteType}</TD> * <TR> *   <TD headers="primval kind">     a char</TD> *   <TD headers="primval example">  <CODE>'a'</CODE></TD> *   <TD headers="primval mirrored"> {@link CharValue}</TD> *   <TD headers="primval type">     {@link CharType}</TD> * <TR> *   <TD headers="primval kind">     a double</TD> *   <TD headers="primval example">  <CODE>3.1415926</CODE></TD> *   <TD headers="primval mirrored"> {@link DoubleValue}</TD> *   <TD headers="primval type">     {@link DoubleType}</TD> * <TR> *   <TD headers="primval kind">     a float</TD> *   <TD headers="primval example">  <CODE>2.5f</CODE></TD> *   <TD headers="primval mirrored"> {@link FloatValue}</TD> *   <TD headers="primval type">     {@link FloatType}</TD> * <TR> *   <TD headers="primval kind">     an int</TD> *   <TD headers="primval example">  <CODE>22</CODE></TD> *   <TD headers="primval mirrored"> {@link IntegerValue}</TD> *   <TD headers="primval type">     {@link IntegerType}</TD> * <TR> *   <TD headers="primval kind">     a long</TD> *   <TD headers="primval example">  <CODE>1024L</CODE></TD> *   <TD headers="primval mirrored"> {@link LongValue}</TD> *   <TD headers="primval type">     {@link LongType}</TD> * <TR> *   <TD headers="primval kind">     a short</TD> *   <TD headers="primval example">  <CODE>(short)12</CODE></TD> *   <TD headers="primval mirrored"> {@link ShortValue}</TD> *   <TD headers="primval type">     {@link ShortType}</TD> * <TR> *   <TD headers="primval kind">     a void</TD> *   <TD headers="primval example">  <CODE>&nbsp;</CODE></TD> *   <TD headers="primval mirrored"> {@link VoidValue}</TD> *   <TD headers="primval type">     {@link VoidType}</TD> * <TR BGCOLOR="#EEEEFF"> *   <TH id="objref" colspan=4>Subinterfaces of {@link ObjectReference}</TH> * <TR BGCOLOR="#EEEEFF"> *   <TH id="kind2"     align="left">Kind of value</TH> *   <TH id="example2"  align="left">For example -<br>expression in target</TH> *   <TH id="mirrored2" align="left">Is mirrored as an<br>instance of</TH> *   <TH id="type2"     align="left">{@link Type} of value<br>{@link #type() Value.type()}</TH> * <TR> *   <TD headers="objref kind2">     a class instance</TD> *   <TD headers="objref example2">  <CODE>this</CODE></TD> *   <TD headers="objref mirrored2"> {@link ObjectReference}</TD> *   <TD headers="objref type2">     {@link ClassType}</TD> * <TR> *   <TD headers="objref kind2">     an array</TD> *   <TD headers="objref example2">  <CODE>new int[5]</CODE></TD> *   <TD headers="objref mirrored2"> {@link ArrayReference}</TD> *   <TD headers="objref type2">     {@link ArrayType}</TD> * <TR> *   <TD headers="objref kind2">     a string</TD> *   <TD headers="objref example2">  <CODE>"hello"</CODE></TD> *   <TD headers="objref mirrored2"> {@link StringReference}</TD> *   <TD headers="objref type2">     {@link ClassType}</TD> * <TR> *   <TD headers="objref kind2">     a thread</TD> *   <TD headers="objref example2">  <CODE>Thread.currentThread()</CODE></TD> *   <TD headers="objref mirrored2"> {@link ThreadReference}</TD> *   <TD headers="objref type2">     {@link ClassType}</TD> * <TR> *   <TD headers="objref kind2">     a thread group</TD> *   <TD headers="objref example2">  <CODE>Thread.currentThread()<br>&nbsp;&nbsp;.getThreadGroup()</CODE></TD> *   <TD headers="objref mirrored2"> {@link ThreadGroupReference}</TD> *   <TD headers="objref type2">     {@link ClassType}</TD> * <TR> *   <TD headers="objref kind2">     a <CODE>java.lang.Class</CODE><br>instance</TD> *   <TD headers="objref example2">  <CODE>this.getClass()</CODE></TD> *   <TD headers="objref mirrored2"> {@link ClassObjectReference}</TD> *   <TD headers="objref type2">     {@link ClassType}</TD> * <TR> *   <TD headers="objref kind2">     a class loader</TD> *   <TD headers="objref example2">  <CODE>this.getClass()<br>&nbsp;&nbsp;.getClassLoader() </CODE></TD> *   <TD headers="objref mirrored2"> {@link ClassLoaderReference}</TD> *   <TD headers="objref type2">     {@link ClassType}</TD> * <TR BGCOLOR="#EEEEFF"> *   <TH id="other" colspan=4>Other</TH> * <TR BGCOLOR="#EEEEFF"> *   <TH id="kind3"     align="left">Kind of value</TD> *   <TH id="example3"  align="left">For example -<br>expression in target</TD> *   <TH id="mirrored3" align="left">Is mirrored as</TD> *   <TH id="type3"     align="left">{@link Type} of value</TD> * <TR> *   <TD headers="other kind3">     null</TD> *   <TD headers="other example3">  <CODE>null</CODE></TD> *   <TD headers="other mirrored3"> <CODE>null</CODE></TD> *   <TD headers="other type3">     n/a</TD> * </TABLE> * * @author Robert Field * @author Gordon Hirsch * @author James McIlree * @since  1.3 */ public interface Value extends Mirror{    /**     * Returns the run-time type of this value.     *     * @see Type     * @return a {@link Type} which mirrors the value's type in the     * target VM.     */    Type type();}