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 26package com.sun.jdi; 27 28/** 29 * The mirror for a value in the target VM. 30 * This interface is the root of a 31 * value hierarchy encompassing primitive values and object values. 32 * <P> 33 * Some examples of where values may be accessed: 34 * <BLOCKQUOTE><TABLE><CAPTION style="display:none">layout</CAPTION> 35 * <TR> 36 * <TD>{@link ObjectReference#getValue(com.sun.jdi.Field) 37 * ObjectReference.getValue(Field)} 38 * <TD>- value of a field 39 * <TR> 40 * <TD>{@link StackFrame#getValue(com.sun.jdi.LocalVariable) 41 * StackFrame.getValue(LocalVariable)} 42 * <TD>- value of a variable 43 * <TR> 44 * <TD>{@link VirtualMachine#mirrorOf(double) 45 * VirtualMachine.mirrorOf(double)} 46 * <TD>- created in the target VM by the JDI client 47 * <TR> 48 * <TD>{@link com.sun.jdi.event.ModificationWatchpointEvent#valueToBe() 49 * ModificationWatchpointEvent.valueToBe()} 50 * <TD>- returned with an event 51 * </TABLE></BLOCKQUOTE> 52 * <P> 53 * The following table illustrates which subinterfaces of Value 54 * are used to mirror values in the target VM -- 55 * <TABLE BORDER="1"> 56 * <CAPTION style="display:none">Maps each kind of value to a mirrored 57 * instance of a subinterface of Value</CAPTION> 58 * <TR style="background-color:#EEEEFF"> 59 * <TH id="primval" colspan=4>Subinterfaces of {@link PrimitiveValue}</TH> 60 * <TR style="background-color:#EEEEFF"> 61 * <TH id="kind" style="text-align:left">Kind of value</TH> 62 * <TH id="example" style="text-align:left">For example -<br>expression in target</TH> 63 * <TH id="mirrored" style="text-align:left">Is mirrored as an<br>instance of</TH> 64 * <TH id="type" style="text-align:left">{@link Type} of value<br>{@link #type() Value.type()}</TH> 65 * <TR> 66 * <TD headers="primval kind"> a boolean</TD> 67 * <TD headers="primval example"> {@code true}</TD> 68 * <TD headers="primval mirrored"> {@link BooleanValue}</TD> 69 * <TD headers="primval type"> {@link BooleanType}</TD> 70 * <TR> 71 * <TD headers="primval kind"> a byte</TD> 72 * <TD headers="primval example"> {@code (byte)4}</TD> 73 * <TD headers="primval mirrored"> {@link ByteValue}</TD> 74 * <TD headers="primval type"> {@link ByteType}</TD> 75 * <TR> 76 * <TD headers="primval kind"> a char</TD> 77 * <TD headers="primval example"> {@code 'a'}</TD> 78 * <TD headers="primval mirrored"> {@link CharValue}</TD> 79 * <TD headers="primval type"> {@link CharType}</TD> 80 * <TR> 81 * <TD headers="primval kind"> a double</TD> 82 * <TD headers="primval example"> {@code 3.1415926}</TD> 83 * <TD headers="primval mirrored"> {@link DoubleValue}</TD> 84 * <TD headers="primval type"> {@link DoubleType}</TD> 85 * <TR> 86 * <TD headers="primval kind"> a float</TD> 87 * <TD headers="primval example"> {@code 2.5f}</TD> 88 * <TD headers="primval mirrored"> {@link FloatValue}</TD> 89 * <TD headers="primval type"> {@link FloatType}</TD> 90 * <TR> 91 * <TD headers="primval kind"> an int</TD> 92 * <TD headers="primval example"> {@code 22}</TD> 93 * <TD headers="primval mirrored"> {@link IntegerValue}</TD> 94 * <TD headers="primval type"> {@link IntegerType}</TD> 95 * <TR> 96 * <TD headers="primval kind"> a long</TD> 97 * <TD headers="primval example"> {@code 1024L}</TD> 98 * <TD headers="primval mirrored"> {@link LongValue}</TD> 99 * <TD headers="primval type"> {@link LongType}</TD> 100 * <TR> 101 * <TD headers="primval kind"> a short</TD> 102 * <TD headers="primval example"> {@code (short)12}</TD> 103 * <TD headers="primval mirrored"> {@link ShortValue}</TD> 104 * <TD headers="primval type"> {@link ShortType}</TD> 105 * <TR> 106 * <TD headers="primval kind"> a void</TD> 107 * <TD headers="primval example"> </TD> 108 * <TD headers="primval mirrored"> {@link VoidValue}</TD> 109 * <TD headers="primval type"> {@link VoidType}</TD> 110 * <TR style="background-color:#EEEEFF"> 111 * <TH id="objref" colspan=4>Subinterfaces of {@link ObjectReference}</TH> 112 * <TR style="background-color:#EEEEFF"> 113 * <TH id="kind2" style="text-align:left">Kind of value</TH> 114 * <TH id="example2" style="text-align:left">For example -<br>expression in target</TH> 115 * <TH id="mirrored2" style="text-align:left">Is mirrored as an<br>instance of</TH> 116 * <TH id="type2" style="text-align:left">{@link Type} of value<br>{@link #type() Value.type()}</TH> 117 * <TR> 118 * <TD headers="objref kind2"> a class instance</TD> 119 * <TD headers="objref example2"> {@code this}</TD> 120 * <TD headers="objref mirrored2"> {@link ObjectReference}</TD> 121 * <TD headers="objref type2"> {@link ClassType}</TD> 122 * <TR> 123 * <TD headers="objref kind2"> an array</TD> 124 * <TD headers="objref example2"> {@code new int[5]}</TD> 125 * <TD headers="objref mirrored2"> {@link ArrayReference}</TD> 126 * <TD headers="objref type2"> {@link ArrayType}</TD> 127 * <TR> 128 * <TD headers="objref kind2"> a string</TD> 129 * <TD headers="objref example2"> {@code "hello"}</TD> 130 * <TD headers="objref mirrored2"> {@link StringReference}</TD> 131 * <TD headers="objref type2"> {@link ClassType}</TD> 132 * <TR> 133 * <TD headers="objref kind2"> a thread</TD> 134 * <TD headers="objref example2"> {@code Thread.currentThread()}</TD> 135 * <TD headers="objref mirrored2"> {@link ThreadReference}</TD> 136 * <TD headers="objref type2"> {@link ClassType}</TD> 137 * <TR> 138 * <TD headers="objref kind2"> a thread group</TD> 139 * <TD headers="objref example2"> {@code Thread.currentThread()}<br> {@code .getThreadGroup()}</TD> 140 * <TD headers="objref mirrored2"> {@link ThreadGroupReference}</TD> 141 * <TD headers="objref type2"> {@link ClassType}</TD> 142 * <TR> 143 * <TD headers="objref kind2"> a {@code java.lang.Class}<br>instance</TD> 144 * <TD headers="objref example2"> {@code this.getClass()}</TD> 145 * <TD headers="objref mirrored2"> {@link ClassObjectReference}</TD> 146 * <TD headers="objref type2"> {@link ClassType}</TD> 147 * <TR> 148 * <TD headers="objref kind2"> a class loader</TD> 149 * <TD headers="objref example2"> {@code this.getClass()}<br> {@code .getClassLoader()}</TD> 150 * <TD headers="objref mirrored2"> {@link ClassLoaderReference}</TD> 151 * <TD headers="objref type2"> {@link ClassType}</TD> 152 * <TR style="background-color:#EEEEFF"> 153 * <TH id="other" colspan=4>Other</TH> 154 * <TR style="background-color:#EEEEFF"> 155 * <TD id="kind3" style="text-align:left">Kind of value</TD> 156 * <TD id="example3" style="text-align:left">For example -<br>expression in target</TD> 157 * <TD id="mirrored3" style="text-align:left">Is mirrored as</TD> 158 * <TD id="type3" style="text-align:left">{@link Type} of value</TD> 159 * <TR> 160 * <TD headers="other kind3"> null</TD> 161 * <TD headers="other example3"> {@code null}</TD> 162 * <TD headers="other mirrored3"> {@code null}</TD> 163 * <TD headers="other type3"> n/a</TD> 164 * </TABLE> 165 * 166 * @author Robert Field 167 * @author Gordon Hirsch 168 * @author James McIlree 169 * @since 1.3 170 */ 171 172public interface Value extends Mirror { 173 /** 174 * Returns the run-time type of this value. 175 * 176 * @see Type 177 * @return a {@link Type} which mirrors the value's type in the 178 * target VM. 179 */ 180 Type type(); 181} 182