1 /*
2 * Copyright (c) 1998, 2004, 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 class or instance variable in the target VM.
30 * See {@link TypeComponent}
31 * for general information about Field and Method mirrors.
32 *
33 * @see ObjectReference
34 * @see ReferenceType
35 *
36 * @author Robert Field
37 * @author Gordon Hirsch
38 * @author James McIlree
39 * @since 1.3
40 */
41 @jdk.Supported
42 public interface Field extends TypeComponent, Comparable<Field> {
43
44 /**
45 * Returns a text representation of the type
46 * of this field.
47 * Where the type is the type specified in the declaration
48 * of this field.
49 * <P>
50 * This type name is always available even if
51 * the type has not yet been created or loaded.
52 *
53 * @return a String representing the
54 * type of this field.
55 */
56 String typeName();
57
58 /**
59 * Returns the type of this field.
60 * Where the type is the type specified in the declaration
61 * of this field.
62 * <P>
63 * For example, if a target class defines:
64 * <PRE>
65 * short s;
66 * Date d;
67 * byte[] ba;</PRE>
68 * And the JDI client defines these <CODE>Field</CODE> objects:
69 * <PRE>
70 * Field sField = targetClass.fieldByName("s");
71 * Field dField = targetClass.fieldByName("d");
72 * Field baField = targetClass.fieldByName("ba");</PRE>
73 * to mirror the corresponding fields, then <CODE>sField.type()</CODE>
74 * is a {@link ShortType}, <CODE>dField.type()</CODE> is the
75 * {@link ReferenceType} for <CODE>java.util.Date</CODE> and
76 * <CODE>((ArrayType)(baField.type())).componentType()</CODE> is a
77 * {@link ByteType}.
78 * <P>
79 * Note: if the type of this field is a reference type (class,
80 * interface, or array) and it has not been created or loaded
81 * by the declaring type's class loader - that is,
82 * {@link TypeComponent#declaringType <CODE>declaringType()</CODE>}
83 * <CODE>.classLoader()</CODE>,
84 * then ClassNotLoadedException will be thrown.
85 * Also, a reference type may have been loaded but not yet prepared,
86 * in which case the type will be returned
87 * but attempts to perform some operations on the returned type
88 * (e.g. {@link ReferenceType#fields() fields()}) will throw
89 * a {@link ClassNotPreparedException}.
90 * Use {@link ReferenceType#isPrepared()} to determine if
91 * a reference type is prepared.
92 *
93 * @see Type
94 * @return the {@link Type} of this field.
95 * @throws ClassNotLoadedException if the type has not yet been loaded
96 * or created through the appropriate class loader.
97 */
98 Type type() throws ClassNotLoadedException;
99
100 /**
101 * Determine if this is a transient field.
102 *
103 * @return <code>true</code> if this field is transient; false otherwise.
104 */
105 boolean isTransient();
106
107 /**
108 * Determine if this is a volatile field.
109 *
110 * @return <code>true</code> if this field is volatile; false otherwise.
111 */
112 boolean isVolatile();
113
114 /**
115 * Determine if this is a field that represents an enum constant.
116 * @return <code>true</code> if this field represents an enum constant;
117 * false otherwise.
118 */
119 boolean isEnumConstant();
120
121 /**
122 * Compares the specified Object with this field for equality.
123 *
124 * @return true if the Object is a Field and if both
125 * mirror the same field (declared in the same class or interface, in
126 * the same VM).
127 */
128 boolean equals(Object obj);
129
130 /**
131 * Returns the hash code value for this Field.
132 *
133 * @return the integer hash code
134 */
135 int hashCode();
136 }