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