001 /* MBeanConstructorInfo.java -- Information about a bean's constructor.
002 Copyright (C) 2006 Free Software Foundation, Inc.
003
004 This file is part of GNU Classpath.
005
006 GNU Classpath is free software; you can redistribute it and/or modify
007 it under the terms of the GNU General Public License as published by
008 the Free Software Foundation; either version 2, or (at your option)
009 any later version.
010
011 GNU Classpath is distributed in the hope that it will be useful, but
012 WITHOUT ANY WARRANTY; without even the implied warranty of
013 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
014 General Public License for more details.
015
016 You should have received a copy of the GNU General Public License
017 along with GNU Classpath; see the file COPYING. If not, write to the
018 Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
019 02110-1301 USA.
020
021 Linking this library statically or dynamically with other modules is
022 making a combined work based on this library. Thus, the terms and
023 conditions of the GNU General Public License cover the whole
024 combination.
025
026 As a special exception, the copyright holders of this library give you
027 permission to link this library with independent modules to produce an
028 executable, regardless of the license terms of these independent
029 modules, and to copy and distribute the resulting executable under
030 terms of your choice, provided that you also meet, for each linked
031 independent module, the terms and conditions of the license of that
032 module. An independent module is a module which is not derived from
033 or based on this library. If you modify this library, you may extend
034 this exception to your version of the library, but you are not
035 obligated to do so. If you do not wish to do so, delete this
036 exception statement from your version. */
037
038 package javax.management;
039
040 import java.lang.reflect.Constructor;
041 import java.lang.reflect.Type;
042
043 import java.util.Arrays;
044
045 /**
046 * Describes the constructors of a management bean.
047 * The information in this class is immutable as standard.
048 * Of course, subclasses may change this, but this
049 * behaviour is not recommended.
050 *
051 * @author Andrew John Hughes (gnu_andrew@member.fsf.org)
052 * @since 1.5
053 */
054 public class MBeanConstructorInfo
055 extends MBeanFeatureInfo
056 implements Cloneable
057 {
058
059 /**
060 * Compatible with JDK 1.5
061 */
062 private static final long serialVersionUID = 4433990064191844427L;
063
064 /**
065 * The signature of the constructor i.e. the argument types.
066 */
067 private MBeanParameterInfo[] signature;
068
069 /**
070 * Constructs a @link{MBeanConstructorInfo} with the specified
071 * description using the given constructor. Each parameter is
072 * described merely by its type; the name and description are
073 * <code>null</code>.
074 *
075 * @param desc a description of the attribute.
076 * @param cons the constructor.
077 */
078 public MBeanConstructorInfo(String desc, Constructor cons)
079 {
080 super(cons.getName(), desc);
081 Type[] paramTypes = cons.getGenericParameterTypes();
082 signature = new MBeanParameterInfo[paramTypes.length];
083 for (int a = 0; a < paramTypes.length; ++a)
084 {
085 Type t = paramTypes[a];
086 if (t instanceof Class)
087 signature[a] = new MBeanParameterInfo(null,
088 ((Class) t).getName(),
089 null);
090 else
091 signature[a] = new MBeanParameterInfo(null, t.toString(), null);
092 }
093 }
094
095 /**
096 * Constructs a @link{MBeanConstructorInfo} with the specified
097 * name, description and parameter information. A <code>null</code>
098 * value for the parameter information is the same as passing in
099 * an empty array. A copy of the parameter array is taken, so
100 * later changes have no effect.
101 *
102 * @param name the name of the constructor.
103 * @param desc a description of the constructor.
104 * @param sig the signature of the constructor, as a series
105 * of {@link MBeanParameterInfo} objects, one for
106 * each parameter.
107 */
108 public MBeanConstructorInfo(String name, String desc,
109 MBeanParameterInfo[] sig)
110 {
111 super(name, desc);
112 if (sig == null)
113 signature = new MBeanParameterInfo[0];
114 else
115 {
116 signature = new MBeanParameterInfo[sig.length];
117 System.arraycopy(sig, 0, signature, 0, sig.length);
118 }
119 }
120
121 /**
122 * Returns a clone of this instance. The clone is created
123 * using just the method provided by {@link java.lang.Object}.
124 * Thus, the clone is just a shallow clone as returned by
125 * that method, and does not contain any deeper cloning based
126 * on the subject of this class.
127 *
128 * @return a clone of this instance.
129 * @see java.lang.Cloneable
130 */
131 public Object clone()
132 {
133 try
134 {
135 return super.clone();
136 }
137 catch (CloneNotSupportedException e)
138 {
139 /* This shouldn't happen; we implement Cloneable */
140 throw new IllegalStateException("clone() called on " +
141 "non-cloneable object.");
142 }
143 }
144
145 /**
146 * Compares this feature with the supplied object. This returns
147 * true iff the object is an instance of {@link
148 * MBeanConstructorInfo}, {@link Object#equals()} returns true for a
149 * comparison of both the name and description of this notification
150 * with that of the specified object (performed by the superclass),
151 * and the two signature arrays contain the same elements in the
152 * same order (but one may be longer than the other).
153 *
154 * @param obj the object to compare.
155 * @return true if the object is a {@link MBeanConstructorInfo}
156 * instance,
157 * <code>name.equals(object.getName())</code>,
158 * <code>description.equals(object.getDescription())</code>
159 * and the corresponding elements of the signature arrays are
160 * equal.
161 */
162 public boolean equals(Object obj)
163 {
164 if (!(obj instanceof MBeanConstructorInfo))
165 return false;
166 if (!(super.equals(obj)))
167 return false;
168 MBeanConstructorInfo o = (MBeanConstructorInfo) obj;
169 MBeanParameterInfo[] sig = o.getSignature();
170 for (int a = 0; a < signature.length; ++a)
171 {
172 if (a == sig.length)
173 return true;
174 if (!(signature[a].equals(sig[a])))
175 return false;
176 }
177 return true;
178 }
179
180 /**
181 * Returns the constructor's signature, in the form of
182 * information on each parameter. Each parameter is
183 * described by an instance of {@link MBeanParameterInfo}.
184 * The returned array is a shallow copy of the array used
185 * by this instance, so changing which elements are stored
186 * in the array won't affect the array used by this, but
187 * changing the actual elements will affect the ones used
188 * here.
189 *
190 * @return an array of {@link MBeanParameterInfo} objects,
191 * describing the constructor parameters.
192 */
193 public MBeanParameterInfo[] getSignature()
194 {
195 return (MBeanParameterInfo[]) signature.clone();
196 }
197
198 /**
199 * Returns the hashcode of the constructor information as the sum
200 * of the hashcode of the superclass and the hashcode of the parameter
201 * array.
202 *
203 * @return the hashcode of the constructor information.
204 */
205 public int hashCode()
206 {
207 return super.hashCode() + Arrays.hashCode(signature);
208 }
209
210 /**
211 * <p>
212 * Returns a textual representation of this instance. This
213 * is constructed using the class name
214 * (<code>javax.management.MBeanConstructorInfo</code>),
215 * the name and description of the constructor and the
216 * contents of the array of parameters.
217 * </p>
218 * <p>
219 * As instances of this class are immutable, the return value
220 * is computed just once for each instance and reused
221 * throughout its life.
222 * </p>
223 *
224 * @return a @link{java.lang.String} instance representing
225 * the instance in textual form.
226 */
227 public String toString()
228 {
229 if (string == null)
230 {
231 super.toString();
232 string = string.substring(0, string.length() - 1)
233 + ",signature=" + Arrays.toString(signature)
234 + "]";
235 }
236 return string;
237 }
238
239 }