J. Duke | 319a3b9 | 2007-12-01 00:00:00 +0000 | [diff] [blame^] | 1 | /* |
| 2 | * Copyright 1996-2003 Sun Microsystems, Inc. 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. Sun designates this |
| 8 | * particular file as subject to the "Classpath" exception as provided |
| 9 | * by Sun 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, |
| 22 | * CA 95054 USA or visit www.sun.com if you need additional information or |
| 23 | * have any questions. |
| 24 | */ |
| 25 | |
| 26 | package java.beans; |
| 27 | |
| 28 | import java.lang.ref.Reference; |
| 29 | import java.lang.ref.WeakReference; |
| 30 | |
| 31 | import java.lang.reflect.Method; |
| 32 | |
| 33 | import java.util.List; |
| 34 | import java.util.ArrayList; |
| 35 | |
| 36 | /** |
| 37 | * A MethodDescriptor describes a particular method that a Java Bean |
| 38 | * supports for external access from other components. |
| 39 | */ |
| 40 | |
| 41 | public class MethodDescriptor extends FeatureDescriptor { |
| 42 | |
| 43 | private Reference<Method> methodRef; |
| 44 | |
| 45 | private String[] paramNames; |
| 46 | |
| 47 | private List params; |
| 48 | |
| 49 | private ParameterDescriptor parameterDescriptors[]; |
| 50 | |
| 51 | /** |
| 52 | * Constructs a <code>MethodDescriptor</code> from a |
| 53 | * <code>Method</code>. |
| 54 | * |
| 55 | * @param method The low-level method information. |
| 56 | */ |
| 57 | public MethodDescriptor(Method method) { |
| 58 | this(method, null); |
| 59 | } |
| 60 | |
| 61 | |
| 62 | /** |
| 63 | * Constructs a <code>MethodDescriptor</code> from a |
| 64 | * <code>Method</code> providing descriptive information for each |
| 65 | * of the method's parameters. |
| 66 | * |
| 67 | * @param method The low-level method information. |
| 68 | * @param parameterDescriptors Descriptive information for each of the |
| 69 | * method's parameters. |
| 70 | */ |
| 71 | public MethodDescriptor(Method method, |
| 72 | ParameterDescriptor parameterDescriptors[]) { |
| 73 | setName(method.getName()); |
| 74 | setMethod(method); |
| 75 | this.parameterDescriptors = parameterDescriptors; |
| 76 | } |
| 77 | |
| 78 | /** |
| 79 | * Gets the method that this MethodDescriptor encapsualtes. |
| 80 | * |
| 81 | * @return The low-level description of the method |
| 82 | */ |
| 83 | public synchronized Method getMethod() { |
| 84 | Method method = getMethod0(); |
| 85 | if (method == null) { |
| 86 | Class cls = getClass0(); |
| 87 | if (cls != null) { |
| 88 | Class[] params = getParams(); |
| 89 | if (params == null) { |
| 90 | for (int i = 0; i < 3; i++) { |
| 91 | // Find methods for up to 2 params. We are guessing here. |
| 92 | // This block should never execute unless the classloader |
| 93 | // that loaded the argument classes disappears. |
| 94 | method = Introspector.findMethod(cls, getName(), i, null); |
| 95 | if (method != null) { |
| 96 | break; |
| 97 | } |
| 98 | } |
| 99 | } else { |
| 100 | method = Introspector.findMethod(cls, getName(), |
| 101 | params.length, params); |
| 102 | } |
| 103 | setMethod(method); |
| 104 | } |
| 105 | } |
| 106 | return method; |
| 107 | } |
| 108 | |
| 109 | private synchronized void setMethod(Method method) { |
| 110 | if (method == null) { |
| 111 | return; |
| 112 | } |
| 113 | if (getClass0() == null) { |
| 114 | setClass0(method.getDeclaringClass()); |
| 115 | } |
| 116 | setParams(getParameterTypes(getClass0(), method)); |
| 117 | this.methodRef = getSoftReference(method); |
| 118 | } |
| 119 | |
| 120 | private Method getMethod0() { |
| 121 | return (this.methodRef != null) |
| 122 | ? this.methodRef.get() |
| 123 | : null; |
| 124 | } |
| 125 | |
| 126 | private synchronized void setParams(Class[] param) { |
| 127 | if (param == null) { |
| 128 | return; |
| 129 | } |
| 130 | paramNames = new String[param.length]; |
| 131 | params = new ArrayList(param.length); |
| 132 | for (int i = 0; i < param.length; i++) { |
| 133 | paramNames[i] = param[i].getName(); |
| 134 | params.add(new WeakReference(param[i])); |
| 135 | } |
| 136 | } |
| 137 | |
| 138 | // pp getParamNames used as an optimization to avoid method.getParameterTypes. |
| 139 | String[] getParamNames() { |
| 140 | return paramNames; |
| 141 | } |
| 142 | |
| 143 | private synchronized Class[] getParams() { |
| 144 | Class[] clss = new Class[params.size()]; |
| 145 | |
| 146 | for (int i = 0; i < params.size(); i++) { |
| 147 | Reference ref = (Reference)params.get(i); |
| 148 | Class cls = (Class)ref.get(); |
| 149 | if (cls == null) { |
| 150 | return null; |
| 151 | } else { |
| 152 | clss[i] = cls; |
| 153 | } |
| 154 | } |
| 155 | return clss; |
| 156 | } |
| 157 | |
| 158 | /** |
| 159 | * Gets the ParameterDescriptor for each of this MethodDescriptor's |
| 160 | * method's parameters. |
| 161 | * |
| 162 | * @return The locale-independent names of the parameters. May return |
| 163 | * a null array if the parameter names aren't known. |
| 164 | */ |
| 165 | public ParameterDescriptor[] getParameterDescriptors() { |
| 166 | return parameterDescriptors; |
| 167 | } |
| 168 | |
| 169 | /* |
| 170 | public String toString() { |
| 171 | String message = "name=" + getName(); |
| 172 | Class cls = getClass0(); |
| 173 | if (cls != null) { |
| 174 | message += ", class="; |
| 175 | message += cls.getName(); |
| 176 | } |
| 177 | String[] names = getParamNames(); |
| 178 | if (names != null) { |
| 179 | for (int i = 0; i < names.length; i++) { |
| 180 | message += ", param=" + names[i]; |
| 181 | } |
| 182 | } |
| 183 | return message; |
| 184 | } */ |
| 185 | |
| 186 | /* |
| 187 | * Package-private constructor |
| 188 | * Merge two method descriptors. Where they conflict, give the |
| 189 | * second argument (y) priority over the first argument (x). |
| 190 | * @param x The first (lower priority) MethodDescriptor |
| 191 | * @param y The second (higher priority) MethodDescriptor |
| 192 | */ |
| 193 | |
| 194 | MethodDescriptor(MethodDescriptor x, MethodDescriptor y) { |
| 195 | super(x,y); |
| 196 | |
| 197 | methodRef = x.methodRef; |
| 198 | if (y.methodRef != null) { |
| 199 | methodRef = y.methodRef; |
| 200 | } |
| 201 | params = x.params; |
| 202 | if (y.params != null) { |
| 203 | params = y.params; |
| 204 | } |
| 205 | paramNames = x.paramNames; |
| 206 | if (y.paramNames != null) { |
| 207 | paramNames = y.paramNames; |
| 208 | } |
| 209 | |
| 210 | parameterDescriptors = x.parameterDescriptors; |
| 211 | if (y.parameterDescriptors != null) { |
| 212 | parameterDescriptors = y.parameterDescriptors; |
| 213 | } |
| 214 | } |
| 215 | |
| 216 | /* |
| 217 | * Package-private dup constructor |
| 218 | * This must isolate the new object from any changes to the old object. |
| 219 | */ |
| 220 | MethodDescriptor(MethodDescriptor old) { |
| 221 | super(old); |
| 222 | |
| 223 | methodRef = old.methodRef; |
| 224 | params = old.params; |
| 225 | paramNames = old.paramNames; |
| 226 | |
| 227 | if (old.parameterDescriptors != null) { |
| 228 | int len = old.parameterDescriptors.length; |
| 229 | parameterDescriptors = new ParameterDescriptor[len]; |
| 230 | for (int i = 0; i < len ; i++) { |
| 231 | parameterDescriptors[i] = new ParameterDescriptor(old.parameterDescriptors[i]); |
| 232 | } |
| 233 | } |
| 234 | } |
| 235 | |
| 236 | } |