1 /*
2 * $Id: MethodExpressionMethodBindingAdapter.java,v 1.7 2007/04/27 22:00:12 ofung Exp $
3 */
4
5 /*
6 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
7 *
8 * Copyright 1997-2007 Sun Microsystems, Inc. All rights reserved.
9 *
10 * The contents of this file are subject to the terms of either the GNU
11 * General Public License Version 2 only ("GPL") or the Common Development
12 * and Distribution License("CDDL") (collectively, the "License"). You
13 * may not use this file except in compliance with the License. You can obtain
14 * a copy of the License at https://glassfish.dev.java.net/public/CDDL+GPL.html
15 * or glassfish/bootstrap/legal/LICENSE.txt. See the License for the specific
16 * language governing permissions and limitations under the License.
17 *
18 * When distributing the software, include this License Header Notice in each
19 * file and include the License file at glassfish/bootstrap/legal/LICENSE.txt.
20 * Sun designates this particular file as subject to the "Classpath" exception
21 * as provided by Sun in the GPL Version 2 section of the License file that
22 * accompanied this code. If applicable, add the following below the License
23 * Header, with the fields enclosed by brackets [] replaced by your own
24 * identifying information: "Portions Copyrighted [year]
25 * [name of copyright owner]"
26 *
27 * Contributor(s):
28 *
29 * If you wish your version of this file to be governed by only the CDDL or
30 * only the GPL Version 2, indicate your decision by adding "[Contributor]
31 * elects to include this software in this distribution under the [CDDL or GPL
32 * Version 2] license." If you don't indicate a single choice of license, a
33 * recipient has the option to distribute your version of this file under
34 * either the CDDL, the GPL Version 2 or to extend the choice of license to
35 * its licensees as provided above. However, if you add GPL Version 2 code
36 * and therefore, elected the GPL Version 2 license, then the option applies
37 * only if the new code is made subject to such option by the copyright
38 * holder.
39 */
40
41 package javax.faces.component;
42
43 import javax.el.MethodExpression;
44 import javax.el.ELException;
45 import javax.el.ELContext;
46 import javax.el.MethodInfo;
47 import javax.faces.el.MethodBinding;
48 import javax.faces.context.FacesContext;
49 import javax.faces.component.StateHolder;
50 import javax.el.ELContext;
51 import javax.el.ExpressionFactory;
52 import javax.el.ValueExpression;
53
54 import java.util.Arrays;
55 import java.lang.reflect.Method;
56 import java.io.Serializable;
57
58 /**
59 * <p>Wrap a MethodBinding instance and expose it as a
60 * MethodExpression.</p>
61 */
62
63 class MethodExpressionMethodBindingAdapter extends MethodExpression implements Serializable, StateHolder {
64
65 private static final long serialVersionUID = -1822420567946048452L;
66
67 public MethodExpressionMethodBindingAdapter() {} // for StateHolder
68
69 private MethodBinding binding = null;
70
71 MethodExpressionMethodBindingAdapter(MethodBinding binding) {
72 assert(null != binding);
73 this.binding = binding;
74 }
75
76 //
77 // Methods from MethodExpression
78 //
79
80 private transient MethodInfo info = null;
81
82 public MethodInfo getMethodInfo(ELContext context) throws ELException {
83 assert(null != binding);
84
85 if (context == null) {
86 throw new NullPointerException("ELContext -> null");
87 }
88
89 if (null == info) {
90 FacesContext facesContext = (FacesContext)
91 context.getContext(FacesContext.class);
92 if (null != facesContext) {
93 try {
94 //PENDING - we should find a way to provide more information
95 info = new MethodInfo(null, binding.getType(facesContext), null);
96 }
97 catch (Exception e) {
98 throw new ELException(e);
99 }
100 }
101 }
102
103 return info;
104 }
105
106 public Object invoke(ELContext context, Object[] params) throws ELException {
107 assert(null != binding);
108
109 if (context == null) {
110 throw new NullPointerException("ELContext -> null");
111 }
112
113 Object result = null;
114 FacesContext facesContext = (FacesContext)
115 context.getContext(FacesContext.class);
116 if (null != facesContext) {
117 try {
118 result = binding.invoke(facesContext, params);
119 }
120 catch (Exception e) {
121 throw new ELException(e);
122 }
123 }
124 return result;
125 }
126
127 public String getExpressionString() {
128 assert(null != binding);
129 return binding.getExpressionString();
130
131 }
132
133 public boolean isLiteralText() {
134 assert (binding != null);
135 String expr = binding.getExpressionString();
136 return (!(expr.startsWith("#{")
137 && expr.endsWith("}")));
138 }
139
140 public boolean equals(Object other) {
141
142 if (other == this) {
143 return true;
144 }
145
146 if (other instanceof MethodExpressionMethodBindingAdapter) {
147 MethodBinding ob = ((MethodExpressionMethodBindingAdapter) other).getWrapped();
148 return (binding.equals(ob));
149 } else if (other instanceof MethodExpression) {
150 MethodExpression expression = (MethodExpression) other;
151
152 // We'll need to do a little leg work to determine
153 // if the MethodBinding is equivalent to the
154 // wrapped MethodExpression
155 String expr = binding.getExpressionString();
156 int idx = expr.indexOf('.');
157 String target = expr.substring(0, idx).substring(2);
158 String t = expr.substring(idx + 1);
159 String method = t.substring(0, (t.length() - 1));
160
161 FacesContext context = FacesContext.getCurrentInstance();
162 ELContext elContext = context.getELContext();
163 MethodInfo controlInfo = expression.getMethodInfo(elContext);
164
165 // ensure the method names are the same
166 if (!controlInfo.getName().equals(method)) {
167 return false;
168 }
169
170 // Using the target, create an expression and evaluate
171 // it.
172 ExpressionFactory factory = context.getApplication().getExpressionFactory();
173 ValueExpression ve = factory.createValueExpression(elContext,
174 "#{" + target + '}',
175 Object.class);
176 if (ve == null) {
177 return false;
178 }
179
180 Object result = ve.getValue(elContext);
181
182 if (result == null) {
183 return false;
184 }
185
186
187 // Get all of the methods with the matching name and try
188 // to find a match based on controlInfo's return and parameter
189 // types
190 Method[] methods = result.getClass().getMethods();
191 for (Method meth : methods) {
192 if (meth.getName().equals(method)
193 && meth.getReturnType().equals(controlInfo.getReturnType())
194 && Arrays.equals(meth.getParameterTypes(),
195 controlInfo.getParamTypes())) {
196 return true;
197 }
198 }
199 }
200 return false;
201
202 }
203
204 public int hashCode() {
205 assert(null != binding);
206
207 return binding.hashCode();
208 }
209
210 public String getDelimiterSyntax() {
211 // PENDING (visvan) Implementation
212 return "";
213 }
214
215 //
216 // Methods from StateHolder
217 //
218
219
220
221 public Object saveState(FacesContext context) {
222 if (context == null) {
223 throw new NullPointerException();
224 }
225 Object result = null;
226 if (!tranzient) {
227 if (binding instanceof StateHolder) {
228 Object [] stateStruct = new Object[2];
229
230 // save the actual state of our wrapped binding
231 stateStruct[0] = ((StateHolder)binding).saveState(context);
232 // save the class name of the binding impl
233 stateStruct[1] = binding.getClass().getName();
234
235 result = stateStruct;
236 }
237 else {
238 result = binding;
239 }
240 }
241
242 return result;
243 }
244
245 public void restoreState(FacesContext context, Object state) {
246 if (context == null) {
247 throw new NullPointerException();
248 }
249 // if we have state
250 if (null == state) {
251 return;
252 }
253
254 if (!(state instanceof MethodBinding)) {
255 Object [] stateStruct = (Object []) state;
256 Object savedState = stateStruct[0];
257 String className = stateStruct[1].toString();
258 MethodBinding result = null;
259
260 Class toRestoreClass = null;
261 if (null != className) {
262 try {
263 toRestoreClass = loadClass(className, this);
264 }
265 catch (ClassNotFoundException e) {
266 throw new IllegalStateException(e.getMessage());
267 }
268
269 if (null != toRestoreClass) {
270 try {
271 result =
272 (MethodBinding) toRestoreClass.newInstance();
273 }
274 catch (InstantiationException e) {
275 throw new IllegalStateException(e.getMessage());
276 }
277 catch (IllegalAccessException a) {
278 throw new IllegalStateException(a.getMessage());
279 }
280 }
281
282 if (null != result && null != savedState) {
283 // don't need to check transient, since that was
284 // done on the saving side.
285 ((StateHolder)result).restoreState(context, savedState);
286 }
287 binding = result;
288 }
289 }
290 else {
291 binding = (MethodBinding) state;
292 }
293 }
294
295 private boolean tranzient = false;
296
297 public boolean isTransient() {
298 return tranzient;
299 }
300
301 public void setTransient(boolean newTransientMethod) {
302 tranzient = newTransientMethod;
303 }
304
305 //
306 // Helper methods for StateHolder
307 //
308
309 private static Class loadClass(String name,
310 Object fallbackClass) throws ClassNotFoundException {
311 ClassLoader loader =
312 Thread.currentThread().getContextClassLoader();
313 if (loader == null) {
314 loader = fallbackClass.getClass().getClassLoader();
315 }
316 return Class.forName(name, true, loader);
317 }
318
319
320 //
321 // methods used by classes aware of this class's wrapper nature
322 //
323
324 public MethodBinding getWrapped() {
325 return binding;
326 }
327
328 }