1 /*
2 * $Id: ValueExpressionValueBindingAdapter.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.ValueExpression;
44 import javax.el.ELException;
45 import javax.el.ELContext;
46 import javax.faces.el.ValueBinding;
47 import javax.faces.context.FacesContext;
48 import javax.faces.component.StateHolder;
49
50 import java.io.Serializable;
51
52 /**
53 * <p>Wrap a ValueBinding instance and expose it as a
54 * ValueExpression.</p>
55 */
56
57 class ValueExpressionValueBindingAdapter extends ValueExpression implements Serializable, StateHolder {
58
59 private static final long serialVersionUID = 2388977392466671243L;
60
61 public ValueExpressionValueBindingAdapter() {}
62
63 private ValueBinding binding = null;
64
65 ValueExpressionValueBindingAdapter(ValueBinding binding) {
66 assert(null != binding);
67 this.binding = binding;
68 }
69
70 //
71 // Methods from ValueExpression
72 //
73
74 public Object getValue(ELContext context) throws ELException {
75 assert(null != binding);
76 if (context == null) {
77 throw new NullPointerException("ELContext -> null");
78 }
79 Object result = null;
80 FacesContext facesContext = (FacesContext)
81 context.getContext(FacesContext.class);
82 assert(null != facesContext);
83 try {
84 result = binding.getValue(facesContext);
85 }
86 catch (Throwable e) {
87 throw new ELException(e);
88 }
89 return result;
90 }
91
92 public void setValue(ELContext context, Object value) throws ELException {
93 assert(null != binding);
94 if (context == null) {
95 throw new NullPointerException("ELContext -> null");
96 }
97 FacesContext facesContext = (FacesContext)
98 context.getContext(FacesContext.class);
99 assert(null != facesContext);
100 try {
101 binding.setValue(facesContext, value);
102 }
103 catch (Throwable e) {
104 throw new ELException(e);
105 }
106 }
107
108
109 public boolean isReadOnly(ELContext context) throws ELException {
110 assert(null != binding);
111 if (context == null) {
112 throw new NullPointerException("ELContext -> null");
113 }
114 boolean result = false;
115 FacesContext facesContext = (FacesContext)
116 context.getContext(FacesContext.class);
117 assert(null != facesContext);
118 try {
119 result = binding.isReadOnly(facesContext);
120 }
121 catch (Throwable e) {
122 throw new ELException(e);
123 }
124 return result;
125 }
126
127 public Class<?> getType(ELContext context) throws ELException {
128 assert(null != binding);
129 if (context == null) {
130 throw new NullPointerException("ELContext -> null");
131 }
132 Class result = null;
133 FacesContext facesContext = (FacesContext)
134 context.getContext(FacesContext.class);
135 assert(null != facesContext);
136 try {
137 result = binding.getType(facesContext);
138 }
139 catch (Throwable e) {
140 throw new ELException(e);
141 }
142 return result;
143 }
144
145 /**
146 * <p>Always return <code>false</code> since we can't possibly know
147 * if this is a literal text binding or not.</p>
148 */
149
150 public boolean isLiteralText() {
151 return false;
152 }
153
154 public Class<?> getExpectedType() {
155 assert(null != binding);
156 Class result = null;
157 FacesContext context = FacesContext.getCurrentInstance();
158 try {
159 Object value = binding.getValue(context);
160 result = value.getClass();
161 }
162 catch (Throwable e) {
163 result = null;
164 }
165 return result;
166 }
167
168 public String getExpressionString() {
169 assert(null != binding);
170 return binding.getExpressionString();
171
172 }
173
174 public boolean equals(Object other) {
175
176 if (other == this) {
177 return true;
178 }
179
180 if (other instanceof ValueExpressionValueBindingAdapter) {
181 ValueBinding vb =
182 ((ValueExpressionValueBindingAdapter) other).getWrapped();
183 return (binding.equals(vb));
184 } else if (other instanceof ValueExpression) {
185 FacesContext context = FacesContext.getCurrentInstance();
186 ValueExpression otherVE = (ValueExpression) other;
187 Class type = binding.getType(context);
188 if (type != null) {
189 return type.equals(otherVE.getType(context.getELContext()));
190 }
191 }
192 return false;
193
194 }
195
196 public int hashCode() {
197 assert(null != binding);
198
199 return binding.hashCode();
200 }
201
202 public String getDelimiterSyntax() {
203 // PENDING (visvan) Implementation
204 return "";
205 }
206
207 //
208 // Methods from StateHolder
209 //
210
211
212
213 public Object saveState(FacesContext context) {
214 if (context == null) {
215 throw new NullPointerException();
216 }
217 Object result = null;
218 if (!tranzient) {
219 if (binding instanceof StateHolder) {
220 Object [] stateStruct = new Object[2];
221
222 // save the actual state of our wrapped binding
223 stateStruct[0] = ((StateHolder)binding).saveState(context);
224 // save the class name of the binding impl
225 stateStruct[1] = binding.getClass().getName();
226
227 result = stateStruct;
228 }
229 else {
230 result = binding;
231 }
232 }
233
234 return result;
235 }
236
237 public void restoreState(FacesContext context, Object state) {
238 if (context == null) {
239 throw new NullPointerException();
240 }
241 // if we have state
242 if (null == state) {
243 return;
244 }
245
246 if (!(state instanceof ValueBinding)) {
247 Object [] stateStruct = (Object []) state;
248 Object savedState = stateStruct[0];
249 String className = stateStruct[1].toString();
250 ValueBinding result = null;
251
252 Class toRestoreClass = null;
253 if (null != className) {
254 try {
255 toRestoreClass = loadClass(className, this);
256 }
257 catch (ClassNotFoundException e) {
258 throw new IllegalStateException(e.getMessage());
259 }
260
261 if (null != toRestoreClass) {
262 try {
263 result =
264 (ValueBinding) toRestoreClass.newInstance();
265 }
266 catch (InstantiationException e) {
267 throw new IllegalStateException(e.getMessage());
268 }
269 catch (IllegalAccessException a) {
270 throw new IllegalStateException(a.getMessage());
271 }
272 }
273
274 if (null != result && null != savedState) {
275 // don't need to check transient, since that was
276 // done on the saving side.
277 ((StateHolder)result).restoreState(context, savedState);
278 }
279 binding = result;
280 }
281 }
282 else {
283 binding = (ValueBinding) state;
284 }
285 }
286
287 private boolean tranzient = false;
288
289 public boolean isTransient() {
290 return tranzient;
291 }
292
293 public void setTransient(boolean newTransientValue) {
294 tranzient = newTransientValue;
295 }
296
297 //
298 // Helper methods for StateHolder
299 //
300
301 private static Class loadClass(String name,
302 Object fallbackClass) throws ClassNotFoundException {
303 ClassLoader loader =
304 Thread.currentThread().getContextClassLoader();
305 if (loader == null) {
306 loader = fallbackClass.getClass().getClassLoader();
307 }
308 return Class.forName(name, true, loader);
309 }
310
311
312 //
313 // methods used by classes aware of this class's wrapper nature
314 //
315
316 public ValueBinding getWrapped() {
317 return binding;
318 }
319
320 }