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1 /*
2 * Copyright (c) 2003 The Visigoth Software Society. All rights
3 * reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 *
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 *
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in
14 * the documentation and/or other materials provided with the
15 * distribution.
16 *
17 * 3. The end-user documentation included with the redistribution, if
18 * any, must include the following acknowledgement:
19 * "This product includes software developed by the
20 * Visigoth Software Society (http://www.visigoths.org/)."
21 * Alternately, this acknowledgement may appear in the software itself,
22 * if and wherever such third-party acknowledgements normally appear.
23 *
24 * 4. Neither the name "FreeMarker", "Visigoth", nor any of the names of the
25 * project contributors may be used to endorse or promote products derived
26 * from this software without prior written permission. For written
27 * permission, please contact visigoths@visigoths.org.
28 *
29 * 5. Products derived from this software may not be called "FreeMarker" or "Visigoth"
30 * nor may "FreeMarker" or "Visigoth" appear in their names
31 * without prior written permission of the Visigoth Software Society.
32 *
33 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
34 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
35 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
36 * DISCLAIMED. IN NO EVENT SHALL THE VISIGOTH SOFTWARE SOCIETY OR
37 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
38 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
39 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
40 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
41 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
42 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
43 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
44 * SUCH DAMAGE.
45 * ====================================================================
46 *
47 * This software consists of voluntary contributions made by many
48 * individuals on behalf of the Visigoth Software Society. For more
49 * information on the Visigoth Software Society, please see
50 * http://www.visigoths.org/
51 */
52
53 package freemarker.ext.beans;
54
55 import java.beans.IndexedPropertyDescriptor;
56 import java.beans.PropertyDescriptor;
57 import java.lang.reflect.Field;
58 import java.lang.reflect.InvocationTargetException;
59 import java.lang.reflect.Method;
60 import java.util.ArrayList;
61 import java.util.Collection;
62 import java.util.HashMap;
63 import java.util.List;
64 import java.util.Map;
65 import java.util.Set;
66
67 import freemarker.core.CollectionAndSequence;
68 import freemarker.ext.util.ModelFactory;
69 import freemarker.ext.util.WrapperTemplateModel;
70 import freemarker.log.Logger;
71 import freemarker.template.AdapterTemplateModel;
72 import freemarker.template.ObjectWrapper;
73 import freemarker.template.SimpleScalar;
74 import freemarker.template.SimpleSequence;
75 import freemarker.template.TemplateCollectionModel;
76 import freemarker.template.TemplateHashModelEx;
77 import freemarker.template.TemplateModel;
78 import freemarker.template.TemplateModelException;
79 import freemarker.template.TemplateModelIterator;
80 import freemarker.template.TemplateScalarModel;
81
82 /**
83 * A class that will wrap an arbitrary object into {@link freemarker.template.TemplateHashModel}
84 * interface allowing calls to arbitrary property getters and invocation of
85 * accessible methods on the object from a template using the
86 * <tt>object.foo</tt> to access properties and <tt>object.bar(arg1, arg2)</tt> to
87 * invoke methods on it. You can also use the <tt>object.foo[index]</tt> syntax to
88 * access indexed properties. It uses Beans {@link java.beans.Introspector}
89 * to dynamically discover the properties and methods.
90 * @author Attila Szegedi
91 * @version $Id: BeanModel.java,v 1.49.2.4 2006/11/12 10:20:37 szegedia Exp $
92 */
93
94 public class BeanModel
95 implements
96 TemplateHashModelEx, AdapterTemplateModel, WrapperTemplateModel
97 {
98 private static final Logger logger = Logger.getLogger("freemarker.beans");
99 protected final Object object;
100 protected final BeansWrapper wrapper;
101
102 // We use this to represent an unknown value as opposed to known value of null (JR)
103 private static final TemplateModel UNKNOWN = new SimpleScalar("UNKNOWN");
104
105 static final ModelFactory FACTORY =
106 new ModelFactory()
107 {
108 public TemplateModel create(Object object, ObjectWrapper wrapper)
109 {
110 return new BeanModel(object, (BeansWrapper)wrapper);
111 }
112 };
113
114 // Cached template models that implement member properties and methods for this
115 // instance. Keys are FeatureDescriptor instances (from classCache values),
116 // values are either ReflectionMethodModels/ReflectionScalarModels
117 private HashMap memberMap;
118
119 /**
120 * Creates a new model that wraps the specified object. Note that there are
121 * specialized subclasses of this class for wrapping arrays, collections,
122 * enumeration, iterators, and maps. Note also that the superclass can be
123 * used to wrap String objects if only scalar functionality is needed. You
124 * can also choose to delegate the choice over which model class is used for
125 * wrapping to {@link BeansWrapper#wrap(Object)}.
126 * @param object the object to wrap into a model.
127 * @param wrapper the {@link BeansWrapper} associated with this model.
128 * Every model has to have an associated {@link BeansWrapper} instance. The
129 * model gains many attributes from its wrapper, including the caching
130 * behavior, method exposure level, method-over-item shadowing policy etc.
131 */
132 public BeanModel(Object object, BeansWrapper wrapper)
133 {
134 this.object = object;
135 this.wrapper = wrapper;
136 if (object == null) {
137 return;
138 }
139 wrapper.introspectClass(object.getClass());
140 }
141
142 /**
143 * Uses Beans introspection to locate a property or method with name
144 * matching the key name. If a method or property is found, it is wrapped
145 * into {@link freemarker.template.TemplateMethodModelEx} (for a method or
146 * indexed property), or evaluated on-the-fly and the return value wrapped
147 * into appropriate model (for a simple property) Models for various
148 * properties and methods are cached on a per-class basis, so the costly
149 * introspection is performed only once per property or method of a class.
150 * (Side-note: this also implies that any class whose method has been called
151 * will be strongly referred to by the framework and will not become
152 * unloadable until this class has been unloaded first. Normally this is not
153 * an issue, but can be in a rare scenario where you create many classes on-
154 * the-fly. Also, as the cache grows with new classes and methods introduced
155 * to the framework, it may appear as if it were leaking memory. The
156 * framework does, however detect class reloads (if you happen to be in an
157 * environment that does this kind of things--servlet containers do it when
158 * they reload a web application) and flushes the cache. If no method or
159 * property matching the key is found, the framework will try to invoke
160 * methods with signature
161 * <tt>non-void-return-type get(java.lang.String)</tt>,
162 * then <tt>non-void-return-type get(java.lang.Object)</tt>, or
163 * alternatively (if the wrapped object is a resource bundle)
164 * <tt>Object getObject(java.lang.String)</tt>.
165 * @throws TemplateModelException if there was no property nor method nor
166 * a generic <tt>get</tt> method to invoke.
167 */
168 public TemplateModel get(String key)
169 throws
170 TemplateModelException
171 {
172 Class clazz = object.getClass();
173 Map classInfo = wrapper.getClassKeyMap(clazz);
174 TemplateModel retval = null;
175
176 try
177 {
178 if(wrapper.isMethodsShadowItems())
179 {
180 Object fd = classInfo.get(key);
181 if(fd != null)
182 {
183 retval = invokeThroughDescriptor(fd, classInfo);
184 } else {
185 retval = invokeGenericGet(classInfo, clazz, key);
186 }
187 }
188 else
189 {
190 TemplateModel model = invokeGenericGet(classInfo, clazz, key);
191 final TemplateModel nullModel = wrapper.wrap(null);
192 if(model != nullModel && model != UNKNOWN)
193 {
194 return model;
195 }
196 Object fd = classInfo.get(key);
197 if(fd != null) {
198 retval = invokeThroughDescriptor(fd, classInfo);
199 if (retval == UNKNOWN && model == nullModel) {
200 // This is the (somewhat subtle) case where the generic get() returns null
201 // and we have no bean info, so we respect the fact that
202 // the generic get() returns null and return null. (JR)
203 retval = nullModel;
204 }
205 }
206 }
207 if (retval == UNKNOWN) {
208 if (wrapper.isStrict()) {
209 throw new InvalidPropertyException("No such bean property: " + key);
210 } else if (logger.isDebugEnabled()) {
211 logNoSuchKey(key, classInfo);
212 }
213 retval = wrapper.wrap(null);
214 }
215 return retval;
216 }
217 catch(TemplateModelException e)
218 {
219 throw e;
220 }
221 catch(Exception e)
222 {
223 throw new TemplateModelException("get(" + key + ") failed on " +
224 "instance of " + object.getClass().getName(), e);
225 }
226 }
227
228 private void logNoSuchKey(String key, Map keyMap)
229 {
230 logger.debug("Key '" + key + "' was not found on instance of " +
231 object.getClass().getName() + ". Introspection information for " +
232 "the class is: " + keyMap);
233 }
234
235 /**
236 * Whether the model has a plain get(String) or get(Object) method
237 */
238
239 protected boolean hasPlainGetMethod() {
240 return wrapper.getClassKeyMap(object.getClass()).get(BeansWrapper.GENERIC_GET_KEY) != null;
241 }
242
243 private TemplateModel invokeThroughDescriptor(Object desc, Map classInfo)
244 throws
245 IllegalAccessException,
246 InvocationTargetException,
247 TemplateModelException
248 {
249 // See if this particular instance has a cached implementation
250 // for the requested feature descriptor
251 TemplateModel member;
252 synchronized(this) {
253 if(memberMap != null) {
254 member = (TemplateModel)memberMap.get(desc);
255 }
256 else {
257 member = null;
258 }
259 }
260
261 if(member != null)
262 return member;
263
264 TemplateModel retval = UNKNOWN;
265 if(desc instanceof IndexedPropertyDescriptor)
266 {
267 Method readMethod =
268 ((IndexedPropertyDescriptor)desc).getIndexedReadMethod();
269 retval = member =
270 new SimpleMethodModel(object, readMethod,
271 BeansWrapper.getArgTypes(classInfo, readMethod), wrapper);
272 }
273 else if(desc instanceof PropertyDescriptor)
274 {
275 PropertyDescriptor pd = (PropertyDescriptor)desc;
276 retval = wrapper.invokeMethod(object, pd.getReadMethod(), null);
277 // (member == null) condition remains, as we don't cache these
278 }
279 else if(desc instanceof Field)
280 {
281 retval = wrapper.wrap(((Field)desc).get(object));
282 // (member == null) condition remains, as we don't cache these
283 }
284 else if(desc instanceof Method)
285 {
286 Method method = (Method)desc;
287 retval = member = new SimpleMethodModel(object, method,
288 BeansWrapper.getArgTypes(classInfo, method), wrapper);
289 }
290 else if(desc instanceof MethodMap)
291 {
292 retval = member =
293 new OverloadedMethodModel(object, (MethodMap)desc);
294 }
295
296 // If new cacheable member was created, cache it
297 if(member != null) {
298 synchronized(this) {
299 if(memberMap == null) {
300 memberMap = new HashMap();
301 }
302 memberMap.put(desc, member);
303 }
304 }
305 return retval;
306 }
307
308 protected TemplateModel invokeGenericGet(Map keyMap, Class clazz, String key)
309 throws
310 IllegalAccessException,
311 InvocationTargetException,
312 TemplateModelException
313 {
314 Method genericGet = (Method)keyMap.get(BeansWrapper.GENERIC_GET_KEY);
315 if(genericGet == null)
316 return UNKNOWN;
317
318 return wrapper.invokeMethod(object, genericGet, new Object[] { key });
319 }
320
321 protected TemplateModel wrap(Object obj)
322 throws TemplateModelException
323 {
324 return wrapper.getOuterIdentity().wrap(obj);
325 }
326
327 protected Object unwrap(TemplateModel model)
328 throws
329 TemplateModelException
330 {
331 return wrapper.unwrap(model);
332 }
333
334 /**
335 * Tells whether the model is empty. It is empty if either the wrapped
336 * object is null, or it is a Boolean with false value.
337 */
338 public boolean isEmpty()
339 {
340 if (object instanceof String) {
341 return ((String) object).length() == 0;
342 }
343 if (object instanceof Collection) {
344 return ((Collection) object).isEmpty();
345 }
346 if (object instanceof Map) {
347 return ((Map) object).isEmpty();
348 }
349 return object == null || Boolean.FALSE.equals(object);
350 }
351
352 public Object getAdaptedObject(Class hint) {
353 return object;
354 }
355
356 public Object getWrappedObject() {
357 return object;
358 }
359
360 public int size()
361 {
362 return wrapper.keyCount(object.getClass());
363 }
364
365 public TemplateCollectionModel keys()
366 {
367 return new CollectionAndSequence(new SimpleSequence(keySet(), wrapper));
368 }
369
370 public TemplateCollectionModel values() throws TemplateModelException
371 {
372 List values = new ArrayList(size());
373 TemplateModelIterator it = keys().iterator();
374 while (it.hasNext()) {
375 String key = ((TemplateScalarModel)it.next()).getAsString();
376 values.add(get(key));
377 }
378 return new CollectionAndSequence(new SimpleSequence(values, wrapper));
379 }
380
381 public String toString() {
382 return object.toString();
383 }
384
385 /**
386 * Helper method to support TemplateHashModelEx. Returns the Set of
387 * Strings which are available via the TemplateHashModel
388 * interface. Subclasses that override <tt>invokeGenericGet</tt> to
389 * provide additional hash keys should also override this method.
390 */
391 protected Set keySet()
392 {
393 return wrapper.keySet(object.getClass());
394 }
395 }