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Java > Open Source Codes > org > directwebremoting > guice > InternalConverterManager


1 /*
2  * Copyright 2007 Tim Peierls
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  * http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 package org.directwebremoting.guice;
17
18 import com.google.inject.Key;
19 import com.google.inject.Injector;
20 import com.google.inject.Provider;
21
22 import java.util.Collection JavaDoc;
23 import java.util.Map JavaDoc;
24
25 import org.directwebremoting.dwrp.DefaultConverterManager;
26 import org.directwebremoting.extend.*;
27 import org.directwebremoting.util.Logger;
28
29 import static org.directwebremoting.guice.DwrGuiceUtil.getInjector;
30 import static org.directwebremoting.guice.DwrGuiceUtil.getServletContext;
31
32 /**
33  * Extends an existing converter manager with an injected list of converters
34  * specified at Guice bind-time. Only to be used in conjection with
35  * {@link DwrGuiceServlet}.
36  * @author Tim Peierls [tim at peierls dot net]
37  */
38 public class InternalConverterManager implements ConverterManager
39 {
40     /**
41      * Retrieves an underlying converter manager from thread-local state
42      * to which this class delegates {@link ConverterManager} calls.
43      */
44     public InternalConverterManager()
45     {
46         this.converterManager = getConverterManager();
47         addConverters();
48     }
49
50
51     public void addConverterType(String JavaDoc id, String JavaDoc className)
52     {
53         converterManager.addConverterType(id, className);
54     }
55
56     public void addConverter(String JavaDoc match, String JavaDoc type, Map JavaDoc params) throws IllegalArgumentException JavaDoc, InstantiationException JavaDoc, IllegalAccessException JavaDoc
57     {
58         converterManager.addConverter(match, type, params);
59     }
60
61     public void addConverter(String JavaDoc match, Converter converter) throws IllegalArgumentException JavaDoc
62     {
63         converterManager.addConverter(match, converter);
64     }
65
66     public Collection JavaDoc getConverterMatchStrings()
67     {
68         return converterManager.getConverterMatchStrings();
69     }
70
71     public Converter getConverterByMatchString(String JavaDoc match)
72     {
73         return converterManager.getConverterByMatchString(match);
74     }
75
76     public boolean isConvertable(Class JavaDoc paramType)
77     {
78         return converterManager.isConvertable(paramType);
79     }
80
81     public Object JavaDoc convertInbound(Class JavaDoc paramType, InboundVariable iv, InboundContext inctx, TypeHintContext incc) throws MarshallException
82     {
83         return converterManager.convertInbound(paramType, iv, inctx, incc);
84     }
85
86     public OutboundVariable convertOutbound(Object JavaDoc object, OutboundContext outctx) throws MarshallException
87     {
88         return converterManager.convertOutbound(object, outctx);
89     }
90
91     public void setExtraTypeInfo(TypeHintContext thc, Class JavaDoc type)
92     {
93         converterManager.setExtraTypeInfo(thc, type);
94     }
95
96     public Class JavaDoc getExtraTypeInfo(TypeHintContext thc)
97     {
98         return converterManager.getExtraTypeInfo(thc);
99     }
100
101     public void setConverters(Map JavaDoc converters)
102     {
103         converterManager.setConverters(converters);
104     }
105
106     
107     private final ConverterManager converterManager;
108
109     private void addConverters()
110     {
111         Injector injector = getInjector();
112         for (Key<?> key : injector.getBindings().keySet())
113         {
114             Class JavaDoc<?> atype = key.getAnnotationType();
115             if (atype != null && Converting.class.isAssignableFrom(atype))
116             {
117                 Converting ann = Converting.class.cast(key.getAnnotation());
118                 
119                 String JavaDoc match = ann.match();
120                 Class JavaDoc type = ann.type();
121                 Class JavaDoc impl = ann.impl();
122                 
123                 if ("".equals(match))
124                 {
125                     // Use the type name as a match string
126 match = type.getName();
127                 }
128
129                 Provider<Converter> provider = null;
130                 Class JavaDoc cvtType;
131                 
132                 if (impl.equals(Void JavaDoc.class))
133                 {
134                     // No impl specified, so there should be a Converter
135 // for this key.
136
137                     provider = injector.getProvider((Key<Converter>) key);
138                     cvtType = type;
139                 }
140                 else
141                 {
142                     // Impl class specified, so the Converter for key is
143 // bogus (the injected constructor InternalConverter
144 // is just to keep Guice happy); see the two-arg
145 // bindConversion method in AbstractDwrModule.
146
147                     try
148                     {
149                         // First try looking for a Converter for impl in the bindings.
150
151                         Key<Converter> ikey = Key.get(Converter.class, new ConvertingImpl(impl));
152                         provider = injector.getProvider(ikey);
153                     }
154                     catch (RuntimeException JavaDoc e)
155                     {
156                         // Ignore any trouble we have looking things up.
157 }
158                     
159                     if (provider == null)
160                     {
161                         // It wasn't in the bindings, so use a Provider that
162 // looks in the underlying ConverterManager.
163
164                         final String JavaDoc implMatch = impl.getName();
165                         provider = new Provider<Converter>()
166                         {
167                             public Converter get()
168                             {
169                                 return getConverterByMatchString(implMatch);
170                             }
171                         };
172                     }
173                     
174                     cvtType = impl;
175                 }
176                 addConverter(match, new InternalConverter(cvtType, provider));
177             }
178         }
179     }
180     
181     /**
182      * Stores a type name in a thread-local variable for later retrieval by
183      * {@code getConverterManager}.
184      */
185     static void setTypeName(String JavaDoc name)
186     {
187         typeName.set(name);
188     }
189     
190     private static ConverterManager getConverterManager()
191     {
192         String JavaDoc name = typeName.get();
193         try
194         {
195             Class JavaDoc<? extends ConverterManager> cls =
196                 (Class JavaDoc<? extends ConverterManager>) Class.forName(name);
197             return cls.newInstance();
198         }
199         catch (Exception JavaDoc e)
200         {
201             if (name != null && !"".equals(name)) {
202                 log.warn("Couldn't make ConverterManager from type: " + name);
203             }
204             return new DefaultConverterManager();
205         }
206     }
207
208
209     /**
210      * Place to stash a type name for retrieval in same thread.
211      */
212     private static final ThreadLocal JavaDoc<String JavaDoc> typeName = new ThreadLocal JavaDoc<String JavaDoc>();
213
214
215     /**
216      * The log stream
217      */
218     private static final Logger log = Logger.getLogger(InternalConverterManager.class);
219 }
220
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