eclipse/plugins/org.argeo.eclipse.ui/src/main/java/org/argeo/eclipse/spring/SpringExtensionFactory.java

   1 /*
   2  * Copyright (C) 2010 Mathieu Baudier <mbaudier@argeo.org>
   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
  17 package org.argeo.eclipse.spring;
  18
  19 import org.argeo.ArgeoException;
  20 import org.eclipse.core.runtime.CoreException;
  21 import org.eclipse.core.runtime.IConfigurationElement;
  22 import org.eclipse.core.runtime.IExecutableExtension;
  23 import org.eclipse.core.runtime.IExecutableExtensionFactory;
  24 import org.eclipse.core.runtime.IExtension;
  25 import org.springframework.context.ApplicationContext;
  26
  27 /**
  28  * The Spring Extension Factory builds a bridge between the Eclipse Extension
  29  * Registry and the Spring Framework (especially Spring Dynamic Modules).
  30  *
  31  * It allows you to define your extension as a spring bean within the spring
  32  * application context of your bundle. If you would like to use this bean as an
  33  * instance of an extension (an Eclipse RCP view, for example) you define the
  34  * extension with this spring extension factory as the class to be created.
  35  *
  36  * To let the spring extension factory pick the right bean from your application
  37  * context you need to set the bean id to the same value as the id of the view
  38  * within the view definition, for example. This is important if your extension
  39  * definition contains more than one element, where each element has its own id.
  40  *
  41  * If the extension definition elements themselves have no id attribute the
  42  * spring extension factory uses the id of the extension itself to identify the
  43  * bean.
  44  *
  45  * original code from: <a href=
  46  * "http://martinlippert.blogspot.com/2008/10/new-version-of-spring-extension-factory.html"
  47  * >Blog entry</a>
  48  *
  49  * @author Martin Lippert
  50  * @author mbaudier
  51  */
  52 public class SpringExtensionFactory implements IExecutableExtensionFactory,
  53                 IExecutableExtension {
  54
  55         private Object bean;
  56
  57         public Object create() throws CoreException {
  58                 if (bean == null)
  59                         throw new ArgeoException("No underlying bean for extension");
  60                 return bean;
  61         }
  62
  63         public void setInitializationData(IConfigurationElement config,
  64                         String propertyName, Object data) throws CoreException {
  65                 String beanName = getBeanName(data, config);
  66                 if (beanName == null)
  67                         throw new ArgeoException("Cannot find bean name for extension "
  68                                         + config);
  69
  70                 String bundleSymbolicName = config.getContributor().getName();
  71                 ApplicationContext appContext = ApplicationContextTracker
  72                                 .getApplicationContext(bundleSymbolicName);
  73                 if (appContext == null)
  74                         throw new ArgeoException(
  75                                         "Cannot find application context for bundle "
  76                                                         + bundleSymbolicName);
  77
  78                 this.bean = appContext.getBean(beanName);
  79                 if (this.bean instanceof IExecutableExtension) {
  80                         ((IExecutableExtension) this.bean).setInitializationData(config,
  81                                         propertyName, data);
  82                 }
  83         }
  84
  85         private String getBeanName(Object data, IConfigurationElement config) {
  86
  87                 // try the specific bean id the extension defines
  88                 if (data != null && data.toString().length() > 0) {
  89                         return data.toString();
  90                 }
  91
  92                 // try the id of the config element
  93                 if (config.getAttribute("id") != null) {
  94                         return config.getAttribute("id");
  95                 }
  96
  97                 // try the id of the extension element itself
  98                 if (config.getParent() != null
  99                                 && config.getParent() instanceof IExtension) {
 100                         IExtension extensionDefinition = (IExtension) config.getParent();
 101                         return extensionDefinition.getSimpleIdentifier();
 102                 }
 103
 104                 return null;
 105         }
 106
 107 }