base/runtime/org.argeo.eclipse.ui/src/main/java/org/argeo/eclipse/spring/SpringExtensionFactory.java

   1 /*
   2  * Copyright (C) 2007-2012 Argeo GmbH
   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.argeo.eclipse.spring;
  17
  18 import org.argeo.ArgeoException;
  19 import org.eclipse.core.runtime.CoreException;
  20 import org.eclipse.core.runtime.IConfigurationElement;
  21 import org.eclipse.core.runtime.IExecutableExtension;
  22 import org.eclipse.core.runtime.IExecutableExtensionFactory;
  23 import org.eclipse.core.runtime.IExtension;
  24 import org.springframework.context.ApplicationContext;
  25
  26 /**
  27  * The Spring Extension Factory builds a bridge between the Eclipse Extension
  28  * Registry and the Spring Framework (especially Spring Dynamic Modules).
  29  *
  30  * It allows you to define your extension as a spring bean within the spring
  31  * application context of your bundle. If you would like to use this bean as an
  32  * instance of an extension (an Eclipse RCP view, for example) you define the
  33  * extension with this spring extension factory as the class to be created.
  34  *
  35  * To let the spring extension factory pick the right bean from your application
  36  * context you need to set the bean id to the same value as the id of the view
  37  * within the view definition, for example. This is important if your extension
  38  * definition contains more than one element, where each element has its own id.
  39  *
  40  * If the extension definition elements themselves have no id attribute the
  41  * spring extension factory uses the id of the extension itself to identify the
  42  * bean.
  43  *
  44  * original code from: <a href=
  45  * "http://martinlippert.blogspot.com/2008/10/new-version-of-spring-extension-factory.html"
  46  * >Blog entry</a>
  47  *
  48  * @author Martin Lippert
  49  * @author mbaudier
  50  */
  51 public class SpringExtensionFactory implements IExecutableExtensionFactory,
  52                 IExecutableExtension {
  53
  54         private Object bean;
  55
  56         public Object create() throws CoreException {
  57                 if (bean == null)
  58                         throw new ArgeoException("No underlying bean for extension");
  59                 return bean;
  60         }
  61
  62         public void setInitializationData(IConfigurationElement config,
  63                         String propertyName, Object data) throws CoreException {
  64                 String bundleSymbolicName = config.getContributor().getName();
  65                 ApplicationContext applicationContext = ApplicationContextTracker
  66                                 .getApplicationContext(bundleSymbolicName);
  67                 if (applicationContext == null)
  68                         throw new ArgeoException(
  69                                         "Cannot find application context for bundle "
  70                                                         + bundleSymbolicName);
  71
  72                 String beanName = getBeanName(data, config);
  73                 if (beanName == null)
  74                         throw new ArgeoException("Cannot find bean name for extension "
  75                                         + config);
  76
  77                 if (!applicationContext.containsBean(beanName)) {
  78                         if (beanName.startsWith(bundleSymbolicName))
  79                                 beanName = beanName.substring(bundleSymbolicName.length() + 1);
  80                 }
  81
  82                 if (!applicationContext.containsBean(beanName))
  83                         throw new ArgeoException("No bean with name '" + beanName + "'");
  84
  85                 this.bean = applicationContext.getBean(beanName);
  86                 if (this.bean instanceof IExecutableExtension) {
  87                         ((IExecutableExtension) this.bean).setInitializationData(config,
  88                                         propertyName, data);
  89                 }
  90         }
  91
  92         private String getBeanName(Object data, IConfigurationElement config) {
  93
  94                 // try the specific bean id the extension defines
  95                 if (data != null && data.toString().length() > 0) {
  96                         return data.toString();
  97                 }
  98
  99                 // try the id of the config element
 100                 if (config.getAttribute("id") != null) {
 101                         return config.getAttribute("id");
 102                 }
 103
 104                 // try the id of the extension element itself
 105                 if (config.getParent() != null
 106                                 && config.getParent() instanceof IExtension) {
 107                         IExtension extensionDefinition = (IExtension) config.getParent();
 108                         return extensionDefinition.getSimpleIdentifier();
 109                 }
 110
 111                 return null;
 112         }
 113
 114 }