wamblee.org Git - utils/blob - system/spring/src/main/java/org/wamblee/system/spring/SpringComponent.java

   1 /*
   2  * Copyright 2007 the original author or authors.
   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.wamblee.system.spring;
  17
  18 import java.util.Map;
  19 import java.util.Properties;
  20
  21 import org.springframework.beans.MutablePropertyValues;
  22 import org.springframework.beans.factory.config.BeanDefinition;
  23 import org.springframework.beans.factory.config.ConstructorArgumentValues;
  24 import org.springframework.beans.factory.support.RootBeanDefinition;
  25 import org.springframework.context.support.AbstractApplicationContext;
  26 import org.springframework.context.support.ClassPathXmlApplicationContext;
  27 import org.springframework.context.support.GenericApplicationContext;
  28 import org.wamblee.system.core.AbstractComponent;
  29 import org.wamblee.system.core.ProvidedInterface;
  30 import org.wamblee.system.core.RequiredInterface;
  31 import org.wamblee.system.core.SystemAssemblyException;
  32
  33 /**
  34  * Represents a system configured based on spring. The spring config files that
  35  * are configured should not contain any PropertyPlaceholderConfigurer objects.
  36  *
  37  * @author Erik Brakkee
  38  */
  39 public class SpringComponent extends AbstractComponent {
  40
  41         static final ThreadLocal<SpringComponent> THIS = new ThreadLocal<SpringComponent>();
  42
  43         private Properties _properties;
  44         private String[] _configFiles;
  45         private Map<String, ProvidedInterface> _provided;
  46         private Map<RequiredInterface, String> _required;
  47         /**
  48          * Parent application context containing required services.
  49          */
  50         private GenericApplicationContext _parentContext;
  51
  52         /**
  53          * Application context containing parsed objects.
  54          */
  55         private AbstractApplicationContext _context;
  56
  57         /**
  58          * Constructs a spring system.
  59          *
  60          * @param aName
  61          *            Name of the system.
  62          * @param aConfigFil
  63          *            Spring config files to read.
  64          * @param aProvided
  65          *            Map of bean name to service descriptor describing the bean
  66          *            names that the spring config files use for each required
  67          *            service.
  68          * @param aRequired
  69          *            Map of bean name to service descriptor describing the bean
  70          *            names that the spring config files use for each required
  71          *            service.
  72          */
  73         public SpringComponent(String aName, String[] aConfigFiles,
  74                         Map<String, ProvidedInterface> aProvided,
  75                         Map<RequiredInterface, String> aRequired) {
  76                 super(aName, aProvided.values().toArray(new ProvidedInterface[0]),
  77                                 aRequired.keySet().toArray(new RequiredInterface[0]));
  78                 _properties = new Properties();
  79                 _configFiles = aConfigFiles;
  80                 _provided = aProvided;
  81                 _required = aRequired;
  82         }
  83
  84         /**
  85          * Must be called to make a property available in the application context.
  86          *
  87          * @param aKey
  88          *            Property key.
  89          * @param aValue
  90          *            Property value.
  91          */
  92         public void setProperty(String aKey, String aValue) {
  93                 _properties.put(aKey, aValue);
  94         }
  95
  96         public void addProperties(Properties aProperties) {
  97                 for (Object key : aProperties.keySet()) {
  98                         setProperty((String) key, aProperties.getProperty((String) key));
  99                 }
 100         }
 101
 102         @Override
 103         protected void doStart() {
 104
 105                 SpringComponent old = THIS.get();
 106                 THIS.set(this);
 107                 try {
 108                         _parentContext = new GenericApplicationContext();
 109
 110                         registerRequiredServices();
 111
 112                         _parentContext.refresh();
 113
 114                         parseConfigFiles();
 115
 116                         _context
 117                                         .addBeanFactoryPostProcessor(new PropertySetter(_properties));
 118                         _context.refresh();
 119
 120                         exposeProvidedServices();
 121                 } catch (Exception e) {
 122                         throw new SystemAssemblyException(
 123                                         "Failed to assemble spring system", e);
 124                 } finally {
 125                         THIS.set(old);
 126                 }
 127         }
 128
 129         private void exposeProvidedServices() {
 130                 // Call addService for each provided service.
 131
 132                 for (String name : _provided.keySet()) {
 133                         Object svc = _context.getBean(name);
 134                         if (svc == null) {
 135                                 throw new IllegalArgumentException(getQualifiedName() + ": service '"
 136                                                 + name + "' is null");
 137                         }
 138                         addService(_provided.get(name), svc);
 139                 }
 140         }
 141
 142         private void parseConfigFiles() {
 143                 // Parse spring config files
 144
 145                 _context = new ClassPathXmlApplicationContext((String[]) _configFiles,
 146                                 _parentContext);
 147         }
 148
 149         private void registerRequiredServices() {
 150                 // Register required services in a parent context
 151                 for (RequiredInterface required: getRequiredServices()) {
 152                         String beanName = _required.get(required);
 153                         ConstructorArgumentValues cargs = new ConstructorArgumentValues();
 154                         cargs.addGenericArgumentValue(required.getName());
 155                         BeanDefinition definition = new RootBeanDefinition(
 156                                         RequiredServiceBean.class, cargs,
 157                                         new MutablePropertyValues());
 158                         _parentContext.registerBeanDefinition(beanName, definition);
 159                 }
 160         }
 161
 162         @Override
 163         protected void doStop() {
 164                 _context.close();
 165         }
 166 }