| /* Copyright 2004 The Apache Software Foundation |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| package org.apache.xmlbeans.impl.schema; |
| |
| import org.apache.xmlbeans.SchemaTypeSystem; |
| |
| /** |
| * This class is the hook which causes the SchemaTypeSystem to be loaded when |
| * a generated class is used. It isn't used by the runtime directly, instead |
| * this class is used by the schema compiler as a template class. By using a |
| * template class, the SchemaTypeSystemImpl can create all the binary files |
| * required without needing to rely on javac. The generated source still |
| * requires a java compiler. |
| * |
| * @see SchemaTypeSystemImpl#save(org.apache.xmlbeans.Filer) |
| */ |
| // |
| // !!! It's important that there never NEVER be any references to this class because |
| // !!! the static initializer will fail. This class must only be used as a class file. |
| // !!! If this scares you, turn back now !!! |
| // |
| // !!! If you modify this class, you will have to run bootstrap. |
| // !!! If this scares you, turn back now !!! |
| // |
| public class TypeSystemHolder |
| { |
| private TypeSystemHolder() { } |
| |
| public static final SchemaTypeSystem typeSystem = loadTypeSystem(); |
| |
| // Commenting out this line has the effect of not loading all components in a |
| // typesystem upfront, but just as they are needed, which may improve |
| // performance significantly |
| //static { typeSystem.resolve(); } |
| |
| private static final SchemaTypeSystem loadTypeSystem() |
| { |
| try |
| { |
| // The fact that we are using TypeSystemHolder.class.getClassLoader() |
| // to load the SchemaTypeSystem class means that the TypeSystemHolder's |
| // classloader MUST be a descendant of the XmlBeans classloader, even |
| // though it can be different. |
| // In other words, each Schema type has only one copy per VM, not one |
| // copy per copy of XmlBeans in use, therefore this implies that |
| // there either must be one copy of XmlBeans in the VM or copies in |
| // different classloaders will each need a different copy of one |
| // Schema type, which seems a reasonable restriction, but needs to be |
| // understood nevertheless |
| return (SchemaTypeSystem) |
| Class.forName( |
| "org.apache.xmlbeans.impl.schema.SchemaTypeSystemImpl", |
| true, TypeSystemHolder.class.getClassLoader()) |
| .getConstructor(new Class[] { Class.class }) |
| .newInstance(new java.lang.Object[] { TypeSystemHolder.class }); |
| } |
| catch (ClassNotFoundException e) |
| { |
| throw new RuntimeException("Cannot load org.apache.xmlbeans.impl.SchemaTypeSystemImpl: make sure xbean.jar is on the classpath.", e); |
| } |
| catch (Exception e) |
| { |
| throw new RuntimeException("Could not instantiate SchemaTypeSystemImpl (" + e.toString() + "): is the version of xbean.jar correct?", e); |
| } |
| } |
| } |