| package freemarker.ext.jython; |
| |
| import org.python.core.PySystemState; |
| |
| import freemarker.template.utility.StringUtil; |
| |
| /** |
| * Holds the {@link JythonVersionAdapter} so that it's only initialized when this class is accessed. |
| * This utilizes that the JVM is required to initialize the fields of a class not earlier than the class is |
| * first accessed. Furthermore, it utilizes that the JVM guarantees that the objects created as part of the class |
| * initialization will be visible with their after-initialization state for the threads that access it. |
| */ |
| class JythonVersionAdapterHolder { |
| |
| final static JythonVersionAdapter INSTANCE; |
| static { |
| // Note: Only the textual version number is available in Jython 2.0. |
| int version; |
| try { |
| // Although PySystemState.version is present in all versions, |
| // its type changes, so we must use reflection to get it. |
| version = StringUtil.versionStringToInt( |
| PySystemState.class.getField("version").get(null).toString()); |
| } catch (Exception e) { |
| throw new RuntimeException("Failed to get Jython version: " + e); |
| } |
| ClassLoader cl = JythonVersionAdapter.class.getClassLoader(); |
| try { |
| if (version >= 2005000) { |
| INSTANCE = (JythonVersionAdapter) cl.loadClass( |
| "freemarker.ext.jython._Jython25VersionAdapter") |
| .newInstance(); |
| } else if (version >= 2002000) { |
| INSTANCE = (JythonVersionAdapter) cl.loadClass( |
| "freemarker.ext.jython._Jython22VersionAdapter") |
| .newInstance(); |
| } else { |
| INSTANCE = (JythonVersionAdapter) cl.loadClass( |
| "freemarker.ext.jython._Jython20And21VersionAdapter") |
| .newInstance(); |
| } |
| } catch (ClassNotFoundException e) { |
| throw adapterCreationException(e); |
| } catch (IllegalAccessException e) { |
| throw adapterCreationException(e); |
| } catch (InstantiationException e) { |
| throw adapterCreationException(e); |
| } |
| } |
| |
| private static RuntimeException adapterCreationException(Exception e) { |
| return new RuntimeException( |
| "Unexpected exception when creating JythonVersionAdapter: " |
| + e); // No cause exception argument available on Java 1.2.; fix this with Java 5 |
| } |
| |
| } |