diff options
Diffstat (limited to 'sample/evolve/VersionManager.java')
| -rw-r--r-- | sample/evolve/VersionManager.java | 116 |
1 files changed, 58 insertions, 58 deletions
diff --git a/sample/evolve/VersionManager.java b/sample/evolve/VersionManager.java index d95268b8..184397fd 100644 --- a/sample/evolve/VersionManager.java +++ b/sample/evolve/VersionManager.java @@ -2,89 +2,89 @@ package sample.evolve; import java.util.Hashtable;
import java.lang.reflect.*;
-import javassist.CtClass;
/**
* Runtime system for class evolution
*/
public class VersionManager {
private static Hashtable versionNo = new Hashtable();
+
public final static String latestVersionField = "_version";
/**
* For updating the definition of class my.X, say:
- *
+ *
* VersionManager.update("my.X");
*/
public static void update(String qualifiedClassname)
- throws CannotUpdateException
- {
- try {
- Class c = getUpdatedClass(qualifiedClassname);
- Field f = c.getField(latestVersionField);
- f.set(null, c);
- }
- catch (ClassNotFoundException e) {
- throw new CannotUpdateException("cannot update class: "
- + qualifiedClassname);
- }
- catch (Exception e) {
- throw new CannotUpdateException(e);
- }
+ throws CannotUpdateException {
+ try {
+ Class c = getUpdatedClass(qualifiedClassname);
+ Field f = c.getField(latestVersionField);
+ f.set(null, c);
+ }
+ catch (ClassNotFoundException e) {
+ throw new CannotUpdateException("cannot update class: "
+ + qualifiedClassname);
+ }
+ catch (Exception e) {
+ throw new CannotUpdateException(e);
+ }
}
private static Class getUpdatedClass(String qualifiedClassname)
- throws ClassNotFoundException
- {
- int version;
- Object found = versionNo.get(qualifiedClassname);
- if (found == null)
- version = 0;
- else
- version = ((Integer)found).intValue() + 1;
+ throws ClassNotFoundException {
+ int version;
+ Object found = versionNo.get(qualifiedClassname);
+ if (found == null)
+ version = 0;
+ else
+ version = ((Integer)found).intValue() + 1;
- Class c = Class.forName(qualifiedClassname + '$' + version);
- versionNo.put(qualifiedClassname, new Integer(version));
- return c;
+ Class c = Class.forName(qualifiedClassname + '$' + version);
+ versionNo.put(qualifiedClassname, new Integer(version));
+ return c;
}
- /* initiaVersion() is used to initialize the _version field of
- * the updatable classes.
+ /*
+ * initiaVersion() is used to initialize the _version field of the updatable
+ * classes.
*/
public static Class initialVersion(String[] params) {
- try {
- return getUpdatedClass(params[0]);
- }
- catch (ClassNotFoundException e) {
- throw new RuntimeException("cannot initialize " + params[0]);
- }
+ try {
+ return getUpdatedClass(params[0]);
+ }
+ catch (ClassNotFoundException e) {
+ throw new RuntimeException("cannot initialize " + params[0]);
+ }
}
- /** make() performs the object creation of the updatable classes.
- * The expression "new <updatable class>" is replaced with a call
- * to this method.
+ /**
+ * make() performs the object creation of the updatable classes. The
+ * expression "new <updatable class>" is replaced with a call to this
+ * method.
*/
public static Object make(Class clazz, Object[] args) {
- Constructor[] constructors = clazz.getConstructors();
- int n = constructors.length;
- for (int i = 0; i < n; ++i) {
- try {
- return constructors[i].newInstance(args);
- }
- catch (IllegalArgumentException e) {
- // try again
- }
- catch (InstantiationException e) {
- throw new CannotCreateException(e);
- }
- catch (IllegalAccessException e) {
- throw new CannotCreateException(e);
- }
- catch (InvocationTargetException e) {
- throw new CannotCreateException(e);
- }
- }
+ Constructor[] constructors = clazz.getConstructors();
+ int n = constructors.length;
+ for (int i = 0; i < n; ++i) {
+ try {
+ return constructors[i].newInstance(args);
+ }
+ catch (IllegalArgumentException e) {
+ // try again
+ }
+ catch (InstantiationException e) {
+ throw new CannotCreateException(e);
+ }
+ catch (IllegalAccessException e) {
+ throw new CannotCreateException(e);
+ }
+ catch (InvocationTargetException e) {
+ throw new CannotCreateException(e);
+ }
+ }
- throw new CannotCreateException("no constructor matches");
+ throw new CannotCreateException("no constructor matches");
}
}
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