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OPENJPA-1686: Support when a parameterized type has parameterized type arguments 

git-svn-id: https://svn.apache.org/repos/asf/openjpa/trunk@953717 13f79535-47bb-0310-9956-ffa450edef68
This commit is contained in:
Pinaki Poddar 2010-06-11 15:14:24 +00:00
parent 6b38f0cb8e
commit 59c7001e09
1 changed files with 63 additions and 50 deletions
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113
openjpa-lib/src/main/java/org/apache/openjpa/lib/util/JavaVersions.java
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@ -23,9 +23,11 @@ import java.lang.reflect.Method;
import java.security.AccessController;
/**
* Utilities for dealing with different Java spec versions.
* Utilities for dealing with different Java specification versions.
*
* @author Abe White
* @author Pinaki Poddar
*
* @nojavadoc
*/
public class JavaVersions {
@ -35,15 +37,17 @@ public class JavaVersions {
*/
public static final int VERSION;
private static final Class[] EMPTY_CLASSES = new Class[0];
private static final Class<?>[] EMPTY_CLASSES = new Class[0];
private static Class PARAM_TYPE = null;
private static Class ENUM_TYPE = null;
private static Class ANNO_TYPE = null;
private static Class<?> PARAM_TYPE = null;
private static Class<?> ENUM_TYPE = null;
private static Class<?> ANNO_TYPE = null;
private static Method GET_STACK = null;
private static Method SET_STACK = null;
private static Method GET_CAUSE = null;
private static Method INIT_CAUSE = null;
private static Object[] NO_ARGS = null;
private static Class<?>[] NO_CLASS_ARGS = null;
static {
String specVersion = AccessController.doPrivileged(
@ -63,8 +67,7 @@ public class JavaVersions {
if (VERSION >= 5) {
try {
PARAM_TYPE = Class.forName
("java.lang.reflect.ParameterizedType");
PARAM_TYPE = Class.forName("java.lang.reflect.ParameterizedType");
ENUM_TYPE = Class.forName("java.lang.Enum");
ANNO_TYPE = Class.forName("java.lang.annotation.Annotation");
} catch (Throwable t) {
@ -73,15 +76,11 @@ public class JavaVersions {
if (VERSION >= 4) {
try {
Class stack = Class.forName("[Ljava.lang.StackTraceElement;");
GET_STACK = Throwable.class.getMethod("getStackTrace",
(Class[]) null);
SET_STACK = Throwable.class.getMethod("setStackTrace",
new Class[]{ stack });
GET_CAUSE = Throwable.class.getMethod("getCause",
(Class[]) null);
INIT_CAUSE = Throwable.class.getMethod("initCause",
new Class[]{ Throwable.class });
Class<?> stack = Class.forName("[Ljava.lang.StackTraceElement;");
GET_STACK = Throwable.class.getMethod("getStackTrace", NO_CLASS_ARGS);
SET_STACK = Throwable.class.getMethod("setStackTrace", new Class[]{ stack });
GET_CAUSE = Throwable.class.getMethod("getCause", NO_CLASS_ARGS);
INIT_CAUSE = Throwable.class.getMethod("initCause", new Class[]{ Throwable.class });
} catch (Throwable t) {
}
}
@ -94,7 +93,7 @@ public class JavaVersions {
* @return the JDK-version-specific version of the class
* @see #getVersionSpecificClass(String)
*/
public static Class getVersionSpecificClass(Class base) {
public static Class<?> getVersionSpecificClass(Class<?> base) {
try {
return getVersionSpecificClass(base.getName());
} catch (ClassNotFoundException e) {
@ -125,14 +124,13 @@ public class JavaVersions {
* @param base the base name of the class to load
* @return the subclass appropriate for the current Java version
*/
public static Class getVersionSpecificClass(String base)
public static Class<?> getVersionSpecificClass(String base)
throws ClassNotFoundException {
for (int i = VERSION; i >= 1; i--) {
try {
return Class.forName(base + i);
} catch (Throwable e) {
// throwables might occur with bytecode that we
// cannot understand
// throwables might occur with bytecode that we cannot understand
}
}
return Class.forName(base);
@ -141,29 +139,28 @@ public class JavaVersions {
/**
* Return true if the given type is an annotation.
*/
public static boolean isAnnotation(Class cls) {
public static boolean isAnnotation(Class<?> cls) {
return ANNO_TYPE != null && ANNO_TYPE.isAssignableFrom(cls);
}
/**
* Return true if the given type is an enumeration.
*/
public static boolean isEnumeration(Class cls) {
public static boolean isEnumeration(Class<?> cls) {
return ENUM_TYPE != null && ENUM_TYPE.isAssignableFrom(cls);
}
/**
* Collects the parameterized type declarations for a given field.
*/
public static Class[] getParameterizedTypes(Field f) {
public static Class<?>[] getParameterizedTypes(Field f) {
if (f == null)
return null;
if (VERSION < 5)
return EMPTY_CLASSES;
try {
Object type = Field.class.getMethod("getGenericType",
(Class[]) null).invoke(f, (Object[]) null);
Object type = invokeGetter(f, "getGenericType");
return collectParameterizedTypes(type, f.getType());
} catch (Exception e) {
return EMPTY_CLASSES;
@ -173,15 +170,14 @@ public class JavaVersions {
/**
* Collects the parameterized return type declarations for a given method.
*/
public static Class[] getParameterizedTypes(Method meth) {
public static Class<?>[] getParameterizedTypes(Method meth) {
if (meth == null)
return null;
if (VERSION < 5)
return EMPTY_CLASSES;
try {
Object type = Method.class.getMethod("getGenericReturnType",
(Class[]) null).invoke(meth, (Object[]) null);
Object type = invokeGetter(meth, "getGenericReturnType");
return collectParameterizedTypes(type, meth.getReturnType());
} catch (Exception e) {
return EMPTY_CLASSES;
@ -191,28 +187,46 @@ public class JavaVersions {
/**
* Return all parameterized classes for the given type.
*/
private static Class[] collectParameterizedTypes(Object type, Class<?> cls)
throws Exception {
if (PARAM_TYPE == null || !PARAM_TYPE.isInstance(type)) {
if (cls.getSuperclass() != Object.class) {
return collectParameterizedTypes(cls.getGenericSuperclass(), cls.getSuperclass());
}
return EMPTY_CLASSES;
}
Object[] args = (Object[]) PARAM_TYPE.getMethod
("getActualTypeArguments", (Class[]) null).invoke(type,
(Object[]) null);
if (args.length == 0)
return EMPTY_CLASSES;
Class[] clss = new Class[args.length];
private static Class<?>[] collectParameterizedTypes(Object type, Class<?> cls) throws Exception {
if (isParameterizedType(type)) {
Object[] args = (Object[]) invokeGetter(type, "getActualTypeArguments");
Class<?>[] clss = new Class[args.length];
for (int i = 0; i < args.length; i++) {
if (!(args[i] instanceof Class))
Class<?> c = extractClass(args[i]);
if (c == null) {
return EMPTY_CLASSES;
clss[i] = (Class) args[i];
}
clss[i] = c;
}
return clss;
} else if (cls.getSuperclass() != Object.class) {
return collectParameterizedTypes(cls.getGenericSuperclass(), cls.getSuperclass());
} else {
return EMPTY_CLASSES;
}
}
/**
* Extracts the class from the given argument, if possible. Null otherwise.
*/
static Class<?> extractClass(Object o) throws Exception {
if (o == null)
return null;
if (o instanceof Class)
return (Class<?>)o;
if (isParameterizedType(o)) {
return extractClass(invokeGetter(o, "getRawType"));
}
return null;
}
static Object invokeGetter(Object target, String method) throws Exception {
return target.getClass().getMethod(method, NO_CLASS_ARGS).invoke(target, NO_ARGS);
}
static boolean isParameterizedType(Object cls) {
return PARAM_TYPE != null && PARAM_TYPE.isInstance(cls);
}
/**
@ -220,12 +234,11 @@ public class JavaVersions {
* false if it cannot be done, possibly due to an unsupported Java version.
*/
public static boolean transferStackTrace(Throwable from, Throwable to) {
if (GET_STACK == null || SET_STACK == null || from == null
|| to == null)
if (GET_STACK == null || SET_STACK == null || from == null || to == null)
return false;
try {
Object stack = GET_STACK.invoke(from, (Object[]) null);
Object stack = GET_STACK.invoke(from, NO_ARGS);
SET_STACK.invoke(to, new Object[]{ stack });
return true;
} catch (Throwable t) {
@ -241,7 +254,7 @@ public class JavaVersions {
return null;
try {
return (Throwable) GET_CAUSE.invoke(ex, (Object[]) null);
return (Throwable) GET_CAUSE.invoke(ex, NO_ARGS);
} catch (Throwable t) {
return null;
}