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package com.sun.jersey.server.impl.application;
import com.sun.jersey.core.reflection.ReflectionHelper;
import com.sun.jersey.core.spi.component.ProviderServices;
import com.sun.jersey.spi.container.ExceptionMapperContext;
import java.lang.reflect.ParameterizedType;
import java.lang.reflect.Type;
import java.lang.reflect.TypeVariable;
import java.util.HashSet;
import java.util.Set;
import javax.ws.rs.ext.ExceptionMapper;
/**
*
* @author Paul.Sandoz@Sun.Com
*/
public class ExceptionMapperFactory implements ExceptionMapperContext {
private static class ExceptionMapperType {
ExceptionMapper em;
Class<? extends Throwable> c;
public ExceptionMapperType(ExceptionMapper em, Class<? extends Throwable> c) {
this.em = em;
this.c = c;
}
}
private Set<ExceptionMapperType> emts = new HashSet<ExceptionMapperType>();
public ExceptionMapperFactory() {
}
public void init(ProviderServices providerServices) {
for (ExceptionMapper em : providerServices.getProviders(ExceptionMapper.class)) {
Class<? extends Throwable> c = getExceptionType(em.getClass());
if (c != null) {
emts.add(new ExceptionMapperType(em, c));
}
}
}
// ExceptionMapperContext
public ExceptionMapper find(Class<? extends Throwable> c) {
int distance = Integer.MAX_VALUE;
ExceptionMapper selectedEm = null;
for (ExceptionMapperType emt : emts) {
int d = distance(c, emt.c);
if (d < distance) {
distance = d;
selectedEm = emt.em;
if (distance == 0) break;
}
}
return selectedEm;
}
private int distance(Class<?> c, Class<?> emtc) {
int distance = 0;
if (!emtc.isAssignableFrom(c))
return Integer.MAX_VALUE;
while (c != emtc) {
c = c.getSuperclass();
distance++;
}
return distance;
}
@SuppressWarnings("unchecked")
private Class<? extends Throwable> getExceptionType(Class<? extends ExceptionMapper> c) {
Class<?> t = getType(c);
if (Throwable.class.isAssignableFrom(t))
return (Class<? extends Throwable>)t;
// TODO log warning
return null;
}
private Class getType(Class<? extends ExceptionMapper> c) {
Class _c = c;
while (_c != Object.class) {
Type[] ts = _c.getGenericInterfaces();
for (Type t : ts) {
if (t instanceof ParameterizedType) {
ParameterizedType pt = (ParameterizedType)t;
if (pt.getRawType() == ExceptionMapper.class) {
return getResolvedType(pt.getActualTypeArguments()[0], c, _c);
}
}
}
_c = _c.getSuperclass();
}
// This statement will never be reached
return null;
}
private Class getResolvedType(Type t, Class c, Class dc) {
if (t instanceof Class)
return (Class)t;
else if (t instanceof TypeVariable) {
ReflectionHelper.ClassTypePair ct = ReflectionHelper.
resolveTypeVariable(c, dc, (TypeVariable)t);
if (ct != null)
return ct.c;
else
return null;
} else if (t instanceof ParameterizedType) {
ParameterizedType pt = (ParameterizedType)t;
return (Class)pt.getRawType();
} else {
// TODO log
return null;
}
}
}