//$Id: ReflectHelper.java 10109 2006-07-12 15:39:59Z [email protected] $
package org.hibernate.util;
import java.lang.reflect.Constructor;
import java.lang.reflect.Member;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
import org.hibernate.AssertionFailure;
import org.hibernate.MappingException;
import org.hibernate.PropertyNotFoundException;
import org.hibernate.property.BasicPropertyAccessor;
import org.hibernate.property.DirectPropertyAccessor;
import org.hibernate.property.Getter;
import org.hibernate.property.PropertyAccessor;
import org.hibernate.type.PrimitiveType;
import org.hibernate.type.Type;
public final class ReflectHelper {
//TODO: this dependency is kinda Bad
private static final PropertyAccessor BASIC_PROPERTY_ACCESSOR = new BasicPropertyAccessor();
private static final PropertyAccessor DIRECT_PROPERTY_ACCESSOR = new DirectPropertyAccessor();
private static final Class[] NO_CLASSES = new Class[0];
private static final Class[] OBJECT = new Class[] { Object.class };
private static final Method OBJECT_EQUALS;
private static final Class[] NO_PARAM = new Class[] { };
private static final Method OBJECT_HASHCODE;
static {
Method eq;
Method hash;
try {
eq = Object.class.getMethod("equals", OBJECT);
hash = Object.class.getMethod("hashCode", NO_PARAM);
}
catch (Exception e) {
throw new AssertionFailure("Could not find Object.equals() or Object.hashCode()", e);
}
OBJECT_EQUALS = eq;
OBJECT_HASHCODE = hash;
}
public static boolean overridesEquals(Class clazz) {
Method equals;
try {
equals = clazz.getMethod("equals", OBJECT);
}
catch (NoSuchMethodException nsme) {
return false; //its an interface so we can't really tell anything...
}
return !OBJECT_EQUALS.equals(equals);
}
public static boolean overridesHashCode(Class clazz) {
Method hashCode;
try {
hashCode = clazz.getMethod("hashCode", NO_PARAM);
}
catch (NoSuchMethodException nsme) {
return false; //its an interface so we can't really tell anything...
}
return !OBJECT_HASHCODE.equals(hashCode);
}
public static Class reflectedPropertyClass(String className, String name) throws MappingException {
try {
Class clazz = ReflectHelper.classForName(className);
return getter(clazz, name).getReturnType();
}
catch (ClassNotFoundException cnfe) {
throw new MappingException("class " + className + " not found while looking for property: " + name, cnfe);
}
}
private static Getter getter(Class clazz, String name) throws MappingException {
try {
return BASIC_PROPERTY_ACCESSOR.getGetter(clazz, name);
}
catch (PropertyNotFoundException pnfe) {
return DIRECT_PROPERTY_ACCESSOR.getGetter(clazz, name);
}
}
public static Getter getGetter(Class theClass, String name) throws MappingException {
return BASIC_PROPERTY_ACCESSOR.getGetter(theClass, name);
}
public static Class classForName(String name) throws ClassNotFoundException {
try {
ClassLoader contextClassLoader = Thread.currentThread().getContextClassLoader();
if ( contextClassLoader != null ) {
return contextClassLoader.loadClass(name);
}
}
catch ( Throwable t ) {
}
return Class.forName( name );
}
public static Class classForName(String name, Class caller) throws ClassNotFoundException {
try {
ClassLoader contextClassLoader = Thread.currentThread().getContextClassLoader();
if ( contextClassLoader != null ) {
return contextClassLoader.loadClass( name );
}
}
catch ( Throwable e ) {
}
return Class.forName( name, true, caller.getClassLoader() );
}
public static boolean isPublic(Class clazz, Member member) {
return Modifier.isPublic( member.getModifiers() ) && Modifier.isPublic( clazz.getModifiers() );
}
public static Object getConstantValue(String name) {
Class clazz;
try {
clazz = classForName( StringHelper.qualifier( name ) );
}
catch ( Throwable t ) {
return null;
}
try {
return clazz.getField( StringHelper.unqualify( name ) ).get(null);
}
catch ( Throwable t ) {
return null;
}
}
public static Constructor getDefaultConstructor(Class clazz) throws PropertyNotFoundException {
if ( isAbstractClass(clazz) ) return null;
try {
Constructor constructor = clazz.getDeclaredConstructor(NO_CLASSES);
if ( !isPublic(clazz, constructor) ) {
constructor.setAccessible(true);
}
return constructor;
}
catch (NoSuchMethodException nme) {
throw new PropertyNotFoundException(
"Object class " + clazz.getName() +
" must declare a default (no-argument) constructor"
);
}
}
public static boolean isAbstractClass(Class clazz) {
int modifier = clazz.getModifiers();
return Modifier.isAbstract(modifier) || Modifier.isInterface(modifier);
}
public static boolean isFinalClass(Class clazz) {
return Modifier.isFinal( clazz.getModifiers() );
}
public static Constructor getConstructor(Class clazz, Type[] types) throws PropertyNotFoundException {
final Constructor[] candidates = clazz.getConstructors();
for ( int i=0; i<candidates.length; i++ ) {
final Constructor constructor = candidates[i];
final Class[] params = constructor.getParameterTypes();
if ( params.length==types.length ) {
boolean found = true;
for ( int j=0; j<params.length; j++ ) {
final boolean ok = params[j].isAssignableFrom( types[j].getReturnedClass() ) || (
types[j] instanceof PrimitiveType &&
params[j] == ( (PrimitiveType) types[j] ).getPrimitiveClass()
);
if (!ok) {
found = false;
break;
}
}
if (found) {
if ( !isPublic(clazz, constructor) ) constructor.setAccessible(true);
return constructor;
}
}
}
throw new PropertyNotFoundException( "no appropriate constructor in class: " + clazz.getName() );
}
public static Method getMethod(Class clazz, Method method) {
try {
return clazz.getMethod( method.getName(), method.getParameterTypes() );
}
catch (Exception e) {
return null;
}
}
private ReflectHelper() {}
}
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