/*
This file is part of Cyclos (www.cyclos.org).
A project of the Social Trade Organisation (www.socialtrade.org).
Cyclos is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
Cyclos is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with Cyclos; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
package nl.strohalm.cyclos.utils;
import java.lang.annotation.Annotation;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Calendar;
import java.util.Collection;
import java.util.GregorianCalendar;
import java.util.LinkedHashMap;
import java.util.LinkedHashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.SortedMap;
import java.util.SortedSet;
import java.util.TreeMap;
import java.util.TreeSet;
import nl.strohalm.cyclos.utils.binding.BindingException;
import org.apache.commons.lang.ClassUtils;
/**
* Helper class for getting data about classes
* @author luis
*/
public final class ClassHelper {
/**
* Returns all implemented types for a given class - itself if a class and interfaces
*/
public static List<Class<?>> allImplementedTypes(Class<?> clazz) {
final Class<?>[] interfaces = clazz.getInterfaces();
final List<Class<?>> classes = new ArrayList<Class<?>>(interfaces.length + 1);
while (clazz != null && !clazz.equals(Object.class)) {
classes.add(clazz);
clazz = clazz.getSuperclass();
}
classes.addAll(Arrays.asList(interfaces));
return classes;
}
/**
* Casts a class to a required type
*/
@SuppressWarnings("unchecked")
public static <T> Class<T> cast(final Class<?> clazz) {
return (Class<T>) clazz;
}
/**
* If the class is concrete, return it. Else, try to find a well known subclass
* @param <T> The specified class type
* @param <C> The resulting class type
* @param clazz The specified class
* @return The class if it is concrete, or a well-known subclass.
* @throws IllegalArgumentException The specified class is abstract (or interface) and not a well-known one
*/
@SuppressWarnings({ "unchecked", "rawtypes" })
public static <T, C extends T> Class<C> concreteClass(final Class<T> clazz) {
if (clazz == null) {
throw new NullPointerException("null.clazz");
}
Class<C> ret = null;
final int modifiers = clazz.getModifiers();
if (Modifier.isAbstract(modifiers) || Modifier.isInterface(modifiers) || Collection.class.isAssignableFrom(clazz)) {
if (Calendar.class.isAssignableFrom(clazz)) {
ret = (Class) GregorianCalendar.class;
} else if (SortedSet.class.isAssignableFrom(clazz)) {
ret = (Class) TreeSet.class;
} else if (Set.class.isAssignableFrom(clazz)) {
ret = (Class) LinkedHashSet.class;
} else if (Collection.class.isAssignableFrom(clazz)) {
ret = (Class) ArrayList.class;
} else if (SortedMap.class.isAssignableFrom(clazz)) {
ret = (Class) TreeMap.class;
} else if (Map.class.isAssignableFrom(clazz)) {
ret = (Class) LinkedHashMap.class;
} else {
throw new IllegalArgumentException("Unknown concrete class for " + clazz.getName());
}
} else {
ret = (Class) clazz;
}
return ret;
}
/**
* Find a method annotation on the declaring class or in any of it's implemented interfaces
*/
public static <A extends Annotation> A findAnnotation(final Class<?> clazz, final Class<A> type) {
final List<Class<?>> classes = allImplementedTypes(clazz);
for (final Class<?> c : classes) {
try {
final A annotation = c.getAnnotation(type);
if (annotation != null) {
return annotation;
}
} catch (final Exception e) {
// Try next one
}
}
return null;
}
/**
* Find a method annotation on the method in any of it's implemented interfaces
*/
public static <A extends Annotation> A findAnnotation(final Method method, final Class<A> type) {
return findAnnotation(method, type, false);
}
/**
* Find a method annotation on the method or declaring class or in any of it's implemented interfaces
*/
public static <A extends Annotation> A findAnnotation(final Method method, final Class<A> type, final boolean searchInDeclaringClass) {
final Class<?> declaringClass = method.getDeclaringClass();
final List<Class<?>> classes = allImplementedTypes(declaringClass);
for (final Class<?> c : classes) {
try {
final Method m = c.getMethod(method.getName(), method.getParameterTypes());
final A annotation = m.getAnnotation(type);
if (annotation != null) {
return annotation;
}
} catch (final Exception e) {
// Try next one
}
}
// at this point the annotation was not found
if (searchInDeclaringClass) {
return findAnnotation(method.getDeclaringClass(), type);
} else {
return null;
}
}
/**
* Returns only the unqualified class name
* @param clazz The class
* @return The unqualified name
*/
public static String getClassName(final Class<?> clazz) {
final String name = clazz.getName();
final int pos = name.lastIndexOf('.');
if (pos < 0) {
return name;
} else {
return name.substring(pos + 1);
}
}
/**
* Create an instance of the class. If the class is a well known interface or abstract class (like Collection, List or Calendar), a concrete
* @param <T> The instance type
* @param clazz The class
* @return The instance
*/
@SuppressWarnings({ "unchecked", "rawtypes" })
public static <T> T instantiate(final Class<T> clazz) {
try {
final Object object = concreteClass((Class) clazz).newInstance();
return (T) object;
} catch (final Exception e) {
throw new BindingException("Could not instantiate bean of class " + clazz.getName(), e);
}
}
/**
* Returns if the given object is an instance of the specified class, handling primitives as objects
*/
public static boolean isInstance(Class<?> clazz, final Object object) {
if (clazz.isPrimitive()) {
clazz = ClassUtils.primitiveToWrapper(clazz);
}
return clazz.isInstance(object);
}
}